Helmholtz resonance values for ukes?

ichadwick

Well-known member
Joined
May 1, 2008
Messages
3,848
Reaction score
21
Location
Collingwood, ON Canada
Any luthiers here know the range of frequencies for the Helmholtz resonance in various uke sizes?

Does anyone here actually use the Helmholtz values when building a uke?
 
No - there's no point. It applies to bowed instruments which work differently from others.

Well, it actually applies to any instrument that has an enclosed body cavity. There's quite a body of work on the building of and physics of guitars in relation to the Helmholtz resonance factor. It's quite noticeable in a guitar - simply slide a piece of paper over the sound hole whole playing the low notes and you'll hear the difference. I can hear it on my ukes, albeit considerably less so than on my guitar.
 
Helmholtz resonance can be demonstrated by blowing air across the mouth of a bottle to create a tone. Same thing can be done with an air compressor blowing a stream of air across the sound hole of an uke. (I discovered this by accident while blowing debris out of the sound box.) My tenors tend to resonate at G.
You're welcome for this useless tidbit of information!
 
Helmholtz resonance is affected primarily by the volume of the sounbox and the size of the sound hole. My tenor design has remained the same for many years and I have not experimenting with these variables.
 
Ha ha! Chuck, your comment about the air compressor made me chuckle. Sometimes we do the same thing across the shop, but not to check the Hemholtz resonance. Basically, we're just screwing around and start making calls to each other using the air gun and uke bodies.
 
I just picked up the Peterson Strobosoft software a couple of weeks ago. The body resonance of a mahogany soprano just being finished is D4, -19 cents. To answer a question in the thread, if the resonance of an instrument lands exactly on a note, that note or chord is going to sound much louder than others. It is my understanding that you want to be somewhat sharp or flat from any semitone.

Brad
 
Top Bottom