Scratchy noises on audio while lowering volume caused by Octatrack AB fader

Hey guys, new Octatrack MK2 user here. I don’t know if I have fader A B issue or not. I’ve set A for Volume MIN, and B for MAX. When I slide fader to the left I hear some little scratchy noises on my audio, this only occurs with lower fequencies.

I attach the audio on which you can hear what I am writing about (only when turning down the volume with the fader).

Could you please tell me if this normal behavior, or maybe my unit is faulty? Or maybe I’ve missed something during configuration (at this moment I’m using thru machine).

Does it make the scratching sounds with other, non-volume related scene changes? For example, if your cross fader is set to filter cut-off, does it make the noise or is it only volume related?

You could run Test mode to check for potential hardware or software issues. Procedure is explained in the manual. Replacing the crossfader is easy, it’s a self contained unit in the Mk2s, so I wouldn‘t worry too much.

In the case of the filter, I can hear a similar issue, maybe a little quieter, but still noticeable. In addition, I noticed that when I quickly change the volume of thru machine, I hear something like resonance. Seems to be volume related only. When I change different values other than volume (maybe filtering as well), there is no issue.

There are no issues detected in test mode. The crossfader seems to be working properly. I’m wondering if it’s normal or not. Because if not, I will return the OT to the store or ask for a replacement for another unit.

I don‘t think that’s normal. You should be able to cut audio or fade in/out smoothely.

The recording you provided reminds me of faulty/scratchy potentiometers (I’ve never actually heard a faulty crossfader, but I guess it sounds like faulty pots/faders, so if you can return it and get a replacement, probably best to do that.

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The crossfader is optical and digital - there is no audio going through it - scratchiness wouldn’t be as a result of dodgy contacts in the fader like an old potentiometer.


Oh yeah, of course! No idea why I forgot that. Need more coffee…Went to bed at 9 am. :grin:

Nonetheless it‘s not normal. Maybe an issue with a ribbon cable not seated properly? Probaply still best to just get a replacement.

Thanks for your feedback guys. I think I will contact with store in this case.

Example how it sound with only one function applied to crossfader A scene - Level to MIN.

Example how it sound if I’m using potentiometer dedicated for Volume function in Thru machine. I’m changing value fast.

It doesn’t sound good. This is a new device, which even during testing in the new project sounds so weird. I’d like it to actually run smoothly, without scratching, and worsing audio, because that’s irritating. OT is not a cheap device.

Maybe later as a final step I will try restore the device to factory settings and upload the latest firmware again. But I think it will not help.

That sounds weird. Does this also happen with flex or static machines?

Try to lower the amp vol and thru volume so that you have a relatively quiet signal to rule out any clipping and test again with crossfader on xlvl.

Also try a fast lfo on amp volume and try crossfader on xvol (hold scene button, xvol appears on the amp page).

It’s been 10 year since I had an octatrack, but I would suggest that you check the values of other parameters such as the dist, SRR and the like. Whilst you are only changing the volume or level, you maybe firing off an effect with your volume changing


I’d use a looped sine waveform to check properly. 110 hz maybe.
I don’t think your unit is faulty.

I noticed this issue also on completely new project. I checked also with Recorded sample in Pickup machine, and also with neighbor machine and final result is still same.

Still don’t think you’ve got a dry signal.

It’s interacting with something.

I think.

Looped sine would be best, because you can easily make out additional harmonics. Have you done your tests without effects inserted in the fx slots? Master track?

It only happens with the crossfader, but not when turning the level knob - what do you think is causing this?

I can’t hear properly, smartphone only and I’m not with OT. I remember having artifacts with the crossfader.

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Yeah I’ve heard this on my OT mk1. I was fading in a track and there was this “digital artifacting” (for lack of a more precise term).

I concluded it was a feature, not a big, and didn’t really give it much thought. It would only happen in a live situation because for a recording in a DAW I would just use faders for this. So at the time, I didn’t do much to diagnose it and just leave it at that. I was a pretty unsophisticated OT user at the time.

Because of your post I just opened up the file and I see that I have two tracks that I’m using the xfade to bring up by using the Amp sections Vol paramter. Both are static machines. One is set to slice mode while one is just playing a loop. The slice mode is just some chords glitching around AND it has the Lo-Fi Effect applied.

The track with the Lo-Fi track definitely gets additional noise added to it even tho the cross fader only modifies the Vol parameter. I removed Lo Fi and it stopped immediately. Put LoFi back on and ran each parameter up and the BRR one does not respond well to the xfade moving the Vol.

Not sure if this is your root cause but it is mine. This particular file is about 5 years old and I hadn’t given it much thought until your post.


Again, thank you guys for your input. I have done various test (also tried to fade out volume with xvol option in AMP section), still this weird noise is noticeable. I’ve done these tests in completely new project, I’ve reset device to factory settings, and also uploaded again latest firmware. I’ve also put various signals sources to OT, and final result is still same.

From what I managed to specify, it’s probably not necessarily a crossfader-related problem, because FUNC + Level changes the value for MAIN and then I also hear these additional noises.

But ultimately, I will probably send this unit back to the store tomorrow and ask for a refund. I don’t think I want to test the second unit - I’m afraid that this issue is a ‘feature’ that from ever be in OT, just not everyone pays attention to such ‘small’ details. For me it’s just unacceptable, not for this money. Certainly in a normal situation I would not pay attention to it, I was just testing a crossfader with the simplest possible (as I thought) function. And because of that, I’ll probably always hear it.

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On the inputs where your thru machine is set do you have the noise gate set to -INF?

Yes, noise gate is set to -INF