Relationship of terms, was Important Question, was lucky break

Alan R. Barnard mathstar@salemnet.com
Wed, 18 Sep 2002 22:37:41 -0500


Aha, aha, aHA! That's where I'm going with this ... how do Hz, Cents, and
Beat Rates all interplay?

Does a certain percentage (cents) of distance between two tones determine
the beat rate without regard to the Hz of those tones, or does it change
with scale location, i.e., frequency?

Unisons: Small changes in the treble area make a very fast beat because the
frequency changes drastically, compared to strings in the bass BUT what we
call "cents" is obviously proportional and/or exponential to frequency
because any given difference in cents means much a higher difference in
frequency (Hz) in the treble than in the bass.

Anyone have an oscilloscope?

Experiment: One string of a bichord base note at, say, 110 Hz Fundamental (a
theoretically perfect A3) and its companion string at 111.1 Hz. This is a
one percent difference. Is that one "cent?" What is the beat/roll rate?

Now compare that to two strings in the treble, one at 2093.004
(theoretically perfect C7) and another in that unison at exactly 2113.934
Hz--also a one percent difference.

Will those two misaligned unisons each beat at the same rate exactly? Does
each pair differ by the same "cents" if they differ by exactly the same
percentage of Hz?

Is my brain just spinning cobwebs, or does anyone else wish they had a
clearer understanding of the relationships of these terms?

Alan R. Barnard
Unraveling in Salem, MO

----- Original Message -----
From: "sid blum" <sid@sover.net>
To: "Pianotech" <pianotech@ptg.org>
Sent: Wednesday, September 18, 2002 8:59 PM
Subject: Re: Important Question, was lucky break


>
> ----- Original Message -----
> From: Kevin E. Ramsey
>
>   "  Well, Alan, unless I'm wrong (In which case I'm sure I'll hear about
> it), in the area of the upper temperament, the difference between A440 and
> A441 is approxiamately 4 cents, so 442 would be eight cents sharp.
>     That being said, one cycle at A0 would be about 64 cents at the
> fundemental level, according to Jim Coleman Sr. So I suppose that one
cycle
> per second at the top of the piano would probably be a fraction of a cent.
> Just this month he mentioned that, and remarked that it gave a whole new
> light on lower bass tuning, and quibbling over a few tenths of a cent. "
> ********************************************************
>
> This reminds me of a thought I had recently while reading various posts
> relating to ETD s.  Would it not be useful to have an ETD that could also
> read out in the language of frequency (cycles per second)?
>
> I'm way over my head here, but I'm thinking a device such as this could
> relate to beat rates.
>
> sb
>
> _______________________________________________
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