The walls consist of half-circular columns, floor to ceiling. Compared
to other halls, the walls are hard and reflective. Sound is reflected in
many directions. The trained ear hears reverberation a quarter tone tone
low. I doubt it is a pschological phenomenon. (01)
-- Jeff (02)
> -----Original Message-----
> From: Randall R Schulz [mailto:rschulz@xxxxxxxxx]
> Sent: Thursday, September 06, 2007 3:51 PM
> To: [ontolog-forum]
> Subject: Re: [ontolog-forum] Current Semantic Web Layer pizza
> (was ckae)
> On Thursday 06 September 2007 13:30, Schiffel, Jeffrey A wrote:
> > ...
> > It is an example of inadequate design, and is quite easy to achieve.
> > Consider that the hall consists of an audience chamber and a stage
> > house. The chamber is quite high with reflective walls. Sound,
> > especially from high-pitched instruments, ascends into the
> upper stage
> > house and into the hall. In a hall 120 feet deep, sounds would only
> > need to be deflected a couple of feet (at 440Hz) when
> bouncing off the
> > walls to hear a doppler shift of a quarter tone.
> Something has to be in (relative) motion for the doppler
> effect to take place. Either the source, the receiver, an
> intermediate reflecting surface or the medium.
> Perhaps there's a coherent air-flow through the hall that
> causes a frequency shift? But that would be a linear
> (additive) shift and the concept of a "quarter tone" is
> multiplicative (we're all quite conditioned nowadays to hear
> in an equal-tempered scale where each halftone is a factor of
> the 12th root of two change in frequency).
> > > For example, suppose the incoming frequency f was X Hertz and the
> > > outgoing frequency was X-y Hertz. That would imply that y
> > > vibrations per second were somehow "lost"
> > > or, even worse, "stored" for future transmission.
> > >
> > > That is an extremely complicated nonlinear transformation.
> > > You could accomplish it by recording the sound and later
> playing it
> > > back with a slower turntable or the equivalent in
> electronics. But
> > > I don't believe a typical music hall could do that.
> > In fact, they do. So does "echo point" in the mountains, where the
> > sender often hears the reflected sound a bit lower.
> Perhaps in an open environment there are further dynamics
> (and certainly net, though non-uniform motion of the air
> would be the rule rather than the exception). Also, the
> atmosphere outdoors could be dispersive, for example.
> There's also the possibility of purely psycho-acoustic
> effects causing the impression of a pitch change.
> In any event, I am inclined to agree with John that a static
> such as a concert hall could not produce a frequency
> multiplying effect
> such as rendering all pitches a quarter tone flat.
> Another perspective on this (putative) phenomenon is that such a hall
> would have no resonances, since any sound would have a continually
> declining frequency. Sort of like the Bohr atom, now that I think of
> > Regards,
> > -- Jeff Schiffel
> Randall Schulz
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