Overtone Placements on Bass Marimbas (Discussions with Chris)

-----Original Message-----
From: Chris
Sent: 26 August 2008
To: jim@percussionclinic.com
Subject: Bass Marimbas

Thanks for posting so much info on marimba building. I am a builder myself and have gotten lots of help from your site.
I have a question about harmonic tuning. When you make super low bass notes, how did you tune the harmonics? Did you still tune them with an octave and a major 3rd? I have been experimenting with tuning the 3rd harmonic to an octave.
Doesn't tuning the bars with a maj 3rd cause conflicts while playing other notes?
I am wondering why marimbas aren't just tuned with all octaves so there would be no conflicts.

Any help would be great
Thank you

Chris

Hi Chris - Thanks for your email.

I love your photos - you achieve a very professional looking finish!

It's an interesting topic you present, and one which I've thought a lot about myself in years past. I've always tuned the bass instruments the same - fundamental - 2 octaves - 3 octaves+3rd, BUT I agree that as you start to go lower, it makes less sense to do so. I'm talking pretty low of course, before a change would be appropriate in my opinion - but I've often considered making some more bass instruments and trying some ideas along those lines. I've even considered building a contra bass double resonated instrument - the harmonics would be at either 2octaves then 3octaves or at 1octave then 2octaves. A second resonator would be tuned to the first harmonic and be positioned under its antinode. One day - one day!

In a standard instrument - even a fairly low one - you don't really get conflicts with the 3rd mode at a third. It's relative intensity and duration are so small that it's contribution to the overall sound of the note is more one of quality than pitch. The standard harmonic positions have been chosen with two considerations - one - as you are thinking - to be musically close to the fundamental. Two - to be one of the notes which DOESN'T resonate in the tube. The idea is to have a stronger relative fundamental.

For super-low notes - and once again I'm talking really low here - there may well be a justification for making it different. The idea I wrote about above came about because of this very issue of the increased role the harmonics play in the actual sound of the note, and in particular its perceived pitch, when dealing with very low notes.

The essay I wrote years ago (you may already have read it) has a bit to say about this. It's here:
http://www.percussionclinic.com/art_mbasa.htm

All the best.
Jim McCarthy

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