Muff's Modules & More

tonnu

i just got my fmvdo
the sound is excellent! im really excited

however im getting a really strange behavior when the QUANT is switched on

when the QUANT is switched on even with NO input at the 1v/oct and NO modulation of any parameters, my pitch randomly changes (not by a lot mostly by only a semitone--and it's an equal shift, not just for single notes)

is this how it is supposed to behave? what is the QUANT supposed to do?

due to lack of documentation, i guessed the QUANT is aimed at keeping the pitch at a quantized scale (i assume scaled to normal semitones?) even when you fm it to dath

so .. what's happening here? thanks!

Clockgate · Posted: Fri Apr 27, 2012 4:52 pm Post subject:

My FMVDO is totally stable with and without anything plugged in. It might be a power issue if you are getting near the current limit of your psu. Try unplugging a few other modules and see if it still happens.

BananaPlug · Posted: Fri Apr 27, 2012 4:54 pm Post subject:

That doesn't sound typical. Do you have a noisy freq pot?

Arcade Sinusoid · Posted: Sat Apr 28, 2012 12:29 pm Post subject:

You know i noticed mine doing this a couple days ago. Usually when i sequence it with rene i will shut the quantizer off. But when i sequence it from pressure points i will throw the quantizer on. When i was using the pressure points with the quantizer on i was hearing the pitch change slightly without changing the knobs on pressure points also. It didnt sound bad. Im thinking its something to do with the quantizer. I will try to drone it tonight with it on and see what happens.

visible cow · Posted: Sat Apr 28, 2012 1:41 pm Post subject:

I haven't quite figured out the quantizer on my fmvdo. I've noticed strange pitch variations when controlling it via keyboard but have chalked it up to my midi/cv converter not being correctly calibrated.

Arcade Sinusoid · Posted: Sat Apr 28, 2012 3:46 pm Post subject:

A quantizer just locks a voltage into a scale so if you were using a midi keyboard you would turn it off. You would use it for something like a sequencer that doesn't get locked to a scale such as pressure points. It basically just makes tuneing easier. Or its great for a random source CV like wogglebug or noisering.

ignatius · Posted: Sat Apr 28, 2012 4:45 pm Post subject:

Arcade Sinusoid · Posted: Sat Apr 28, 2012 6:01 pm Post subject:

I just got home plugged in and yes without anything plugged in its very stable. I did have this happen to another osc of mine it ended up being a broken pot. Good luck.

tonnu · Posted: Sun Apr 29, 2012 3:06 am Post subject:

i emailed bruce and he replied in less than a day, GREAT SERVICE!

so i think the first thing i misunderstood is that somehow i thought the quantizer will affect the FM'ed timbres, but no, it's just a simple quantizer

so if you get the same symptoms as me, here are possible cures:

- tap the course knob a bit as maybe the knob is "in between" notes
- if you are already using quantized CV's, then no need to turn quantize on
- may be due to power supply, but i don't feel that's the case for me

so all in all, A FUCKING AWESOME MODULE

i'll be looking at the dual wave soon

synthmaker · Posted: Sun Apr 29, 2012 4:38 am Post subject:

Regarding the quantizer on the FMVDO. Like most voltage quantizers
if the voltage is right on the threshold between two possible notes it can sometimes vary between the two possible quantized pitches especially if driven with an analog sequencer. This can happen because the A to D converter has finite resolution and a few mV variation between sequencer passes can be enough to toggle it either way if right on the boundary.
It works best with quantize switched off if the 1V/OCT is a stepped
voltage. Playing it from a keyboard with MCV would have the same issue. The Quantize function really works best when feeding it a continuous non-stepped voltage like from an LFO or Joystick etc.
It is still possible to use with a step sequencer but if you are getting variations on some notes just nudge the sequence step voltage so that it is off the boundary to get a more solid sample for the quantizer to work with.
Older style pre-micro quantizers used to wobble rapidly at the boundary which sounded like modulation. Now we add hysteresis to prevent this but the result is you can experience a bit of semitone variation.

Thanks
Bruce

Arcade Sinusoid · Posted: Sun Apr 29, 2012 10:29 am Post subject:

I actually enjoy the bit of randomness i get using a stepped analog sequencer applause

to me its an added bonus! Outstanding module Bruce! My 9u is jammed, but a new case is in the works. I'm planning on the whole modcan euro line to be living in the new case we're not worthy

visible cow · Posted: Sun Apr 29, 2012 10:41 am Post subject:

Thanks for the info!