You really don't need a freq counter or strobe tuner or oscilloscope or DVM
to set tracking on these babies!
It's really easy to do by ear! These are the easiest VCOs to set tracking on
that I've ever seen. All you need is a second VCO, either MOTM or from any
other source, as long as it can just sit there and not drift.
1. Set up your reference oscillator to play a sawtooth at about 125 Hz (one
octave below middle C, exact pitch does not matter at all). It should not be
connected to any keyboard voltage or modulation, you just want a straight
steady tone. I find it easier to set the tone to play continuously, either
by turning up the initial VCA gain or, if it is an external VCO from some
other synth, prop the key down with something.
2. Hook your MOTM-300 to your midi/cv source, and use a sawtooth. You should
have already set the trimmer to approximately its center range as the VCO
instructions told you to. Make both oscillators the same loudness. Don't
play so loud that you cause other things in the room to rattle, etc. Play
one octave below middle C on the keyboard, and tune the MOTM exactly to the
same pitch as the other VCO using Coarse and Fine controls. When the pitch
is very close, you hear "beats" between the 2 pitches. When it is in tune,
you hear none.
3. When they are perfectly in tune, play a note one or two octaves higher
and you should hear that the VCO is either somewhat sharp or flat. Turn the
Fine tune up or down until it is in tune again. If you had to turn Fine
clockwise, it was flat, and you will need to turn the trimmer clockwise a
little bit. If you had to turn Fine CCW, it was sharp, and you have to turn
the trimmer CCW some.
4. Now play the low note again, and retune the MOTM so that it is perfectly
in tune (no beats), and repeat steps 3 and 4 to refine your tuning until you
zero it in.
5. You can continue to refine this by playing a wider interval. I generally
stop after about 4 octaves.
Repeat for all VCOs, setting up 1 as the drone and one for calibration.
Easy! It should not take you more than 5 to 10 minutes per VCO.
Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@... > about the 1V/OCT now i'm shure i need a frequency counter to do it the
> professionl way.
> can any body recomend on a low cost hi quality counter ?
>
> thanx
> Gur Milstein