William B wondered My questions come in here. I've become reasonably convinced that 'pop tone' is an important consideration in the performance of any given mouthpiece design. What is 'proper' pop tone? What influence does mass of the mouthpiece have on the effect of pop tone? What factor does annealing play in the role of pop tone effect? *********** By pop tone, I assume you mean the sound you hear when (for example) you hit the rim of the mouthpiece against the palm of your hand. When the mouthpiece volume is larger, the pop tone is lower in frequency. The most important effect of the cup of the mouthpiece is to amplify harmonics near the popping frequency. If the popping frequency is high, the mouthpiece will result in a brighter sound than if the popping frequency is low. Another effect is that a high popping frequency makes it a little easier to hit high notes. Yet another effect is that the acoustical length of a mouthpiece, which differs from its actual length, is affected by mouthpiece volume. So you may need to retune your horn when you switch from a shallow to a deep mouthpiece, even when they have the same actual length.
The pop tone that is "proper" depends on what results you want. I would guess that the mass and the annealing of the mouthpiece are far less important than the volume. Most mouthpieces are pretty thick (compared to the bell and much of the cylindrical tubing of the horn) and small in diameter; this makes it difficult for the walls of the mp to vibrate very much. It is true that the pressure variations in the sound going through the narrowest part of the mp are greater than in any other part of the horn. Even so, I remain dubious that the effect would be very significant. I am unaware of any scientific studies that have been made on this, however. I think it is likely that a player would sense that one mp vibrates more than another; but this does not necessarily translate into a different in playing quality, IMO. Bill also wrote At a temperature, just short of the softening point, the atomic structure can move just enough that all the stresses are equalized. During a slow, uniform, drop in temperature, the crystal structure remains homogeneous, and at room temperature would be considered 'dead soft annealed'. Some times this process is repeated, but this time the metal is cooled very quickly once it reaches a predetermined temperature. This locks the entire crystal structure into the characteristic form for that temperature, and sets the metal to a 'harder' 'temper', that generally favors higher frequency vibrations. ************ You might want to took at a book about copper and its alloys to learn more about the effects of heating and cooling the metal. Steel can be hardened by tempering; but brass does not show this effect. If you took some "soft annealed" brass and raised it to some temperature below the annealing temperature, you would detect no change in the softness of the metal. You stiffen brass by work-hardening. This may be why so many local thugs carry around horn mouthpieces instead of brass knuckles. Gotta go, Cabbage _______________________________________________ post: [EMAIL PROTECTED] unsubscribe or set options at http://music.memphis.edu/mailman/options/horn/archive%40jab.org
