Posted by Rick Denney on August 28, 2002 at 15:38:19:
In Reply to: Re: Re: Re: Re: Re: Re: conductor foibles - tuning posted by GC on August 28, 2002 at 15:25:53:
Also, a tuba with wide dispersion and a relatively weak central path introduces multipath distortions, where sound waves bouncing from walls mix with sound waves coming directly from the instrument. The sine wave (which is nothing at all like a tuba sound and we are glad of that) is shifted in time for those paths that are longer, and those shifts can have big impacts on the relative strength of those upper harmonics. Tubas with more directional projection display this effect to a lesser extent, but it is true to some degree for all tubas, it seems to me. And the more live the room, the more true it is.
Furthermore, the tuning of harmonics can cause the interpreted pitch to change as a result of those harmonics being stronger or weaker in the mix. So, the frequency doesn't change, but the perceived pitch does, because of room-induced changes in tone color. The bigger, deeper tubas (NOT darker) with complex upper harmonics that reinforce the depth by establishing a collection of difference tones at the fundamental don't necessarily do it precisely. If you hear difference tones in the sound that vary over a small range, the pitch of the tone will be hard to perceive. Dark instruments (my definition--those that more predominantly produce the lowest overtones) have less of this effect.
It is much easier for me to tune my Miraphone outdoors than my York Master in a live hall.
Rick "who can't get Korg to agree with his pitch sense" Denney