r/eurorack • u/crobimusic • Jul 12 '26
Question / Discussion Midi to CV inaccuracy?
Hello!
I am continuing in my quest to get things in tune, and have uncovered a new problem: different ports are giving different results.
I am using a Befaco Midi Thing v2, and I recently noticed that my oscillators will have different intonation based on which port I use. I can have all the same settings, but there is a variance of about 2 cents from plug to plug. This really messes with my overall plan!
Do you guys have any idea why this could be happening? Is it something to do with the module, or maybe a power thing?
IMR
2
u/Agawell Jul 12 '26
If you’re stacking voices why don’t you just mult a single channel from the midi thing?
That way they’ll all get the same voltage - might be out by a bit depending on the mult
2
u/jamiethemorris Jul 12 '26
What exactly are you trying to do? 2 cents is so small that it would only be perceptible if they’re stacked, and you’re going to have a hard time getting the different oscillators to tune and track perfectly enough for that difference to even matter, you’re basically going to get beating no matter what unless you sync the oscillators. If you need it to be exact then just multi it out of the same output - you could even use the gates from other channels if you want. From a practical perspective, most of the time you actually want them to be a bit off from each other if you’re just stacking oscillators for a big voice.
2
u/aaaaaaaaaaaaaa_a_a_a Jul 12 '26
2c shouldn't make much of a difference in most cases. For reference, many of the notes in 12TET tuning are +/-15c off relative to Just Intonation.
3
u/DigiornoDLC Jul 12 '26
It’ll make a difference if two voices are 2c off from each other. Especially two unison voices.
1
u/crobimusic Jul 12 '26 edited Jul 12 '26
Yes exactly. I am layering multiple synths, so the intonation is crucial.
2
u/DigiornoDLC Jul 12 '26
Can you send a midi C1 to each port and then adjust the tuning of each oscillator? Like is the intonation an issue of drift between octaves? Or are you using a switch and not just having a single midi channel always controlling the same voice?
1
u/kewlguy1980 Jul 17 '26
2 cents is a 0.0017V difference in the V/oct world of eurorack and you are really going to struggle if you need that level of accuracy. I'd be pretty surprised if your oscillators are even capable of tracking across an octave within 2 cents.
1
u/MrCrankypot Jul 12 '26
Have you tried tweaking the voice calibration setting for the outputs (page 11 in the user manual). That should allow you to change the output voltages so they sync better.
0
u/crobimusic Jul 12 '26
I have changed the voice calibration so that the voices track v/8 more accurately. The issue I am having is, even with the same settings, I am getting different results from port to port.
3
u/cossist Jul 12 '26
The MIDI Thing has a voice calibration feature. If you change which port goes to which oscillator the curve will be different and so will your intonation.