> I have one Z3000 and it's not quite as helpful as I had hoped. It's nice for quickly tuning your VCOs together (like adjusting all to A440) but no good if you want to calibrate anything, or to adjust to intervals as those would not be whole numbers. For that, you need something with hundredths or thousandths places.

Are we talking about measuring Hertz As no more than about +/- 5 cent accuracy is likely to be perceptible, unless it's in the form of how the different pitches interact with one another, as in the beating. See https://en.wikipedia.org/wiki/Cent_(music)#Human_perception for details. So hundredths are definitely going to be sufficient, with thousandths not necessary.

Just in case anyone's thinking of making such a thing, and doesn't want to make it more accurate than necessary. :)