[sdiy] frequency counter

[WeAreAs1 at aol.com]

In a message dated 6/25/04 6:49:01 PM, mark-romberg at utulsa.edu writes:

<< anyone know of a simple-ish frequency counter circuit?  beginning to 
realize im going to need one to tune oscillators and things in the 
analog world as i dont have perfect pitch :/ >>

Mark,

For tuning VCO's, a guitar tuner is much more useful than a frequency 
counter.  I prefer tuners that have an analog (VU meter) readout, such as the BOSS 
TU-12H.  You can easily pick one up for about $40 to $50 on Ebay.  A mechanical 
strobe tuner is good, too, but kind of overkill for the app.  I've been 
working professionally on synths for over 25 years; my standards for musical 
perfection are very high, and I would NEVER tune a VCO with a frequency counter.  It 
just doesn't work.  I'm sure others might argue otherwise.  Let them.

Michael Bacich

BTW - the preferred method for tuning a multi-oscillator synth is to tune 
just ONE oscillator using the tuner.  Get the scaling, octaves, hi-frequency 
tracking, and offset as close as you can (according to the tuner), then tune all 
of the other oscillators to that first oscillator.  If you use the tuner on all 
your VCO's, it may get close, but it will never be perfect (if you use a 
frequency counter - good luck!).  This applies especially to monophonic synths 
such as the Minimoog.  On polyphonic synths (the few that have user-tunable VCO's 
and no auto-scaling [not the same thing as auto-tuning!], such as the OBx, 
OBxa, Jupiter 8, and Jupiter 4), it's OK to tune the first VCO of each voice to 
the tuner, but be sure to then tune the second VCO of each voice to the first 
VCO of the same voice.  (the rules are different for synths that have 
auto-scaling, such as the Prophet 5, Jupiter 6, OB8, etc. - most of those synths 
require very little in the way of calibration)