Re: Mixing it...


Subject: Re: Mixing it...
From: Bob Pritchard (bob@interchange.ubc.ca)
Date: Mon May 24 1999 - 21:03:26 EDT


This reminds me of when a trumpet player was practicing in the underground
garage below the UBC school of music. He was playing long tones to warm
up. As I drove away from him I was heading for a flat cement wall. I heard
two pitches diverge, as the direct pitch shifted down, and the reflected
pitch shifted up, both caused by my motion.

On Mon, 24 May 1999, Charlie Richmond wrote:

> On Mon, 24 May 1999, KEVIN AUSTIN wrote:
>
> > About 6 minutes before the train arrived, we heard the first, very distant
> > whistle, followed by, what appeared to be a very faint echo. It appeared
> > to be continuously descending in pitch. Shortly after (since the train was
>
> This would be a result of the train slowing down.... Doppler says that
> the pitch will be higher than normal as objects approach each other and
> lower as they separate.
>
> > approaching), the horn sounded again, this time with a longer echo, and a
> > very clear echo, with the pitch slowly descending. A third time, the horn
> > sounded, closer yet, the echo lasted more than ten seconds, with a
> > descending pitch shift throughout.
>
> All of this is consistent with the train slowing down - the pitch would
> gradually reduce from the higher pitch resulting from the train moving at
> a high speed toward you down to the normal pitch as it stopped.
>
> > About 1 minute after the train left the station, the horn blew again --
> > with echo. This time, the glissando on the horn was ascending.
>
> Yep.... as the train left the station, it increased in speed and the pitch
> rose again from normal toward the higher pitch resulting from two object
> moving toward each other...
>
> > It took a couple of days to think this one out. It was ... but that would
> > be giving it away ... any solutions?
>
> Sounds normal to me as long as the train was always moving toward you....
> If it was moving away during any of this, you've got a problem.... ;-)
>
> Charlie
>
> +-------- http://www.theatre-sound.com/tsindex.html ---------+
> "Lo, thus, by day my limbs, by night my mind
> For thee, and for myself, no quiet find." - Sonnet XXVII
>
>

dr.bob pritchard bob@interchange.ubc.ca
School of Music, University of British Columbia
Vancouver, B.C. Canada V6T 1Z2
Vox (604) 822-3113 Fax (604) 822-4884



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