[CAUT] Anechoic chamber - experiments

[Jim Busby]

Fred,

Most excellent suggestions! David Stanwood (months ago) said I could have some of his adjustable flanges (grams), and you've hit on a number of things that are "must do". Please see some things interspersed below;

Jim

From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Fred Sturm
Sent: Friday, June 18, 2010 1:35 PM
To: caut at ptg.org
Subject: Re: [CAUT] Anechoic chamber - experiments

On Jun 18, 2010, at 12:12 PM, Jim Busby wrote:


If any of you have ideas of things you might like to see studied, please let me or Keith know.

Some ideas:
The nitty gritty on mated versus unmated hammers. Hammers can be "unmated" easily and precisely by using Andre Oorebek's plexiglass device (narrow strip of sandpaper on plexiglass, so you can see precisely where you are filing). So you could make changes while leaving the hammer and strings in precisely the same place. Mate 3 strings, 2 strings (other one high), one string (others high) and see what that does. (Yes. Definitely)

Travel: de-travel a hammer significantly (you would need to make sure it hit the strings with the same part of the hammer) (I've been told at Yamaha that this makes a difference, but then why do some Hamburg's travel whole sections on purpose and they seem to not change in tone? We could test)

Square of hammer on shank: burn shank to twist, then align hammer to hit the strings the same as it did.

Loose hammerhead (don't know how to do this easily). (Maybe start loose, then CA?)

Centerpinning - loose versus firm versus approaching too tight. (Stanwood special adjustable flanges)

Different filing profiles: "egg-shaped" versus "following the grain" (Yes. And try some different hammers)

Filed with different grits of paper: 100, 220, 400, 600, 1000. (Hmmmm. And peek through the microscope too)

Ironing. (Ditto)

Raw hammers of a few types, starting raw, then changed by shoulder needling only, by shallow crown needling only, by different patterns and numbers of needle strokes, lots of possibilities. (Good)

All of these with a range of different blows, from pp to FF. Also at a variety of points in the scale.



These folks are also very grateful for our help, and the microscope studies are also a go. Apparently that's no big deal, but this anechoic chamber stuff is. They are creating "acoustic maps" of many instruments in a way that has never been done. 3D stuff or some new thing. I'll find out more as I go.

            On this particular subject, the book "Acoustics and the performance of music : manual for acousticians, audio engineers, musicians, architects and musical instruments makers" by Jurgen Meyer has a lot of stuff about 3D modeling of instruments, so your people might want to look at that. This was recent research done in German universities and conservatories, with recording or sound amplification applications as one of its focal points. (I'm on it! Thanks!)
Regards,
Fred Sturm
fssturm at unm.edu<mailto:fssturm at unm.edu>
http://www.youtube.com/fredsturm

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