[music-dsp] RE: strobe tuners

Michael Gogins gogins at pipeline.com
Tue Nov 11 16:21:00 EST 2003


Your recollection is more precise than mine, and helps me remember the
lovely thing better.

============================================
Michael Gogins
gogins at pipeline period com
Irreducible Productions
CsoundVST, an extended version of Csound for programming music and sound
Available at http://sourceforge.net/projects/csound/
============================================


----- Original Message ----- 
From: "James Chandler Jr" <jchandjr at bellsouth.net>
To: <music-dsp at shoko.calarts.edu>
Sent: Tuesday, November 11, 2003 3:46 PM
Subject: Re: [music-dsp] RE: strobe tuners


> ----- Original Message ----- 
> From: <gogins at pipeline.com>
>
>
> > The strobe tuner I remember from high school had a wheel with the
> > fundamental plus a number of harmonics on it. The fundamental was on the
> > outside, and the harmonics were on inner rings.
>
> Yes, the harmonics printed on the wheel are in octave increments.
>
> IIRC, most strobes put the low octaves on the inside of the wheel, and
high
> octaves toward the outside, where there is more linear space to place the
tiny
> stripes. But there may have been strobes oriented the other way.
>
> Set the pitch knob to 'C', and the wheel spins at a rate so that any
sinewave
> 'C' in a wide audio range would brightly light up and "stop" one of the
printed
> octave bands. Some bands adjacent to the correct octave will light up
stopped,
> but 'fuzzier', since the strobe light is working against some 2^x ratio on
those
> adjacent stripes.
>
> If you play a 'F', 'G', 'E', or 'A' sine wave when the pitch knob is set
to 'C',
> it will give you a 'dim' moving pitch indication on some of the stripes,
because
> those notes are integer-related to the 'C'.
>
> When tuning a real-world instrument, the assortment of lit bands (and the
> direction of motion of each lit band) works out a rough visual average of
> whatever octave harmonics, and other low-order harmonics, happen to be in
the
> signal.
>
> The ear seems to determine pitch of a complex tone from the "general pitch
> clustering" of the louder harmonics. There has been some research claiming
that
> human pitch perception may be "wetware autocorrellation". So the strobe's
> "averaging out among harmonics" seems to indicate results which are pretty
close
> to what the ear expects to hear.
>
> There is a rarer, huge expensive 12 wheel variant of the Strobe Tuner,
models
> made by Conn, Peterson, and perhaps others. One wheel for each chromatic
note.
>
> James Chandler Jr.
>
>
> dupswapdrop -- the music-dsp mailing list and website:
> subscription info, FAQ, source code archive, list archive, book reviews,
dsp links
> http://shoko.calarts.edu/musicdsp
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