AMI Blog


This blog was originally part of a follow up letter to our marimba customers after Christian and Ben did a tuning and maintenance trip. Ben wrote the first draft, Christian fine tuned the technical information, and Mandy edited.

It’s interesting that in different parts of the country the AMI marimbas to be in better or worse condition – which suggests an overall ethos of playing and care in each region that is reflected in the condition of the instruments. Some sets have really had a beating, while others, that may be older and just as well used, are still in great shape. At some schools, the marimba players have got into bad habits and there are plenty of broken notes, broken mallets and other problems. It’s worth remembering that there is a point at which a note cannot get any louder – belting it harder will just end in damage.  

The difference between well used instruments and abused instruments is easy to see when you are the one who built them in the first place. Whilst some damage and wear could be attributed to overly exuberant and damaging play, most of what we come across is good old wear and tear from a lot of traffic over the years and probably the making of good music! (That’s why we make musical instruments after all!). While we do find abused marimbas, the ones that have been treated well are really gratifying to us – because they seem to get better and better with age.  We really enjoy seeing our customers as we travel around the country on tuning and maintenance trips and we believe that the time we put in to retuning and servicing, and listening to our customers, is what sets our marimbas apart.

Because we believe that information is power, we wanted to share some of the problems we commonly find on our trips. African Musical Instruments has developed their range of instruments with the following goals in mind:

Robustness – some 14 years back the switch was made from wooden to steel frames and there is no doubt that this has made the instruments less susceptible to damage.

Serviceability – components have been carefully chosen to ensure that a certain amount of maintenance can be carried out with items easily available from the local hardware store. By way of an example, 6mm gutter bolts and 6mm wing nuts were chosen as fasteners as they are stocked by all hardware outlets. Our stringing convention allows damaged notes to be replaced by simply cutting and replacing the cable tie holding the broken note. The replacement note can then slide into place and be fastened by a new cable tie – a simple efficient system. So, if you have a dead note, we can send you a replacement which can be slipped into the keyboard with the help of a clipper to snip the cable tie, and a new cable tie to hold the note in. The 3.5mm cable ties are also easy to find at hardware stores.

Cracked notes can be repaired with superglue, and while we are on our trips we do glue cracked and broken notes as a temporary fix. But these repaired notes have a good chance of failing again, so do keep get in touch if you need them to be replaced.

Tuning – resonators and notes are tuned with much care to ensure that the instrument is as sonorous as possible. In particular, on lower pitched notes, we spend substantial time and care on tuning a second frequency, or partial (often referred to as an overtone), which sounds two octaves above the fundamental note. It is relatively simple to retune the low fundamental pitch. However, without knowledge, understanding, and sophisticated equipment, the overtone tuning which took painstaking dedication to achieve, can be permanently ruined. We use a calibrated stroboscopic tuner, which allows us to see and control both frequencies as we bring the note to pitch. A basic guitar tuner or software-based cellphone app does not have this capability. Anyone looking to hire someone to tune instruments needs to be aware of this.  In the wrong hands notes can be retuned without the requisite knowledge, leading to damage that cannot be reversed. We are aware that outside parties have tuned AMI marimbas and it is really depressing to find instruments whose overtone tuning has been obliterated. If one note is beyond repair, then the only thing to do is to replace it. But if this happens to an entire set, the cost of restoring the instruments to their original partial tuning convention is substantial. Most institutions just have to live with the problem as replacing an entire set of notes is just too expensive.

Stringing – The method AMI has adopted to attach the notes to the marimba frames has been tried and tested for centuries throughout Africa. If strings break, it is fairly easy to replace them following the existing method.  Once again, the braided polyester chord (3mm and 6mm) is usually available from hardware stores. Two tips that will give you the best results are that the support chord (6mm) should be kept tight, using the mechanical tensioner, but the attachment string (3mm) should not be too tight. This allows the note bars to vibrate without restriction. We have seen elastic (which is used by other manufacturer), used on AMI instruments as a DIY fix, but this will only dampen the notes. The use of elastic as a replacement for string on AMI marimbas reflects a lack of understanding of how this affects sustain. We do find sets that have been restrung contrary to our conventions. If stringing conventions are changed it is time consuming to redo the stringing correctly and this makes our ultimate maintenance work more costly. Another problem is that the different stringing pattern usually prevents the possibility of notes being quickly removed and replaced without the restringing of the upper string. So, this also slows things down considerably.

Some other issues to think about:

Storage-wise, marimbas prefer environments with fewer fluctuations in heat and humidity. The bigger these fluctuations, the greater the chances are that they will go out of tune. High humidity is the biggest enemy. Wood absorbs moisture and the greater the exposure to high humidity the greater the chances are that instruments will go flat. The remedy, sadly, is not to simply retune the instruments, because the notes will sharpen as the atmospheric conditions change and they dry out again. If you are aware of notes going flat, it is best to try to find a drier environment where they will need to remain (We know how tricky this can be in a school or church). Be on the lookout for mould and corrosion – a surefire sign that humidity is too high. We are often asked about cleaning the instruments. A wipe down with a small amount of furniture oil is all that is required. Some marimba sets are kept covered with soft fabric covers – and this, of course gives extra protection, but is not necessary if the instruments are generally well looked after.

A last word on spaces – You also need to be aware of the acoustics of your playing space. If the marimbas are too loud during practice, the removal of the resonator boxes will be a drastic way of bringing down the decibel level. Softer mallets are a good starting point if you need to turn down the volume. In a very live venue, do consider ear protection.

We are proud that our AMI marimbas are known to be the best instruments available in South Africa in terms of their robustness, their sound, their portability, and their versatility. Our manufacturing conventions have been developed over 40 years with our experience in manufacturing bar percussion, first with Orff Xylophones and then for 23 years making marimbas. The proof is in the sound.