Sub Oscillator Problem

[zoso335]

Hey so I just bought a Rev2 and noticed an interesting issue. I made an init patch and had both oscillators up with the sub oscillator all the way up. That all sounded normal. I put chorus on and noticed that sometimes the sub would cut out so I played one note repeatedly and the sub would cut out randomly. I thought this might just have to do with the chorus effect so I took it off and it still continued! Sometimes even while holding a note it would cut in and out. Any idea why this could happen?

[Quatschmacher]

Could it just be phasing of the oscillators? Or the sub oscillator is defective on one voice card?

[zoso335]

After some more tests I discovered the following:

On an init patch with both oscillator 1 and the sub turned all the way up everything sounds fine. When I turn on osc slop is where I start noticing the sub not being present on some notes. I understand that there would be some phase cancellations but it doesn't make sense that the fundamental frequency of the sub would cancel out because it's an octave below oscillator 1.

To provide more detail, the sub isn't present on around 4/16 repeated notes, and there isn't a pattern to indicate it's specific to certain voices.

[AlainHubert]

I've just tested this on my 16 voice REV2, and the sub is present on all voice, no matter how much Osc Slop I set.
I think you might have defective sub-oscillators perhaps ? Have you contacted Sequential Support about it ?

EDIT: when doing your tests, press the Global page to see which voice is assigned/playing and maybe notice which ones don't have the subosc sounding ?

[zoso335]

I've just tested this on my 16 voice REV2, and the sub is present on all voice, no matter how much Osc Slop I set.
I think you might have defective sub-oscillators perhaps ? Have you contacted Sequential Support about it ?

EDIT: when doing your tests, press the Global page to see which voice is assigned/playing and maybe notice which ones don't have the subosc sounding ?

After another test I realized my problem only happens when hard sync is on. Is that normal? I would think since the sub is an octave below there still wouldn't be phase cancellation on the sub's fundamental frequency.

[AlainHubert]

I've checked this with the Sync on and, yes, some of the sub oscillators are near silent because of that. Especially noticeable if Oc1 Fine Tune is raised above zero, with Osc1 and Osc 2 set at the same frequency (C2 for example). That's normal.

If you want to hear the sub oscillator do something really weird, try setting Osc1 frequency to C6, and sweep the Osc2 frequency across the whole range from C0 to C10 and listen to the effect on the sub-Oscillator !

[littletinymonkey]

I spent several days in May of 2019 working to demonstrate this issue with support. Eventually I noticed that I can turn OSC SLOP up and back down, sometimes slow, sometimes fast, and depending upon the current state of whether or not the SUB OCT is currently working/audible/present, turning OSC SLOP sort of "enables and disables" the SUB OCT at random. Of course we tried all sorts of troubleshooting steps to rule out all sorts of things. Ultimately I ended up sharing a sysex file with support and received this reply:

I was able to recreate the issue here as well. It doesn't seem to matter whether it is set to wave reset either since I was thinking it was the culprit (waves triggering at different points and which might cause a phase issue with the sub oscillator). I'll have to investigate this more since we don't have a lot of people mentioning this and I can only deduce that it has to do with the number of voices playing and just being slightly off timing enough since there is no replicable way to do this. For now I'll put it on the bug list.

I'd probably be a happy Rev2 owner if it weren't for this bug. I'm sad that it hasn't been addressed yet.