WTT: What's the effect of wall thickness?

Jerry Freeman · Post by **Jerry Freeman** » Thu Sep 04, 2003 10:00 pm

Alright, you guys.

Now I need to figure out what the heck you're talking about. Is there a book or Internet source that explains the dynamics of whistles and/or wind instruments in general?

Thanks for all your help.

Best wishes,
Jerry

Zubivka · Post by **Zubivka** » Fri Sep 05, 2003 3:50 am

Daniel_Bingamon wrote:Yes, Closed hole correction becomes a big factor in thick walled whistles.

It also lowers the local cutoff frequency of each hole. This causes the sound radiation pattern to change at lower frequency. You can compensate by using wider toneholes. This causes wider spacing and therefore encourages the builder to make conical bores to keep things within reach.

Isn't the undercutting of holes, and/or their bevelling from outside, another cure?

Just as one example, the "pignose" holes of recorders are minute compared to the wall thickness, but they're set deep in a cylindrical cut-out reducing the local wall thickness. It rather seems to work: most decent recorders will play correctly the C#, one half-tone above bell, through a minuscule hole.
To compare, I'm yet to find a whistle sounding a good half-holed, low-register, D# without a buzz...

CHIFF FIPPLE · Post by **CHIFF FIPPLE** » Fri Sep 05, 2003 4:26 am

Thomas-Hastay wrote:Jerry wrote:"Whats the effect of thicker or thinner walls on behavior, timbre etc."

Using deep toneholes allows the designer to bring the fingerholes closer together in a keyless design because each tonehole is a "bore lengthener". One example of this use would be the last tonehole in a low whistle, to move it closer to the voicing without losing "apparent length".

Had anybody ever wonderd why Shaw Low whistles have what look like shoe eyes in the tone holes :roll:

Tony · Post by **Tony** » Fri Sep 05, 2003 4:38 am

Metal eyelets:

Zubivka · Post by **Zubivka** » Fri Sep 05, 2003 5:33 am

Tony wrote:Metal eyelets:

So that's a Shaw Low D?

Looks like these eyelets on L3, R3 holes will allow to bring them up, reducing the finger spread.
Makes sense on a low D, esp. for right hand strain.
And this right hand hole pattern does look both unusual and comfy.

Tony · Post by **Tony** » Fri Sep 05, 2003 5:52 am

Zoob,
I'm not implying the Shaw has eyelets... I was puzzled by Stacy's comment and found a closeup of the low D. It appears (to me) to be a raised area or a 'formed ridge' around those tone holes rather than normal drilling.

Jerry Freeman · Post by **Jerry Freeman** » Fri Sep 05, 2003 6:21 am

Zoob is correct.

Dave Shaw has intentionally used the chimney effect to bring the bottom holes for each hand closer to the other two holes. Those eylet looking things are the top, flared over surfaces of little tubes that extend into the toneholes.

Best wishes,
Jerry

P.S. Stacey, I think you knew that, right?

Jerry Freeman · Post by **Jerry Freeman** » Fri Sep 05, 2003 6:30 am

Still waiting for that reading list.

*Drums fingers.*

Martin Milner · Post by **Martin Milner** » Fri Sep 05, 2003 6:57 am

The thicker the wall, the faster you decelerate when hitting it in a car.

serpent · Post by **serpent** » Fri Sep 05, 2003 7:54 am

Jerry Freeman wrote:Still waiting for that reading list.

*Drums fingers.*

This subject was discussed almost to death, including the issue of internal chamfering amd the Coanda effect, a few months back in a WTT article string. I don't know of any comprehensive discussion in a book, though. Careful analysis of Pete Kosel's "flutomat" code (very clearly written in Javascript), will give you some insight into the mathematics for straight bores. Pete hasn't obfuscated the code, and has named variables reasonably, and provided good comments. A great exercise for someone more a mathematician and physicist into fluid dynamics, would be to modify his program to include tapered bores. Probably provide months of fun for someone so inclined!

serpent

Jerry Freeman · Post by **Jerry Freeman** » Fri Sep 05, 2003 8:03 am

Thanks, Serp.

That's helpful. I'll look into the old WTT threads again. In the meantime, I'm wondering if anyone could provide definitions for some of the technical terms, especially in Daniel's and Thomas' posts?

Again, I'm very appreciative of your help.

Best wishes,
Jerry

serpent · Post by **serpent** » Fri Sep 05, 2003 9:24 am

Jerry Freeman wrote:Thanks, Serp.

That's helpful. I'll look into the old WTT threads again. In the meantime, I'm wondering if anyone could provide definitions for some of the technical terms, especially in Daniel's and Thomas' posts?

Again, I'm very appreciative of your help.

Best wishes,
Jerry

Hi again, Jerry!

Remember, my friend, you asked for this!

http://ccrma-www.stanford.edu/CCRMA/Cou ... winds.html

You are gonna be soooo sorry!!! (I know I am! Now I got more homework to do. Thanks a lot, you kniggggggett!!)
Cheers,

serpent

Jerry Freeman · Post by **Jerry Freeman** » Fri Sep 05, 2003 9:55 am

*Sigh*

Well, I AM glad I asked. If there's more stuff like that you know of, please let me know.

Best wishes,
Jerry

Thomas-Hastay · Post by **Thomas-Hastay** » Sat Sep 06, 2003 2:17 pm

http://www.phys.unsw.edu.au/~jw/fluteacoustics.html

http://www.phys.unsw.edu.au/~jw/woodwind.html

http://www.phys.unsw.edu.au/~jw/fluteac ... .html#cork

http://www.phys.unsw.edu.au/~jw/fluteac ... tml#cutoff

http://www.phys.unsw.edu.au/~jw/WOLFE.pdf

Jerry Freeman · Post by **Jerry Freeman** » Sat Sep 06, 2003 2:50 pm

Thanks, Thomas.

As always, I very much appreciate your help. Great stuff.

Best wishes,
Jerry

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WTT: What's the effect of wall thickness?

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