When you get problems with the sound quality of your marimba notes, there may be several reasons for this. It could be a simple issue that can be fixed immediately, or the marimbas could need to be tuned.
One surprisingly common reason instruments sound rubbish all of a sudden is that the resonators are the wrong way around. The tallest edge of the resonator box needs to be under the lowest note on the marimba. AMI marimbas have removable resonator boxes (whether they are wood or PVC pipes) that fit beneath the keyboard. Sometimes, in the rush of band life, the resonators can be fitted back to front. This completely ruins any possibility of the resonator doing its job. The lower instruments in particular will just sound dead if the resonators are on backwards. Part of the reason AMI instruments sound so good is the relationship between the note and its resonator. So, all you have to do in this case is turn the resonator around.
Notes can get a crack that results in the note sounding dead. Cracks can be due to a flaw in the wood, in which case, AMI will replace it for you. Cracks can also appear from harsh playing, or because someone leans or sits on the instrument (It happens…). Sometimes a bit of superglue squeezed into the crack will give you a good (and certainly temporary) fix.
Marimbas need to be tuned. New instruments will adjust to the atmospheric conditions of their environment, so AMI offers the first tuning service for free. After that, a tune and service every year is about right. Please, please, please, be cautious about who tunes your instruments. We cannot emphasise this strongly enough. AMI has a sophisticated tuning process that is not widely used, and several bands have had the unfortunate experience of a less subtle tuner working on their instruments, resulting in the loss of key overtones in the tuning. Once this has happened, the tuning cannot be reversed. AMI aims to be in each main centre and province at least twice a year, so make sure you get your name on the list for their next trip to your area.
The next common issue with good sound quality are the buzzer holes. Buzzers are optional on AMI marimbas. However, if your resonator box fronts have holes in them with red/brown plastic nipples, these are meant to be covered with plastic membranes. If you leave them open, you mess with the resonator. If you don’t want the buzz, but have buzzer holes, then just block them up. Corks would work, but an effective way to do it is to break expanded polystyrene packing material into chunks that are a bit bigger than the buzzer tubes, and force them in. You need to actually seal them to stop any air escaping. We love the buzz, but we get that not everyone does. If you want the buzz – cut circles out of plastic shopping bags and secure them over the nipples with O-rings. AMI can supply these, but you can also buy them at your local hardware.
Next issue: The room the instruments are in plays a big part in the quality of sound. If the room is too small, you will all need ear protection. But it gets a bit more complicated because sometimes the placement of an instrument in a room, particularly one which relies on tuned resonators for amplification, can radically affect the sound that each note makes. You know that if you sing in a bathroom or shower, sometimes you hit a certain note that really reverberates with the room and your position in it. This is something that affects marimbas and another bar percussion as well. Some notes in a particular space will sound very loud and sustained, while others may be affected by that destructive interference that we learned about in school science. In particular, the acoustics can mess with the upper and lower pitches – you can lose the bass entirely, or it can be quite overpowering. Try relocating your marimba and see if this helps. And keep working on getting a great practice space to house your instruments.
Another thing to check if the sound is not great is the supporting strings. If they are too tight, the keys will not be able to vibrate freely. Obviously – the string must be firm enough to hold the notes in place, but the string and the cable tie that holds it in place must leave enough bounce for the note to stay in position, but to free to vibrate. The pic above illustrates this well. This way you get your lovely resonant note with a corresponding sustain.
Loose strings are equally problematic as the notes need to be suspended so that they don’t clunk against anything when played. Clunking will quickly lead to breaking, so do deal with broken string promptly.
Like all instruments, especially ones that are made of wood, marimbas get better with age. As they age and are played in, the wood settles and there is no doubt that they get better with time. We’re not sure of the scientific reasons for this, but it may be that the structure of the wood changes after it has been played a lot, or perhaps it’s something to do with the wood stabilising to local ambient temperatures and humidity. The older the marimba, the sweeter it sounds, and the better the notes sustain. The great news is, AMI marimbas will last decades if they are well treated – so you can look forward to years and years of beautiful sound from them.