Re: Amplitude and pitch of sound waves

[John Denker <jsd@MONMOUTH.COM>]

At 12:05 AM 11/29/99 -0500, Michael Edmiston wrote:

> This means that a stringed instrument with stiff wires under high
> tension

Ha!  A nit!  Pounce pounce stomp stomp :-)  ....  If stiffness is bad,
tension is good.  I would have said "wires with too much stiffness and/or
not enough tension".  Think about ye olde wave equation.....  Think about
ye loaded wires in the bass (providing more mass thereby allowing more
tension, with less-than-proportionately more stiffness).......

> has a harmonic series
> that is not perfect multiples of the fundamental.  The harmonic series
> goes sharp.

As normally tuned, they don't sound sharp.  We say they are stretched
(frequency-wise) but we don't normally say they are sharp.

> Not all instruments are like this (or at least not so severely so), and
> I do not think this is justification to redefine an octave.

There's an unshakeable consensus among musicians that the nominal octaves
on a piano are indeed octaves.  They aren't quite the same as the octaves
on, say, a bugle -- but the thirds and fifths aren't the same
either.  Life's tough all over.

>   I'll stick
> with the definition of an octave as a factor of two in frequency.

That's a physics nerd's definition, not a musician's definition.

BTW, Max Matthews and John Pierce cobbled up some instruments with
*extremely* nonstandard partials -- not even remotely related to anything
that ever came out of a cylindrical pipe, conical pipe, or string.  Perhaps
surprisingly, they sounded fine.  They sounded much less weird than a lot
of the stuff that passes for "modern music" these days.  Perhaps even more
surprisingly, our heroes were in some cases able to create scales and
chords, and even major-like and minor-like modes.  Lining up the partials
was IIRC a big part of making the chords work.

> Returning to the original statements that initiated this thread.  I
> would not say that pitch *is* frequency.

I'm not even sure the note played by a piano *has* a definite
frequency.  The waveform is not periodic, not even to a good approximation.

>   I would say pitch is *related to* frequency.

Agreed.

>   So I don't view the pitch statement on the poster as
> too much of a travesty.

Agreed.

>   But the amplitude statement is pretty bad.

Agreed.