Classroom Instrument Maintenance and Repairs
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This page is intended to give the classroom teacher a helping hand in caring for, and repairing those classroom instruments usually associated with the ‘Orff Instrumentarium’. This includes classroom xylophones, metallophones, glockenspiels, as well as hand drums, tambours, tambourines, bongos, and congas. Many repairs to these instruments are very simple, the main difficulty being finding the materials required.
This guide is not intended for the repairs of concert instruments, although I have recently added some info on issues with Premier vibraphones.
It came from an article written a while back. I've just pasted it on a page here. Doesn't look pretty at the moment but I'll work on that.
Any suggestions re what to include will be gratefully considered.
The repairs outlined range in difficulty. Most can be carried out by those with basic ‘handy-person’ skills, while others may be more suitable to a joint venture between Music teacher and Woodworker, or even between Music, Woodwork, and Science teachers. Most ‘genuine’ spare parts, i.e. those supplied by the manufacturer of the instrument, are often very expensive, or simply not available. As well as this it should not be assumed that an original part is always the best replacement. It is if your concern is the instruments appearance, but some alternatives suggested here are often better in terms of durability and price, and use locally manufactured materials. The section on making bars in particular might be of interest to teachers of Woodwork, Science, and Music, in demonstrating some aspects off sound in a practical application. The repairs described here are mainly on instruments I have come across in Victoria. Schools in Victoria tend to have mostly Suzuki, Studio 49, Sonor, and, more recently, Optimum Percussion instruments. There are the odd “New Era” and “Bauer’ instruments, as well as my own Musaics instruments. Most classroom instruments are similar in construction though, and similar principles apply.
Web site: www.musaics.com.au
Taking care of instruments. The first section.
REPAIRING YOUR INSTRUMENTS
PINS THAT HOLD NOTES IN PLACE
METALOPHONE DAMPER RUBBERS
REPAIRING TAMBOURS AND HAND DRUMS
LIST OF SUPPLIERS OF USEFUL MATERIALS AND PARTS
PREMIER VIBRAPHONE ELECTRICALS
CONCERT XYLOPHONE AND VIBRAPHONE BAR SUPPORT POSTS
TAKING CARE OF INSTRUMENTS
Taking a little care of your instruments will save on repairs further down the road. Some parts, eg rubber that perishes (especially in warmer climates), will always need to be replaced at some stage, but their life can be maximized by taking precautions against that which causes them to wear and deteriorate.
XYLOPHONES AND METALOPHONES.
Common problems are:
a): Bar placement pins breaking or bending.
Pins break because they are bent and straightened too many times, or when the bars are removed incorrectly. The pins on Suzuki instruments are soft and thin, and break easily. Other instruments, i.e. some Sonor, have plastic pins which bend easily. Teach students to remove bars gently, and in such a way as to not bend pins, and they could last forever. Best practice is to use 2 hands, one on each end of the bar, and lift both ends together, or remove them by lifting from the side of the instrument that has the pins that locate through the hole in the bar, not the opposite end. Studio 49 pins are harder to bend and seem to last longer, but are very difficult to replace on those models that use fiberglass boxes. The flexible pins on Sonor instruments are a good idea, as they bend back, but they won’t do it for ever.
b): Bar support rubbers perishing.
Rubber perishes, so the tubing supporting the bars will eventually need replacing. Its life can be greatly extended however, by taking some precautions. Firstly, don’t store your instruments where they will be subjected to heat and/or direct sunlight. If you have a room with west facing windows, you could melt the rubbers in one hot afternoon by placing them in the direct sun. Metallophone bars can get very hot, particularly the black Suzuki chromatic metallophone bars. Leaving them in the car on even a warm day can age the rubber, while a hot day could destroy them. Store instruments away from light if possible. A cupboard is ideal, but throwing a sheet over them if you leave them out over the weekend will also protect them as well as stopping dust settling in the instruments. The rubber on earlier Suzuki instruments is particularly prone to melting and perishing. Suzuki have rectified this in their newer instruments. Replacing them with a higher quality rubber when the time comes is easy. Avoid stacking things on, or other instruments on top of instruments in such a way that places excessive load on the rubbers. Only place an instrument on top of another if the upper instrument is supported on the ends of the box of the lower one. If the weight is bearing on the bars, the rubbers will be squashed. Do this too many times, or just once on a hot day, and they could remain flattened. Using some spare pieces of wood, or the chromatic F sharp and B flat bars placed on the ends of on instrument will give a little more height so the box will clear the bars. Often you can place similar instruments on top of each other, i.e. a Suzuki Alto Xylophone will happily sit on top of another Suzuki Alto, as long as the end feet sit on top of the end plates.
(c) Missing Bars
As with many ‘spare parts’, these days, they are so expensive that putting an instrument together from original spare parts would result in an instrument many times the original cost. Replacing several bars over a few years means that you may have paid for your instrument again. I once made a replacement bar for a teacher from a type of wood that, although worked perfectly well, was so different in colour from the original as to stick out more than any proverbial sore thumb. She liked it as a reminder to students of the consequences of loosing a bar. Replacement bars from the original manufacturer are sometimes available, but rarely kept in stock by the importers, and can be very expensive and take a long time to order.
d): Rubber Feet
Many people are not aware that their Suzuki Xylophones and Metalophones have rubber feet. These are attached with small screws. Unfortunately a rubber foot often parts company with the screw when the instrument is pushed along a surface which it tries to cling to, like table tops, wooden floors etc. After a while the screw is left behind to make nasty gouges in the surfaces the rubber was intended to protect. These rubber feet are not available from the importers. I suggest removing the screws and leave it at that. The bottom of the instrument, being wooden, should not be to hard on tabletops and floors. Most other good brands don’t have rubber feet, and seem to live happily without causing damage to the surfaces that support them. If you prefer to replace them, you could try rubber suppliers for something to replace them with. I would suggest that you replace them with a larger foot held in by two screws. I have used one that is about 40 mm long and 10 mm wide, with two screws through it, on some bass instruments, but there are bound to be other suitable feet around, depending on stocks at your local rubber supplies store.
Instruments like tambours, tambourines and hand drums that use a piece of vellum or plastic should of coarse be played correctly, and with the correct beater, which is usually ones hand! Don’t use drumsticks on these thin plastic or vellum skins, as they can be permanently dented. Unfortunately replacement skins with the metal hoop attached, or ‘heads’ as drummers would call them, seem to be available in plastic only these days. If you prefer the sound of vellum (goats skin) you could buy a piece of vellum and attach it to the metal hoop of your damaged plastic one. This procedure is covered later in this article. Also avoid over-tuning them (winding the tuners to tight). Plastic heads do not react to higher temperatures as much as vellum heads. It is always a good idea to keep them in a cool place to avoid them stretching with heat and sounding flat when the temperature returns to normal. If your instruments are tunable, i.e. they have tuners on the side, always de-tune them before taking them in a hot car, or storing in a warm or hot place. Instruments that are not adjustable, but have the skin permanently attached to the side, are less desirable for normal classroom use. They may cost less to buy but they cannot be tuned, and cost more to repair if a new skin is needed. I have rarely seen one of these that is more than a few months old, that has any tone left at all. These instruments have a hard life in the classroom, and you need to be able to retune them once they have had ‘a bit of a stretch’. The only way to retune these non-adjustable types is to remove the skin, soak in water, and reattach. This is described in detail in the repair section of this article. Instruments with tuners on them are easy to repair, as new replacement skins are available and very easy to replace.
Autoharps seem to becoming rare these days. The remaining ones seem to be stacked in store rooms and caked in dust. This does nothing for the tone of the strings, especially the wound strings in the lower register. Dust gets into the windings and does not allow the string to vibrate clearly, resulting in a dull tone. Keeping them in boxes or cupboards, or even storing them in an upright position would be better. Rust can compromise tone as well as making the instrument feel unattractive to play, so wipe them down occasionally.
Tuning autoharps requires a suitable ‘tuning hammer’, the tool required to turn the pegs around which the strings are wound. These pegs are screwed into the wood using a fine thread in the same manner in which piano strings are attached. Pegs are turned to either tighten or loosen the strings to adjust tuning. When replacing strings it is possible that they might be unscrewed a long way out of the instrument, with the result that insufficient threads remain engaged in the instrument to secure the peg in the proper position when the string is replaced. The peg must be screwed back so that enough threads engage to hold the fully tensioned string without the possibility of the peg being pulled out by the string and causing damage to the wood. Tuning is easy, but a long process, with an electronic tuner.
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REPAIRING YOUR OWN INSTRUMENTS
Many people, in approaching me for repairs to instruments, often mention that buying new ones is out of the question, so, ‘can we give these old things a new lease of life?’. There is no reason why an old (or often not so old) xylophone or metallophone will not last at least as long again, with the necessary and often simple and inexpensive repairs. Many wooden instruments tend to improve with age. Wooden xylophone bars treated properly (ie not hammered with the wrong mallets) also can improve as they continue to ‘season’ with age. I have seen some old Studio 49 series 2000 xylophones that sound better than any new one will for many years. In this section I describe some of the most common and simple repairs I am asked to carry out on Xylophones, Metallophones, Glockenspiels, Tambours, Tambourines, hand drums and Autoharps.
Xylophones and Metalophones.
Repairs on these instruments range from replacing pins and rubbers to making your own bars. Making bars itself can be as simple or complicated as you want it to be, depending on the extent to which you are prepared to learn about the science involved. In the section dealing with bars I have included a description of the goings on when a bar is struck. This section may seem as though it is aimed at the science rather than the music teacher, but then the science of musical instruments needs to be considered if you are going to make a bar that is tuned as well as the others on most of the better quality instruments. There are also many articles on the science of marimba and xylophone bars on the Internet, but we will start with the easier and more common repairs.
Bar Support Rubbers.
The most common problem with a Xylophones and Metallophone seems to be that the rubber supporting the bars perishes, or melts. This is very common with older Suzuki instruments (which I suspect were not designed with the Australian sun in mind), and less so with Studio 49 (depending on the model). Leave them in a hot room, especially with a bit of sun through the window directly on them and the rubber soon perishes. Often the rubber needs to support the added weight of other objects placed on top of the instrument, squashing the rubber even more (not a good idea). The result can sound terrible. In replacing the tubing you have two options:
1. If you have a Suzuki that uses the older very soft black rubber, then you may wish to use the new Suzuki cloth covered rubber. This can be purchased through myself or any music shop willing to help you. It is imported through Lamberti Brothers (in Australia). New rubber for Studio 49 and Optimum Percussion brands are available through Optimum Percussion in Sydney.
2. There are other much cheaper options. I have started using a clear silicon tubing sold by aquarium supply shops. This material has an internal diameter of about 4mm. It seems to come in 2 brands. One is called “air line hose” while the other is called “aquarium tubing”. The 1st is a little harder and perhaps more durable, but both types work well enough. The softer one may not last as long, but may work better for smaller higher pitched instruments. I’m not sure of the relative longevity of these 2 types of materials as I have only been using them for about 8 years, and so far have not been back to replace anything with this tubing. It’s cheap and easily available.
A rubber tubing known as “Surgical Tubing” is available through some rubber suppliers, but is getting harder and more expensive to get. This is an orange coloured rubber. It does not last as long as the clear aquarium tubing, and costs more. It is available in different sizes though, so could be good for those small glocks that require thinner tubing. Just match the size of the tubing on your instrument, and replace (read on).
3. Tubing with a thicker wall, such as ‘Gas Tubing’, is not appropriate as the tubing needs to absorb the impact of the beater hitting the bar, without responding by bouncing the bar up and off the instrument. Tubing with a thicker wall is much more ‘springy’ and will not absorb the energy imparted by a player hitting the bar. Harder tubing such as plastic may also cause too much bounce, and give rise to ‘buzzing’ noises as bars vibrate against the harder surface.
You could of coarse experiment with any type of material, e.g. felt, or other tubing at hand, as long as it is able to do the job described above. I do sell all the possibilities mentioned above, although don’t have much surgical stuff left. Replacing tubing is simply a matter of taking/peeling/scraping the old tubing off, winding the new tubing in between the posts, and securing it at either end. The very first xylophone I repaired was completed with surgical tubing secured at each end with staples from a desk stapler. I saw it three years later, still as good as the day I repaired it. This particular Xylophone was used at a tertiary level, and not subject to the demands of primary school music sessions, but it does show that as long as tubing is reasonably secure, it should stay there. I now use small (aprox 10 mm) tacks, together with a little contact adhesive. It is also possible to use drawing pins securing the tubing to the inside of the box. Any way of securing the tubing is OK as long as it does not cause buzzing noises if the metal securing item comes into contact with the bar.
So, to list required parts, you will need:
• Approximately 1 meter of tubing.
• Four tacks approximately 10 millimeters long,
• Contact adhesive, P.V.A. glue, or any other glue that will glue rubber to wood.
1. Small hammer.
2. Concave nail punch, to get the tacks in the small spaces between the pins and end of the instrument.
The aim is to simply lay the rubber on the instrument in the same way as the original, i.e. winding it between the pins, and securing it at either end. It is very important however to not stretch the rubber in any way. Simply lay the tubing in place. This sort of rubber does not last long under tension, and if stretched will tend to cause the bar to rebound more when struck by the beater, possibly bouncing it off the instrument. Make sure that the small pins used to secure the rubber are positioned in such a way as to not come into contact with the bars. This would cause buzzing noises.
If you own a Studio 49 instrument that uses the specially molded rubber that covers the pins and supports the bars, this is now available from Optimum Percussion in Sydney, who are the importers of Studio 49 and their own Optimum brand. The Optimum brand of molding works fine on Studio 49 instruments. You can however replace all this with the tubing described, but will need to glue small sections of tubing on the pins. This can be any type of tubing that fits both around the pin, and inside the hole in the bar. The genuine material is very easy to replace, as it needs no fixing or gluing, but the alternative, though more work, will be less expensive. Sonor instruments often use a material similar to the cloth covered rubber now used by Suzuki, though this will depend on model and age. Again, replace with whatever you have on hand as above.
Another instrument I have seen, though rarely, is an English make; ‘New Era’. Not available now for many years, these xylophones and metallophones have bars similar to the Studio 49 2000 series, ie the xylophone bars have a curved top surface , and the metallophone bars appear to be the same size as their Studio 49 counterpart. The pins used in these instruments are a flat nail, with protrusions that keep the rubber on. The rubbers are individually molded pieces that fit over the pins and under the edge of each bar. These rubbers are no longer available, as these instruments are no longer made.
Due to the nature of the placement and shape of these pins, it is not a good idea to simply wind some tubing between them. I would suggest using some 8 mm surgical tubing, and, using a hole punch, make small holes along the length of the tube so that it can be placed in a straight line along the top of the instrument, with the pins through the holes.
Next, use 6 mm out side diameter ‘gas tubing’, for the posts. This tubing has a much thicker wall than surgical tubing, and so is much stronger. Cut pieces long enough to push down over the pins and go up through the hole in bar. This length will depend on the type of instrument, as bars vary in thickness depending on whether they are bass or alto xylophones, or metallophones. The result will look neat as long as the gas tubing around the pins is pushed right down onto the horizontal tubing.
Glockenspiels are the smaller metal bar instruments that typically do not have any resonating chambers and are often just a frame supporting the bars. These instruments usually use smaller tubing, or rubber. The Studio 49 glockenspiel rubber can be replaced using a solid ‘sausage’ type rubber called ‘gum’, or soft small tubing, (which I am finding hard to source these days). This can be replaced by lifting the drawing pins holding the rubber down with a small screw driver or knife, and simply winding the new material in its place, and securing it with the same drawing pins. You will need to obtain 3-millimeter gum sausage for this. Remember to place the rubber without stretching it.
Suzuki glockenspiels use a special molded rubber. These are best replaced by the original, which, surprisingly, are reasonably priced and tend to last a long time. The most common problem is that they tend to work lose, and then get lost, rather than actually wearing out. Suzuki use staples and a glue to secure them, but the staples seem not to be able to stay in place. When replacing them, use good glue together with tacks or decent size staples and they should stay there. Suzuki parts are available from music shops that deal with Lamberti Brothers music importers.
Another common instrument is the chromatic glockenspiel made by ‘Canora’ or ‘Angel’. These often don’t have a brand name on them but use either white and black, or red and white keys for diatonic and chromatic bars respectively. They are built on a wooden frame, usually using felt to support the bars and a specially molded pin rubber with a nail going through them that keeps the bars in place. As far as I know this felt and the pins are not available from music suppliers. I have tended to use old instruments for spare pins. The felt is best replaced by furniture felt available at hardware stores. This material is used for the bottom of furniture legs. It comes in rolls of around 1 meter long and 25 or so mm wide, and has a sticky backing. Just cut a length of the required width, peel of the backing strip, and stick in place. These instruments are relatively inexpensive to purchase, and impossible to buy parts for. It is recommended therefore that unless you can affect the repairs yourself, or have access to someone who can, you may want to weigh up the cost of repairs that you pay for against the cost of a new instrument, and keep the old one for parts.
These instruments are constructed on a wooden frame that is not really ‘student proof’, and tends to break easily. The frames can be easily repaired by someone with some basic woodworking skills. It is suggested that if this is undertaken, they be reinforced by mounting on a sheet of plywood, or chipboard or some such material the size of the instrument, so that the frame is strengthened. Replacement pins are dealt with in the next section.
Another common instrument is the small glockenspiel in the yellow plastic carrying case. I have found that buying a full complement of pins for one of these is about twice the replacement cost of the entire instrument. Often the plastic, in which the pins locate, breaks. You can try replacing both the pin and the broken off portion of plastic with Araldite adhesive. If this does not hold it is best to purchase another instrument and save the old one for parts. These are not a good quality instrument, so I guarantee you won’t be sorry by replacing them with something better.
There are of course various other brands of instruments that are not mentioned here. Often it is not possible to obtain spare parts for many cheaper instruments. I tend to keep old un-repairable instruments to be used for parts to repair others. Even though I have not mentioned a particular instrument you wish to repair, it is likely that it is similar to the ones described above. This might be a chance at extending ones musical creativity to the ‘hardware’ side of your repertoire and devise your own repair.
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The pins, (or posts), are those upright objects holding the bars apart and in place. They are, except for ‘Sonor’ instruments, made up of some sort of nail inside a rubber sleeve. Sonor instruments use a flexible plastic pin.
If pins are bent, gently straighten them. Keep in mind that bending and straightening them will in time cause them to break. Suzuki pins are soft and can be straightened by hand. Studio 49 pins are harder, and may require the use of pliers. If pliers are used on any instrument, take the rubber sleeve of first, or you may find the metal nail poking through the rubber. Sonor pins are of coarse designed to be flexible and bend back themselves, but only as long as they are not bent to far, and not to many times.
Suzuki pins are a special rubber molding designed to keep the bars in place, with a metal nail through the center. The nail has small twisted spines on it, resembling a screw. If you need to remove one, this is best done by gripping the nail head with a pair of pliers, pulling, while at the same time twisting the nail anti-clockwise, as if to remove a screw with pliers. Suzuki instruments are made from chipboard, so, taking a little care to remove the old nail in this manner will ensure the hole does not increase in size to much, and so will accommodate the new nail without it being to lose in the wood.
In the event that the pin has broken off flush with the surface of the wood (as is usually the case), I suggest you hammer another one in right next to it. If there are 2 or more broken pin-remains in place however, you will need to remove these bits, as hammering more nails in place will split the soft chipboard. The best tool for this is small wire cutters. Just dig them in around the top of the nail, removing as little timber as possible, until you get a grip and then pull it out. If possible, twist anti clockwise at the same time. Suzuki instruments are made of chipboard, so the wood will be soft. If you have removed so much wood in digging out the old nail that you don’t have enough wood to secure the new one neatly, or, the hole is now too big, proceed as follows.
1) Remove nail
2) Drill a 6 millimeter hole about twenty five millimeters (1 inch) deep. Be careful to drill straight down.
3) Cut a piece of 6 millimeter dowel the same length as the hole is deep.
4) Apply a little PVA wood glue to the dowel and drive the dowel
into the hole with a hammer so that it is flush with the top of the instrument side panel. You now have a nice new piece of wood to secure a new pin.
5) It is best to pre-drill the hole for the new pin with a small drill before hammering in the new nail, as this will guide it into place.
If the dowel you are using is wider than 6mm, and 6 mm dowel is often more like 6.5 or 7 mm in diameter, then drill the hole that size. If the hole is not big enough the chipboard will easily split when driving in an oversize piece of dowel.
Replacing the post is easy if the original hole is to be used. If you are replacing a Suzuki type post, with a spiral nail, simply ‘screw’ the nail back in with pliers. If you are replacing a Suzuki type nail into a newly replaced piece of dowel, you will need to hammer it in, unless you pre-drill, as suggested above. When hammering in one of these nails, be careful as the heads are dome shaped and chrome plated. This makes them very ‘slippery’, and will bend very easily unless you are very skilled with a hammer.
Studio 49 instruments are made from a variety of materials, from five-ply wood to fiber glass foam, depending on their age and model. If you have a xylophone that is made from foam-fiberglass that has a broken pin, you may need to do a little surgery. These instruments have pins that are flathead nails embedded upside down in the material, (the head being held in the fiberglass) so you will not be able to pull out the remaining piece without doing damage to the xylophone box. You will need to drill around the pin so that it can be removed, and then replace with a similar nail, and fill the hole with epoxy resin, Araldite, or fiberglass filler, or wooden dowel as described above.
MAKING YOUR OWN PINS
You may wish to make a pin using a nail of suitable size, with a piece of rubber tubing around it. This may not look as good but works just as well, and is much cheaper. A nail with a head would be the best, as this will assist in keeping the rubber on. I have found that the bigger flatheads however may overlap the top of the edge of the rubber tube and touch the bar, giving rise to those buzzing noises. These bigger heads can be filed so as not to protrude over the edge of the rubber sleeve.
For Suzuki instruments, 30 mm by 2.5 mm “Trimedge Nails” (available at most hardware shops) work well and look very much like the original Suzuki nails, but any other nail of similar thickness and length will do. You will also need two types of rubber. The ‘head’ is made by slicing a 4 or 5 mm length of 8 mm thick sausage’ rubber. This rubber is solid (ie no hole down the center), so you will need to drive the nail through the center. Next push on a piece of rubber tubing with inside diameter, 2 or 3 mm, outside diameter about 4 mm, and long enough to match the other pins on the instrument. The result should look like a mushroom.
If you have a fiberglass Studio 49 instrument with a broken nail, this is somewhat more difficult to repair. The nail is in fact a flat head nail embedded in the material with the head at the bottom, so as to locate it in the fiberglass. To see if your instrument is a fiberglass model you will need to look inside or underneath the box of the instrument, as the outside has a wood veneer. The underneath and inside will look like a plastic type material. These instruments are also very light.
To replace this would mean breaking or drilling away the fiberglass till the head of the nail is visible, replacing it with a similar size nail which will need to have its point filed flat, and then replacing the fiber glass. The fiberglass can be replaced with car body repair fiberglass, available from most auto shops (eg. Repco, Autobarn etc.) and some hardware suppliers, or araldite, or a piece of wooden dowel. Sometimes sections of these instruments will break away if the pins are struck against something, or the bars thrust against the side of a cupboard in such a way as to force the pins to break the fiberglass. This sort of material can be easily glued back in place with araldite and a clamp, or, if the section is missing, clamp a piece of wood to the side so that you can fill in the missing bit with auto fiberglass repair resin. Breaking a nail on these instruments is fortunately a very rare occurrence, and its repair, though not difficult, does require some fiddling with mixing hardener with fiberglass etc.
On some of those un-branded instruments mentioned earlier, you may find they have small pins that are mushroom shaped. These are no longer available. All I can suggest is making them yourself. All you need to do is to match the two sizes of the mushroom with some rubber, get some nails that resemble the original in size, and put it all together. Number 4 gauge screws about 25 to 30 mm long also work well, and can be screwed in. Name brands of instruments tend to be in there for the long haul, have been around for years, and tend to be better supported with spares, though sometimes at considerable cost. Often the original nail, minus the rubber, is still in the instrument, so all you need to do is remove it (by using pliers and twisting as if to unscrew it), add the rubber, and replace it (with pliers, screwing it back in).
If you own a Sonor instrument with broken posts, you will find them very easy to replace, as long as you can extract the broken section of the pin that remains. Sonor posts are made from flexible plastic, and readily available from a music shop that deals with K.J. Music in Sydney, the importers of Sonor. Simply pull the old one out, using pliers, and push the new one in. If the pin has broken off flush with the wood so it can’t be gripped, I suggest drilling part of it out with a drill smaller in diameter than the pin and then pulling the rest of it out. This is very fiddly, but getting it out without damaging the hole will give you a neater job. It would be possible to replace with a home made pin, made up as described above, but this would require filling the hole with dowel, or something similar, drilling, and then installing the pin. This would look very different to the other posts, and would not flex in the same manner, but would work fine.
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METALOPHONE DAMPER RUBBERS
Some Metalophones, eg Suzuki and some Studio 49 have a damper bar fitted. This is the long bar that runs the length of the instrument just underneath one end of the bars. This bar is nearly always adjusted incorrectly, so as to damp out only some of the bars at best, and usually the rubbers have perished, especially on the Suzuki ones. I have never met anyone who actually uses them, but as metal bars have much longer sustain than wooden bars, playing one without using the damper is like playing the piano with your foot permanently on the right pedal. Often I just remove them, as they have never been used, and the teacher has determined they never will be, after discovering what they in fact are.
To replace the damper bar rubber, proceed as follows:
1) Unscrew both ends of the damper bar from the mounts. You will need a suitable Phillips-head screwdriver for this. The bar can now be removed.
2) Remove old rubber. If this is a Suzuki you might try using a long serrated bread knife. Using the serrations will help cut through the old rubber. Don’t worry about removing every last speck from the bar, as you only want to remove most of it to allow the new rubber to slide on over it. Leaving a little of the last few difficult to remove bits will help keep the new rubber in place.
3) Replace new rubber. If you have a Suzuki, I would suggest a piece of ‘gas tubing’ with inside diameter of 12 mm, and outside diameter of 17 mm. Cut the tubing to length, apply a little ‘Contact Adhesive’, or other suitable adhesive, and slide the new rubber on. This might feel difficult, but if you place one end on a table and grip the tubing just above where it is about to slide on to the bar, you will be able to push it on slowly.
4) Replace the bar by replacing the screws through the mounts into the ends of the bar.
5) The damper bar should be placed so that it sits up against the side of the instrument. The handle, that little curved piece of metal attached by a wing nut to a metal tube alongside the damper bar, is then adjusted to suite right or left hand, and the angle to facilitate ease of operation for sitting or standing positions. You will need to loosen the wing nut and re-tighten after adjustment.
BARS BARS BARS
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In Australia we have a situation where instruments come mainly from Germany, Japan, China, and Taiwan. All these places have their unique climates, as do we. A wooden Xylophone bar may start out tuned to concert pitch in its northern hemisphere climate, and end up going sharp in Australia as it dries out a little more in adjusting to our drier climate. Wooden bars will also change as they dry out more over time. Metal bars are not likely to change pitch, although I have noticed small variations according to brand. The result is Suzuki, Studio 49, Sonor, and whatever else, being not quite compatible in tuning. This will explain the slight discomfort you may feel in combining various brands. The solution is to retune them. In my experience bars mostly go sharp in Australia. If you have access to an electronic tuner, you could check your various instruments to see where they are in relation to concert pitch. If they are sharp, removing wood from the underneath center third of the bar (where wood has already been removed) will bring the pitch down. If the bar is flat (to low in pitch), you will need to remove wood from the ends of the bar, usually by drilling the underneath of the bar near the ends, in equal amounts, with a bottoming drill just smaller in diameter than the width of the bar. If the bar is low in pitch, I would suspect that it has been abused a bit, possibly played with drum sticks or the like, or may have a split or some fault. The normal tendency is for xylophone and marimba bars to slowly go sharp.
To remove wood from the center I advise using a coarse piece of sandpaper. It will take a little longer than other powered means, but will help you in not going to far, ie, in removing to much wood from the center, resulting in the pitch being to flat, and then having to drill in the ends to bring the pitch up again. I use a belt sander set in an upside down position for this, but, should you try it, extreme care should be taken both in not removing to much wood (you only need to remove a very small amount), and not removing part of your fingers (they don’t need tuning).
Do not attempt re-tuning using hammer and chisel. This method may be ok (for some) for making the larger bars on marimbas, but could easily split, or reduce your bar to having no tone at all, as it is not possible to remove an even thickness of two or three thousands of an inch off the area in question. I also advise using an electronic tuner. You may find that testing the bar with a tuner a few minutes after tuning it will give you a different result to when it was tuned. This is due to the fact you tend to create heat when applying sandpaper to wood, which tends to make it flat in pitch. The tuning may shift again as it cools (going sharp). These factors will vary from bar to bar, and brand to brand, as manufacturers do not all use the same wood. For this reason you might want to retune a bar several times over a week or so, depending on how particular you are, bearing in mind that you will always have variations as the air temperature.
Most electronic tuners these days will show ‘cents’ on their scale. A ‘cent’ in this case is one hundredth of a semitone, so there are one hundred cents in a semitone. It is generally accepted that the best the human ear can do is discriminate between two notes no less than five cents apart, and this would be the very best ‘ear’. Most of us would not be able to pick a larger difference, though I have noticed that when I spend a lot of time making bars, and I have made many bars, I am able to pick a difference of 5 cents. It would seem then that if you could tune all your bars on all your instruments to be within five cents of each other on any given day, you would for all intends and purposes have a perfectly tuned instrumentarium, that not even the best ear could fault. This is entirely possible but would take some careful work. Your ensemble playing though would sound wonderful! At least from a pitch point of view.
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Many of the newly made marimbas made in workshops in schools etc will tend to go out of tune in just several weeks, and often by a lot, if you do not use well seasoned timber. This is not a big problem. The reason is most probably because the wood is continuing to dry out, or ‘season’. Most of the Marimba bars made in school workshops that have been very popular of late seem to be made from what is known as ‘K.D. (kiln dried) hardwood’. This timber is used in the building industry. It is dried out only to a point that is adequate for building, and not really for marimba bar making.
The remedy is just to keep tuning them until they stabilize. This could take some months, or more likely, years, depending on how dry the wood was to start with, the type of hard wood it is, how thick the bars are, the time of year, etc. It is always a good idea to tune them sooner rather than later as having an out of tune instrument is counterproductive to developing good pitch discrimination in children, especially those that may have perfect pitch, who would find such an instrument very difficult to play.
Another solution would be to seal the bars with a polyurethane type clear finish. They will still dry out but much more slowly, as the moisture in the wood will have to pass through the finish first, and so the pitch will hopefully not change as radically. Ideally you would be able to make your bar, or bars, store them somewhere away from extreme temperature fluctuations for at least a year, then re-tune them, apply some finish, and away you go. Wood used in musical instruments seasons, and improves its tone and volume of sound as it dries out and is played. This is why in the music world, older high quality wooden instruments are often preferred to a newer one. It is always a good idea to varnish a bar as they can re-absorb moisture at times when there is moisture in the air, ie when it rains a lot, and then dry out again, when the sun comes out for a while etc. as well as protecting the wood against staining.
The only way to avoid the problem of bars going out of tune a lot is to use timber that has been air-drying for about two years or more. This will save a lot of time re-tuning many times as they dry out. Make the bars and seal them with a varnish and they should stay in tune, with minor adjustments at most needed some time later.
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Before describing how to make a bar, I will go through some of the ‘theory’, or physics involved in making sound from wood. Understanding this section is not a necessary requirement for making a bar, but will give you an insight into what is happening, why we do certain things, and why some bars just sound better, or louder than others even though they all appear to be fundamentally in tune. For those wanting to explore this a little more, there are numerous articles on this on the internet.
I would like to start by looking at vibrations in strings. We are all aware that a plucked string vibrates. A guitar string, which is secured at both ends appears to vibrate between two points as shown.
Those people who play a stringed instrument would be aware that you can play ‘harmonics’ on a string. If you have never done this, try the following: Take a guitar, and halfway up any one string, right above the 12th fret (usually there will be a dot on the side of the neck at this point) place your finger lightly on the string, without pushing it to the fret board. This means resting your finger on the string above the twelfth fret. Pluck the string and immediately take your finger away. The resulting tone will be an octave above the open string. The open string is called the ‘fundamental’, while the tone produced by lightly holding your finger and plucking is called a ‘partial’, or ‘harmonic’, meaning that it is a partial vibration of the string. This particular partial is called the ‘first harmonic’ by musicians, but often referred to as the ‘second harmonic’ by engineers, who tend to refer to the fundamental as the first harmonic. The diagram below shows this partial vibration. The dotted line shows the “null point” which does not move.
The reason the string now vibrates at this pitch is that by placing your finger over the twelfth fret, you damped out the ability of the string to vibrate at its fundamental frequency. In this way the lowest and loudest pitch it is now able to vibrate at is this first harmonic.
Now rest your finger over the seventh fret, play as you did before, and you will hear a tone one octave and a fifth above the fundamental. We call this note the second harmonic (or third harmonic in engineering terms). The diagram below shows this particular partial vibration.
Placing your finger above the fifth fret and plucking will give a note two octaves above the fundamental, which musicians call the third harmonic.
When we pluck an open string we actually combine all these harmonics, plus many more higher ones, with the fundamental, in various proportions. When we play a note on a fret, the same proportions of harmonic content apply, but to the new length. This means that the actual vibration of a string is quite complex, and it is this adding together of various harmonics in various amounts that gives an instrument its ‘Timbre’.
Now consider a wooden or metal bar. Its ends are not secured, but it still vibrates when we hit it. The fundamental vibration, as it vibrates side to side, looks like this:
You will notice that, as the ends are not secure, they are able to, and will, vibrate. The two points of the bar that are not vibrating are called a ‘null point’, or ‘node’. This means that they do not oscillate or vibrate, and it is for this reason that the bar is supported on the instrument at these points, as the fundamental will not be damped or restricted in vibrating by contacting the felt or rubber support.
If you take a bar off the instrument and play it while holding it in your hand, you will need to hold it at a null point, which is normally about a third of the way down the bar, between thumb and forefinger. Try holding it in various places to find the point at which it is loudest.
Now, to see how harmonics work in a bar, try the following: Using preferably a bass xylophone or metallophone bar, place your finger in the middle of the low C bar and strike the bar with a beater about a quarter of the way along. Alternatively, take the bar off the instrument and, holding it between thumb and forefinger in the middle of the bar on the top and bottom sides, strike the bar with a hard beater. You should hear a note 2 octaves above the fundamental, which is our first harmonic on a bar (not one octave as in the case of the string). If this note is not 2 octaves above, then this is not a well tuned bar, and signifies a badly made instrument (unless it belongs to an older style concert xylophone that was tuned in the octave and a 5th style of harmonic tuning, known as ‘quint’ tuning). Try hitting the bar in various places to find the point at which you get the loudest sounding harmonic. The harmonics would look similar to the harmonics shown earlier in a string, except that the ends are not fixed. It is possible to hear higher harmonics in a bar as well, by repositioning your finger on the bar, and striking the bar at various points. You will probably find that using a harder beater, ie one used for playing glockenspiels, will give rise to clearer sounding harmonics. These higher harmonics will have very little sustain, and would be hard to even pick up as a note. You might want to try playing harmonics on other bars. Try an alto xylophone, or even a soprano and see if you can hear the really high ones. This is good practice for the next stage of making your own bars, which will require finding and tuning these harmonics. High quality concert instruments pay close attention to tuning these higher harmonics as well, giving rise to the term “triple tuning” to indicate the tuning of the fundamental and the 1st and 2nd harmonics. For our purposes in dealing with classroom xylophones and marimbas however, tuning the 1st harmonic should be adequate.
If you did hear a first harmonic on a bar not quite two octaves above the fundamental, this could mean that the bar was not tuned correctly (even though the fundamental is in tune), or that the harmonic has gone out of tune more than the fundamental. This is one of the main factors that separate the good from the bad as far as bars are concerned. With some practice you will be able to hear these harmonics in the larger bars without damping out the fundamentals. A first harmonic that is sharp or flat with respect to the fundamental will sound ‘untrue’. Theoretically it reduces the volume of sound possible as the two notes will not be adding together efficiently (as they are ‘out of phase’). It is most important to remember this when we start making bars, as removing wood from various parts of the bar will affect the various harmonics. This is most important in the lower sounding bars, especially the bass, where harmonics are still well within the vibrating capabilities of wood, as well as being well within the hearing range of the ear. The harmonics in the higher bars tend to become so high that the wood simply cannot vibrate that fast, and so it will not be an issue, leaving us able to concentrate on tuning the fundamental only.
It is a good idea at this stage that you play around with various bars, of various makes if you have them, to hear the differences, and the extent to which the manufacturers have tuned the various harmonics to the fundamental. In my experience the bars used in the Studio 49 series 2000, the dark wood bars that have a curved surface, have performed the best. Suzuki bars generally work quite well, (though I have met a few that were a little suspect). Sonor (particularly the “primary line”) xylophone and metallophone bars however can be dreadful! Remember that it is the first harmonic above the fundamental that we are most interested in. You will also find that harmonics in Metallophones will be easier to hear. This is because metallophone bars have a much longer sustain, while also tending to have a ‘brighter’ tone. Instruments that have what we might call a ‘brighter’ timbre, usually have a greater higher harmonic content in relation to the volume of sound from the fundamental.
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CHOOSING WOOD FOR BAR MAKING
This is an area that is debated at length amongst instrument makers. What I have suggested here represents my thoughts on the subject at this time. Bars can be made from almost any type of wood, but some are better suited than others. In choosing wood, remember that the drier the better. I would also suggest using hard woods, (in fact the harder the better for most classrooms) and not using pine or any softwoods. A soft wood, for example well seasoned Oregon, will probably sound quite good but will tend to get dents in its surface after a few years in the classroom. This could give rise to tuning problems as the shape and density will change with this sort of punishment. You could always keep an eye out for odd bits of timber laying around your, or other peoples garages, that have been around for a few years. I have been known to rescue timber from old unwanted furniture, to see if it will work. The more I make bars from old pieces of ‘scrap’ that may end up in the firewood basket the more I am convinced that one does not need to buy those expensive imported timbers. Instead, try looking around building material salvage yards for some Victorian Ash (otherwise known as ‘Tassie Oak’) floorboards, or off cuts of Merbau decking. You only need one floor board to make some bars, and you need only buy lengths long enough for the longest bar you need, (as long as the thickness is correct) which may be too short for building purposes. If you buy a new piece of Merbau from the hardware, it may need to sit around for a while to dry out more, or just keep retuning it as it dries. Basically any dense hardwood is well worth trying, especially dense Ash.
When a flat plank of timber is cut from a round log in which the grain appears as concentric circles, the grain shown on the end of the flat plank will be determined by where it came from in that log. Timber for musical instruments in general comes from timber that is “quarter sawn”, and this is especially so with xylophone bars. It’s a bit beyond the scope of this booklet to discuss quarter sawn timber, but easy to investigate on the internet, or ask a timber specialist at a timber supplier.
Timber bought new at a timber supplier is often kiln dried (“KD”). This is fine for the building and furniture industry, but xylophone and marimba bars made from this will continue to go sharp as it dries out more over time. Not a great problem, but you might end up retuning them several times over their 1st few years of life.
To test a piece of wood, hold it by pinching between thumb and forefinger about a third of the way from one end (remember that null point) and hitting the wood with your knuckle or something that wont dent it. If it sounds ‘dead’, forget it. If the wood responds with a dull tone, it will work, but perhaps not to well. If it responds with a bright tone, or very loudly, it could be good. You can always pick the instrument makers in a wood yard. They spend lots of time picking up many pieces of wood, holding them close to one ear, knocking on them, and end up buying very little. I am sure yard proprietors find them amusing (at least I hope so).
When purchasing wood from a wood yard, test each piece (if it is small enough to handle) as suggested above. Look for pieces that are straight and have an even straight grain without any knots. Ask someone to explain what a quarter sawn piece might look like. If it is second hand timber, make sure it is free from nail holes in the parts you wish to use. I bought some Brazilian Rosewood many years ago. Regarded as the best timber for xylophone bars. This plank had some form of cross-grain that left little cracks when it dried. This sort of cross grain looks nice, but often prevents the wood from vibrating freely or evenly, and this plank was useless.
If you prefer to go the ‘new timber’ route, you might want to store it for a while, depending on how old it is. Unfortunately, the more suitable the wood (ie the denser it is), the longer it will take to dry out enough. A new piece might take at least a year or so to dry out enough to consider. There is very little literature available to the serious tuned percussion maker regarding types of wood for making bars. The following lists my experience to date, as well as that which I have read and learned from others.
Honduras Rosewood .
Also known as ‘Palisander’. This is the legendary and traditional wood used for making bars for concert xylophones. It is not the same as Brazilian Rosewood. It is used by Studio 49 in their Series 2000 xylophones, and Sonor in their better instruments. It is hard, relatively easy to machine and work with, beautiful in appearance and sounds as good as it gets. It is also very expensive, almost impossible to get in Australia, and listed as an endangered species. It is very critical that in purchasing this wood you choose pieces that have a straight and even grain. Avoid those nice wavy patterns, or anything suggesting knots.
This is not as hard, dense, or expensive as the Brazilian rosewood, but has given me excellent results. Its color will be close to that of most other bars.
New Guinea Rosewood.
This is similar to Malaysian Rosewood except in color. It has also given me good results. Its color is much lighter than other rosewoods, so might not match your other bars. Tends to be a bit soft for my liking.
The piece I tried worked well after it had some time to season. It is a very hard, relatively inexpensive timber that is also quite attractive. I was advised to be careful when sanding this timber as the dust can have some adverse effects. One story I heard was of someone machining this timber, passing out and waking up two days later. I would suggest working outside or having a dust extraction devise fitted to whatever you are using to sand.
Purple Heart. This is a relatively inexpensive and very hard wood, that sounds quite good. As the name suggests, it is purple in color. It is not easy to machine however, tending to chip on the surface as it goes through a thicknesser.
This is an Australian timber that I can recommend. It is hard, relatively easy to machine, and sounds reasonable. It is however very light in color. I have made replacement bars colored with Wattyl ‘Rose-Mahogany’ to approximate the color of rosewood bars, with good results. I might add that using an Australian Timber does have economic and ecological advantages.
I have however found it difficult to source this wood of late. It was used at one stage in wood flooring, but seems to have lost its commercial viability.
Highly recommended as a cheap source for good results. This is very commonly used for outdoor decking, and often available second hand. It also works well, and is easy to machine and sand. It sounds very good, but I do find that the tuning does not stay as stable as some other timbers, but then the variation tends to be very minor.
As decking it usually comes in thickness of around 19 mm, with or without grooves on one surface. Both types are fine. Merbau is usually a soft red in color, which leaches out if the timber is subjected to much moisture, so you may find some that is very pale. If you use second hand merbau, just check that it has not rotted in any part, especially around nail holes. Also look for merbau that has a straight grain that runs in line with the length of the bar. I have found that most timber, and this one in particular, sounds dreadful if the direction of the grain is running across the bar even slightly.
Merbau is available at many timber hardware stores. If buying it new, look for the harder red colored planks with the grain running in line with the sides as much as possible. If you find someone building a new deck, there is bound to be lots of off cuts available. If someone is removing an old deck than you may have more timber than you can use in a lifetime, and be choosy.
Brush Box. A very dense, hard timber that gave me good results. It is light in color, used in flooring as far as I know. It is also an Australian timber.
Currently becoming my favourite. Padouk comes in two different types. African Padauk, often called African Rosewood is very red in color. Burmese Padauk is more brown in color. Naming these timbers is often a little confusing. Some places seem to refer to the Burmese stuff as simply “Padauk”, and the African stuff as “African Rosewood”. When you sand this material it has a distinctive smell, and both types smell the same. I’m tending to prefer the Burmese variety these days, as it is a little harder. I recently was able to buy some nice quarter sawn Burmese Padauk that sounded simply stunning, and is as good as any timber I have ever seen, including the legendary Honduras Rosewood. It’s just not quite as hard. It does tend to be at the more expensive end of the pricelist.
Other timbers suggested in my reading on the subject are: Iroko, Hard Mahogany, Walnut, Beech Plane, Cherry, Pear, and any dense type of Ash.
None of the literature mentions Australian timbers, which I believe have excellent possibilities for making bars. This is most likely because xylophones hail from Africa, and continue to be made mainly in Europe, Asia, and America, as does any writing on the subject. We tend to have a range of dense Ash’s in Australia, all of which would be worth trying. Quilla, Hickory Ash, and Cooktown Ironwood are all worth a try if you can get them. These would be ideal as they are very hard and would be indestructible in the classroom. Blackwood, and N.S.W. and Queensland Rosewood is also worth looking at. Most Australian timbers tend to be light colored, so you may have trouble color matching something to your existing bars. I have used a ‘Rose Mahogany’ wood stain by ‘Wattyl’ on a light colored timber to match a Suzuki bar. I suggest avoiding the use of Jarrah. I have seen some bars made from this, and although they look great, they did not sound good at all.
The choice of timber is of course dependent on many things. Availability, color, expense and perhaps ideology. Although I have used imported rosewoods to make bars to match those on imported instruments, one might bear in mind that these timbers come from disappearing rainforests. We of course tend to use much less of this wood than do furniture makers, but if we use this material we do contribute to the problem. Using Australian timber may mean making bars from a light colored wood that is in sharp contrast to other bars on your instrument, but will work just as well, and may be cheaper. One can always stain the wood prior to varnishing.
MAKING A XYLOPHONE BAR
When you have acquired a piece of wood, you may need to reduce its thickness to match the other bars on your instrument. And then cut it along the grain (called ‘Ripping’) into lengths as wide as your bars. You will then need to cut off a piece the length of the bar you require. This may be difficult as you of course no longer have the bar to be replaced. Simply measure the length of the two bars either side of the one in question and cut a new one that is halfway in between. To drill the hole for the pin, do the same thing.
To reduce your timber to the correct thickness you will need a thickneser, or planer. And to ‘rip’ it to the correct width you will need a saw set up for ripping. A wood yard or woodworking joinery shop may be able to help you with all of this. Cutting off a piece the correct length can be done with a handsaw, but be careful as the result looks very ugly if not cut very cleanly. You may then want to take the sharp edges off the wood with some sand paper. Some Studio 49 and Sonor bars have a curved rather than flat top and bottom, as shown below.
To match this you will need a large disk sander or drum sander, or linishing machine, but this shape is tricky to match, and is not necessary as the bar will work perfectly well if left as a flat piece of wood. I suspect the reason for this shape is to allow for a better glissando. Moving the beater across a series of flat bars does not give as loud a gliss. as these curved bars.
Next, drill the hole for the pin. To determine the location of the hole from one end of the bar, measure the two bars either side of the new one and average out the measurement. Again you will need to measure the hole size in the other bars. Some bars have a hole the same size all the way through. Suzuki bars have a ‘stepped’ hole for the rubber on the pin to locate the bar, as shown below:
In this case you will need to drill twice. I highly recommend drilling the larger size first, and then carefully centering the smaller hole for the remainder. You will need a pedestal drill for this as a hand held drill is very difficult to control accurately, or to make a neat finish.
Once you have drilled the hole, you are ready to start removing wood to tune the bar. I use a linishing machine, or a belt sander placed upside down on a bench, for this. You could use a rasp, or surform file. The rasp and surform file should be fine, but I don’t recommend the hammer and chisel as it is hard to achieve a nice symmetrical curve in the underside of the bar, and a small bar is easy to split. If you do use a belt sander, be very careful not to start ‘tuning’ your fingers, as they will be close to the surface of the belt.
At this stage you should note that wood is not a homogenous material, ie it does not necessarily have a uniform density all the way through its structure. It is entirely possible that you may start sanding away at your bar, which seems to be doing all the right things, and then suddenly it goes dead. The piece of wood may sound dead to start with, although the rest of the wood from which the piece came seemed fine. If you find that suddenly it does not produce a note at all, it is most likely a fault in the wood, or rather, wood just being wood. Discard this piece and start again. Fortunately this does not happen often. I will assume for this first exercise, that you are making a bar for the middle of an alto, or for a soprano xylophone, in which we are tuning the fundamental only (and none of the harmonics). The bar should end up looking similar to the other bars on the instrument, in that the material will be removed in an arc underneath approximately 1/3 of the middle section of the bar.
You could start by marking the middle 1/3 section of the bar with a pencil. Now start sanding, or rasping, starting at the center, and making an arc that slowly extends outwards to the marks. As you go you will need to keep checking the tuning, which will gradually descend in pitch as you remove wood. I use an electronic tuner when I near the correct pitch and start taking of smaller and smaller amounts. If you take off too much, you can compensate by sanding off the ends, or by drilling large holes in the underneath as close to the end as you can. But this will only work to a certain extent. If you sand of the ends you may end up changing the length and may make it look out of place when on the instrument, as well as changing the null points so the bar won’t perform as well in it’s designated spot. To check the tuning you can hold the bar between thumb and forefinger where the hole is, or better still, place it on the instrument. At this point I find that once I have achieved the correct tuning, the bar tends to go a little sharp as it loses the heat generated by the sanding, so you might want to check it in ten minutes or so.
When you have tuned the bar correctly I would suggest not varnishing it for a few days. You may however start using it immediately if you wish. Check the tuning the following day. It may have changed, as the bar will have cooled down from the heat generated by the sanding. If it has, it is most likely still a bit sharp, in which case you can remove a little more wood to retune. It should not need much at this stage. If the wood was well seasoned you could varnish it now. If the wood came from a wood yard you might want to leave it for a while, and see if the tuning changes over a few weeks, and then varnish if it seems fairly stable.
Now let us make a bar for a bass or the first octave of an alto, in which we will need to pay attention to the harmonics. You will of course need to acquire a piece of wood the same thickness and width as the other bars. Bass bars are thicker and wider than bars on your altos and sopranos. Drill the holes as described above and we are ready to start. When tuning harmonics you will not necessarily end up removing an arc from the middle third of the bar. The harmonics will be tuned by removing wood in the middle of each half of the bar (i.e. from the edges of the arc, as shown in the diagram below, while the fundamental is tuned by removing wood from the center.
This means that the size and shape of the arc will be determined by the degree to which the harmonic responds to tuning. Examining some good quality bass bars, eg Studio 49 or Suzuki bars, will give you an idea of how large an arc you may need. It is entirely possible that you may end up with an arc taking up the center three quarters of the bar, extending all the way out to the locating hole.
To begin with, mark out the center third of the bar as before. Start sanding this area. At some point long before you reach the fundamental note, start checking the harmonic. As mentioned before, this is done by holding the bar between thumb and index finger in the middle, and striking the bar with a fairly hard beater. This harmonic should be tuned to two octaves above the fundamental. If you find you have two octaves above whatever the fundamental is at this point you would be fortunate indeed, and you could just continue as you were, removing wood from the center third. It is more likely that the harmonic will be higher than two octaves above the fundamental, in which case we need to start increasing the length of the arc. It is most important that you do this in equal amounts from the center. This means that the arc should always look perfectly symmetrical about the center of the bar. The best way to check for this symmetry is to play each side of the bar, ie, damp the bar in the centre and play the harmonics on both halves. The bar will tell you which side needs to have more removed as its harmonic will be higher.
You may need to remove wood all the way to the hole. If it looks as though you are getting close to it, in an attempt to get that harmonic to come down, it is acceptable to start making the shape look more like the following diagram.
You may notice that removing wood very close to the hole (and the corresponding point on the other end) does not have a great effect on the fundamental note.
Once you have the fundamental and the harmonic roughly ‘together’ (don’t worry if they are not exactly together at this point), you then have the right shape arc (more or less) for that bar. So removing wood evenly across it, widening the arc as needed, should bring both fundamental and harmonic down together. You may also find that damping the bar in the middle, and striking it on first one side, then the other, will give you slightly different notes (ie differently pitched harmonics). You could think of the bar at this stage consisting of two halves, each able to produce a slightly different pitch. If this is the case, you will need to remove a little more wood from the end of the arc of the half that has the higher pitch. This is getting very particular, and might sound difficult, but it all goes to making a better bar with a cleaner tone.
The science of tuning is a complex area, because it involves the human ear. Piano tuners are familiar with a phenomenon called “stretch tuning”. To keep it simple at this point, if you want to use an electronic tuner to tune your harmonics, that’s OK. If you want to tune the harmonics by ear, and they end up sounding sharp when subjected to an electronic tuner, then your ear is functioning correctly, as the human ear wants to hear higher pitches a little “stretched” or higher than actual pitch. Most instrument tuners will suggest the latter as it makes a more interesting and livelier sounding bar to tune the harmonic by ear. Either way you will end up with a perfectly acceptable bar for the purposes of a classroom instrument.
You may want to practice making a bar from a piece of wood other than that expensive piece of rosewood you ultimately wish to use. It would be a good idea to organize the practice piece when you are machining down the real wood as this would take little extra time to do. Be careful however, as differing woods will respond in different ways, so the size and shape of the arc may also vary from your practice to your final bar.
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REPAIRING TAMBOURS AND HAND DRUMS
These instruments have been discussed in the earlier section of this article. I will however discuss the replacement of skins here. If you have an instrument that has tuners to adjust the skin tension, then replacing the skin is simply a matter of undoing these tuners until they are loose enough to remove the old skin.
The skin is attached to a metal rim. This is then held down by a metal hoop to which the tuners are attached. What you choose to replace it with will depend on the brand. If the instrument is one of the cheaper Taiwanese types, it will probably be a plastic membrane attached to a metal rim. These ready made replacement skins are quite cheap to purchase and as easy to replace as they were to remove. They are available from most music shops. I have noticed however some variations in size in these replacements. I suspect that they have come into the country through more than one importer, and from at least two overseas manufacturers. I have often bought some of these replacement skins and found that they do not fit into the old hoop, being just a couple of millimeters to large. I have not been able to purchase the different size hoop to accommodate this replacement skin. I suggest taking the wooden rim and metal hoop to the shop with you to ensure that the metal ring on which the skin is attached fits into the metal hoop, and fits over the wooden rim.
The other option is to fit a piece of goat skin to the metal ring that holds the plastic skin. This skin is available from specialty drum shops, and from music shops who are prepared to stock it, or order it in for you. Skin, or velum may also be available from skin and hide suppliers, but I have not looked into this as yet. This skin is not fitted to a metal or wooden ring, known as a ‘flesh hoop’, so it will need to be fitted to the old one. This option will cost more, as a piece of goat skin will cost more than the plastic, and require more work in fitting, but you will have a superior instrument that will sound better. Proceed as follows:
1) Remove the old plastic skin from the ring, with a knife. This ring will hold the new skin.
2) Obtain a new piece of goat skin about 60 millimeter greater in diameter than the metal ring. Soak this skin in water, preferably lying flat, for no less than one hour before proceeding.
3) Lay the soaked skin on a bench. Place the metal ring on and in the center of the new skin.
4) With a number of clothes pegs at hand, commence folding the edge of the skin over the ring, attaching a clothes peg so that the skin is pegged around the ring onto itself. Using that part of the clothes peg that normally fits around the clothesline the skin should fit around the ring neatly. I find it is best to start by making one fold, followed by one diagonally opposite. Next, fold one in between the two, followed again by one diagonally opposite. Continue like this. It will be difficult at first to avoid creases or folds around the edge, or in the material that is folded around, but these are not a problem as long as they are not to big. The more pegs you use, the better the skin will be wrapped around the ring. Do not try to stretch or slacken the skin. It should remain flat but not tensioned, without any large undulations across the center.
5) Place all this where it can start to air dry. Do not place in front of the heater. As it starts to dry, it should start to acquire a dull ‘tone’ when you play it. But do not let it dry completely as it may remove itself from the ring when you remove the pegs. This is because the skin shrinks as it dries. Proceed to the next stage when the skin has dried enough to keep its shape long enough to transfer to the wooden rim.
6) Remove the pegs, place back into the metal hoop (with the folded over section of skin facing so as to come into contact with the wooden rim), replace on to the wooden rim and replace the tuners. The tuners should only be tensioned enough to keep the skin firmly in place. The skin will dry and shrink more, and so will tune itself over a couple of days.
7) After a few days you can retune as needed
I have found that replacing in this way will not require any further tuning when the skin has dried completely. If you do want to adjust the tension higher it must be done with caution, as the metal and wooden hoops on these cheaper instruments, into which the skin and metal ring sit are not very strong and certainly not designed to take the tension of this thicker material. If it sounds OK, leave it. If it sounds to dull, tension it slowly, keeping an eye on the metal hoop, ensuring that it does not start to bend. If this happens you might find the skin and ring will try to find their way out from under this hoop. If you have one of the better hand drums, or tambourines, eg a Studio 49 or Sonor, you will not be able to replace it with a cheaper plastic skin as mentioned earlier, as they are unavailable for these instruments. It may be possible to find a proper replacement skin, already attached to a wooden ring. These are easy to replace, but must be soaked for at least half an hour prior to replacing. I have not seen one of these for a while however, and have resorted to simply replacing them with a piece of skin in a manner similar to that described above. The main difference with these instruments is that the hardware is stronger, and more able to withstand the greater tension required to tune goat skin to a good tone. Normally these skins are formed around a wooden flesh hoop. To remove the old skin, soak it for a while, which causes the material to loose its shape. It will now come of the flesh hoop very easily. Fitting the new one is the same as described above, except that you might try to leave some slack in the surface of the skin, so that it will curve over the top and down the side of the wooden rim enough to allow the top edge of the metal hoop to which the tuners attach, to come down so as not to stand above the wooden rim. This means that you wont strike the metal rim when you play the instrument by hitting it near the edge.
Non tunable Hand Drums and Tambourines
Those instruments that have skins attached by thumb tacks or some other non-adjustable means will require a piece of goat skin and attach it as follows:
1) Remove thumbtacks and old skin.
2) Obtain a piece of skin large enough to cover the top plus go down the side of the instrument on both sides. You could measure the old skin if possible. Soak the new skin for at least an hour.
3) To replace the new skin, place it centered over the wooden rim, in place of the old one. Fold down one edge and place a thumb tack through the skin, into the wood. Now do the same diagonally opposite. Keep the skin straight without actually stretching it. Now fold and pin down one edge in between these two, followed by one diagonally opposite. This second pair should enable the skin to be held in place without any large undulations in the skin, ie one pair of diagonally opposite pins should not be exerting more tension than the other. Continue in this manner, folding down in between two pins, followed by another diagonally opposite, until you have replaced the original number of pins or tacks. The skin will not have any tone now, but should sound OK when it dries in a couple of days time.
If you have one of these instruments with a skin still intact, that just sounds dead, it is possible to simply replace the original skin, as outlined above. The reason it has lost its tone is that it has been played to hard, with the skin repeatedly stretched beyond its ability to return to its normal tone, or been in a hot environment, like a car on a sunny day. The skin may be used again however, after being soaked for an hour or so, and reattached as above. Some people suggest that these instruments are better than those with tuners as the tuners add more dead weight to the instrument, stopping it from vibrating or ringing freely. This is quite true, and all very well when they are played within their limits, ie properly and with respect, but the argument does not observe the realities of the average classroom, where at least one student is testing the limits of both teacher and instrument. For this reason I recommend the adjustable or tunable ones.
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LIST OF SUPPLIERS
Repairs to most Orff style tuned and non-tuned percussion instruments. Repairs to orchestral tuned percussion. Able to supply rubbers, pins, and bars for a range of brands.
Web site: www.musaics.com.au
Ph: (03) 9754 3470, or 0422 176 438 (Melbourne based)
Importers of Sonor instruments and spare parts.
Ph: (02) 636 7111 (Sydney based)
Optimum Percussion. Importers and distributors of Studio 49 and Optimum Percussion brands, as well as heaps more. Good for parts etc. (Sydney based).
Stockists of a range of timbers suitable for making bars. Unable to machine timber to suitable thickness and width unless you require this in large quantities. (tended to be unhelpful) but they have racks of labeled timber you can look through. Ph: (03) 9874 1666 (Melbourne based)
Stockists of various rubber tubing etc suitable for replacing rubber parts.
Aqarium Shops. For silicone tubing suitable for replacing rubber tubing supporting bars. Just ask for “Air Tubing” or “Aquarium Tubing”.
Your local music shop. They should be able to order in parts for you, especially things like pins for Suzuki instruments, parts for Optimum or Sonor instruments etc.
Premier Vibraphone Electricals
Premier vibe speed control
This is the circuit diagram of the speed control used on the Premier 751 vibraphone. Possibly used on other vibes as well. This is a very crude way to speed control a motor, but I guess it works well enough for a vibraphone. The main problem here is that the variable resistor, or potentiometer (pot) gets very hot. According to the printing on the one pot I had here, it is rated at .05 amp, which at 110 volts suggests its handling at least 5.5 watts.
I have had a few of these vibes that burn these pots out. Probably should be replaced with a 10 watt pot, if such a thing exists. I made up a speed control like that shown in the circuit. Worked fine, but as I was only able to get a 4 watt pot, it was getting really hot!
The motors that were available in Australia were made in he US by Bodine. Type KCI-23A2. I recently contacted them. These motors are still available, and the people I emailed there were very helpful. Apparently these motors were used up till sometime in the 1980's. After that a Cintenco motor was used. I have no information on this motor as I haven't seen one here as yet. Appreciate any information re this motor.
The transformer used on the 751, and possibly other vibes is a dual primary transformer, that allows the instrument to be used with 240 or 110 volt power supplies. The voltage needs to be switched by taking off the cover to the transformer box. The box also contains a fuse, buried inside.
The switch used in this transformer box has connections that are way to small for the voltages and size of wires used. If a transformer is found to be not working, and probably blowing fuses, it's most likely because the soldered connections to the switch have simply let go. I had a brand new transformer here that was blowing fuses. Pulled it apart and found most of the soldered connections had simply let go. It looked like it had been soldered by junior high school student with a soldering iron from a wheaties packet!
Best thing here is to bi-pass the switch. Just hardwire it for your countries power supply.
If you have 240 volt power than the orange and yellow wires should be joined, and the supply voltage can be across the brown and blue wires.
If you have 110 volt power you don't actually need a transformer at all, but you can join the brown and yellow wires together, and the blue and orange together. The 110 volt input can then be connected across these 2 pairs.
PLEASE BE WARNED! Don't do this unless you are pretty confident about your soldering and handling of high voltages like this. This is serious stuff. It is no exageration to say that people die when one gets this wrong.
Concert Xylophone and Vibraphone Bar support Rubber Replacement
In this section I discuss a method I have devised for replacing the rubber sleeve that covers the metal post that supports the string that threads through the bars. This is usually a rectangular sleeve, that cracks and falls off with age. A very similar size sleeve is used on many brands of xylophone and Vibraphone. I devised this method as I was no longer able to obtain Saito replacements, as they have folded. These type of rubbers are also used on Korogi, Yamaha, Musser and probably others. Please note this will not work on Premier instruments. Premier use a different system that requires a speacially moulded rubber post, that is very difficult to obtain.
I have used a material called "heat shrink" plastic. This is usually available from DIY electronic shops. For the Saito I repared I used 19 mm dual wal, as shown in the photo. The size you use may vary, depending on your instrument.
This dual wall stuff is thicker than the standard heat shrink, and also has a glue inside, that melts and glues when it is heated. One simply cuts a piece that is long enough to cover the part of the bar below where the string sits on the metal support, and place it on the bar as shown in the next photo.
For the next bit you get out your heat gun. Oh, forgot to mention, you'll need a heat gun. This is an item similar to hair dryer. Except the air that comes out is a little hotter. These are usually fairly cheaply available at places that sell power tools.
Turn on the heat gun to its highest setting and bring it right up to the heatshrink, and it will shrink around the metal post in around 2 seconds, and look like this.
This one application is probably enough to work well, as it will stop the bars from buzzing against the metal post, but I do like to use 2 layers as this better approximates the thickness of the original rubber. So, just do the same thing again, and it should look like this.
Do this to all the posts and there you go!
I found I needed 2 one meter lengths of the heat shrink to do a double layer on each post.
If most of the original rubbers are still in place, but just cracked and about to fall off, It should be fine to use a similar size standard single wall heat shrink around the old rubber, and hit that with the heat gun. Better than using tape as I have often seen used.