Planning to Build a Marimba? #2

----- Original Message ----- 
To: jim@percussionclinic.com
Sent: Thursday, February 21, 2002 4:31 PM
Subject: Marimba Building question

I saw your website and I'm very much interested in building a marimba. I had a couple of questions, regarding bar sizes to use, say for a 4 octave instrument, I noticed that the bar sizes from many of the big companies like Musser, start at 2 1/2 inch wide down to 1 1/2 inch wide. my question is are they all slightly narrower or are certain ones the wide size, then jump to the narrow size? and if so, where do you begin the narrow ones?

Also, regarding the layout of the bars, how much space do you leave in between the bars side by side. also, how much do you overlap the incidental row with the front row.

Many Thanks,
Jim

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The width of the bar primarily affects the amount of energy the bar can produce. Wider bar means louder sound for a given resonator. Wider resonators are also louder, but they do this by taking energy away from the bar more rapidy. So if you have a wide resonator under a narrow bar, you will find the note is short in duration, as the resonator literally drains the bar of its vibration. Part of the trick is to match the bar width to roughly that of the resonator diameter. So it will depend a little on what you are using to construct your resonators.

All marimba makers tend to have differences in how they graduate the bar width. In general you will find you can use the same width for about four to seven bars in a row. This is more practical, as you can get the width of plank you need, then just cut the lengths you need. The difference in width is less important in the upper register, but as you get lower, you will find that you only have a small group of same width bars. This is because human hearing ability drops off exponentially as we go lower, so as you go to the lower notes, they have to start producing more energy to compensate, so our subjective ears hear it as the same volume as the higher notes. This means obviously then, that the more graduated the widths of your bars, the more the apparent evenness of volume produced over the range of the instrument.

As regards the layout of bars - the answer to both questions, is "as little as is practically possible". In general - the smaller the gaps, the easier the instrument is to play quickly. 12-15mm is usually about right between bars to fit in a string holder surrounded by some rubber tube or whatever. Between the upper and lower registers. There should just be the tiniest of gaps between the long support timber which holds the upper row of bars, and the end of the bars in the lower register.

Hope some of that has been some help - feel free to ask some more if you need - good luck!

Jim McCarthy

For more help on marimba building you can email Jim.

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