Posted by Rick Denney on March 08, 2004 at 11:33:30:
In Reply to: Mouthpieces and intonation? posted by Mr Cole on March 07, 2004 at 20:28:31:
After Art's post, nobody will want to claim expertise. Certainly not me!
The notion is that a mouthpiece with a smaller volume will have a generally higher peak in its impedance curve, as will a mouthpiece with a larger throat. The larger throat will also broaden that impedence curve.
But the impedance of the mouthpiece is just one influence on intonation. The impedance of the instrument and the impedance of the lips also control pitch. Sometimes, the latter two are so strong that no mouthpiece choice can make a difference. The resonance peaks of the instrument are sharp, while broad for a mouthpiece, so the best one can expect is for the mouthpiece to have a subtle influence on the instrument. And some instruments are more open to those influences than others.
On the other hand, I know that when I use a Conn Helleberg or deeper mouthpiece on my Yamaha 621 F tuba, the intonation goes wacky. I know that my Besson euphonium plays uncontrollably flat using any bass trombone mouthpiece, but is much more in tune using a Denis Wick/Steven Mead euphonium mouthpiece. My B&S F tuba is much easier to tune using the smaller Finn MF-4 (or a PT-64) than with a deeper contrabass mouthpiece. But I can't change the intonation tendencies of my Miraphone 186 with a different mouthpiece, and it plays pretty well in tune no matter what I stick in it.
And there are anecdotes from players at the top of the biz. Jay Bertolet talks about how the Laskey 30H solved some troublesome intonation problems on his Nirschl, for example.
In most of these cases, there seems to be some quirk in the impedance of the instrument that is counteracted by a quirk in the impedance of the mouthpiece. Instruments without those quirks seem to be less sensitive to mouthpiece choice, perhaps.
Rick "whose intonation is barely good enough to support any opinion" Denney