Hello, I noticed that my “FDBK” button between 9 and 10 triggers a cracking sound on my sub 37 during a key press despite the other BUTTONS Panel “mixer” off. Does everyone have the same problem?
to see video !
http://youtu.be/w0n71JbNQzc
Hi toto587,
What you’re basically telling the synth is: I don’t want anything at all to make a sound, but then I want to take that nothingness and feed it back into itself infinitely. And then I want the end result of that to be perfectly silent.
I also get that sound in that particular setting (and strongly suspect that everyone else does too).
But I have to ask: What sound are you going for by turning everything off and then dialing in an extreme amount of feedback?
Thank you DemonDan for your reply!
Sorry if I do not speak very well English… 
The strange sound is a little less noticeable with the other 2 oscillators but causes instability and cracking sound. It is not pleasant to listen. I just need to not exceed 9 with the feedback on.
I still think back to the store this weekend for an aftertouch worries but I would not speak of “FDBK” button if it applies to all sub 37.
Otherwise it is a superb machine.
best regards
Problem? On an analog synth, I would call that a feature! 
This is actually pretty cool. With only feedback turned on you can get some interesting sounds if you have the mix level up in the 8 - 10 range. Turn on the arp and get some other modulations going for more fun. Also play with the filter cutoff and resonance. Who knew that nothing could sound so cool.
You convinced me, the effect is rather surprising with arpeggios… 
This Feedback (FDBK) parameter was added specifically to add chaos and instability to the audio circuit. You’re basically, on purpose, causing a feedback loop that would normally be avoided by anyone designing a circuit whose goal was to make perfect and predictable audio.
And, since the amount of Feedback needed to create the desired amount of chaos and instability changes based on what signals are feeding it and what is happening to the signal after it (Filtering, Resonance, and MultiDrive), the range of Feedback can go from none to extreme.
Reducing the extreme amount would certainly disappoint those who have found cool sonic results there. Especially if the extreme range was reduced just so that it wouldn’t make an odd sound when everything else was turned off.
Ok!
I can now see this as an additional feature.
Thank you
Just for the record I get the instability too but as others have already said you are creating a feedback by dialling the control right up that can go a bit ‘critical’ on the slightest impulse… mostly a series of clicking after a key press
Z.
And don´t forget: The filter can react as a soundsource in an analog synthesizer. If you turn on the resonance-knob to high values the filter itself begins to oscillate what ends in producing a sinewave, which frequency is controlled by the cutoff-parameter. The resonance is nearly the same as the feedback function. It´s a feedbackloop inside the filter-circuit. 
Best regards
Heiko