[Dixielandjazz] Re: Cryogenic treatment for brass

[Robert Smith]

Mike,
I also play trombone and, as you say, the instrument sounds sweeter as the 
years roll by. Also, the plastic treble recorder that used to 'screech' 
sounds more mellow. I've also noticed that the 18kHz 'squeal' that I used to 
hear from desktop screens has also vanished, so in my case I think the 
mellowing is due to attenuation of the high register in my hearing.
I don't really know what effect residual stresses have on the timbre of 
brass instruments, but somehow I can't equate residual stresses to any 
effect on the note produced by the instrument. If there is any effect, then 
I would think that it would be confined to one or two notes only. After all, 
the note is produced by the column of air vibrating inside the instrument, 
so the instrument only has to provide a case for the air column, and act as 
a 'projector' for the note. I would think that keeping the inside of the 
instrument clean would have the greatest effect on the quality of the tone.
Here in Norway an instrument for calling farm animals resembling a straight 
bugle is made by wrapping layers of bark into the bugle shape. A 
trumpet-like mouthpiece is made of wood. The tone produced, although 
sounding somewhat melancholy, can be heard a long way away.

Cheers

Bob Smith