Materials and tuning for Vibraphone bars (Qs from Josh Ryan)

-----Original Message-----
From: Josh Ryan
Sent: 24/01/07 8:50 AM
To: jim@percussionclinic.com
Subject: Instrument Building

Basically, I understand that vibraphone keys are made from aluminum, which I can get, cut to the specific size and shape. I got a scrap piece of the aluminum to test (1/2" thick with a 2" width, about 4" long) and placed it on felt and stuck it with an assortment of mallets and I received no tone. The idea of a vibraphone key seems pretty simple, I just don't understand why I'm not getting a nice ringing note. I just get a dull, flat "donk" sound. Does the underside need to be cut out in a curve to allow the aluminum to vibrate more? I was told all aluminum is more or less the same density and substance, but is it possible I'm using the wrong material somehow?

If this question is beyond your realm of expertise, would you be able to point me in the right direction? Thanks a lot,

Josh Ryan

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Firstly the question of materials - well its true that aluminum is aluminum as far as it is the 12th? Element on the periodic table. There is of course an almost infinite number of alloys - being combinations of aluminum with other metals. The manufacturing process will also make a difference - ie casting vs extrusion etc. The metal most vibraphone bars are made from is similar to a high-copper alloy called duralumin which is what they make aircraft wings from. Pure aluminum can make a decent tone in a bar shape, but the copper and other metals makes it harder and denser which makes it ring more and also allows it to withstand the beating without going out of shape.

As far as the shaping of the bar is concerned, a vibraphone bar is tuned in much the same way as a marimba bar - so there should be plenty of information to get you started on the website articles. In fact the tuning of the 2nd and 3rd partials is probably even more important with vibraphone bars as they have more sustain.

Of great importance is the position of the nodal point - you will certainly get a very dull thud if you are preventing the bar from vibrating (holding it) anywhere except the exact nodal point.

I hope this has helped a bit with your questions mate... All the best....
Jim McCarthy

For more help on instrument building you can email Jim.

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