Zipper noise when adjusting loop volume

[kulturhaus]

It seems that there is no volume smoothing in looper tracks. This results in digital zipper noise when adjusting the volume quickly, especially when low-frequency content is playing. It would be great if this could be fixed.

[kulturhaus]

Still there. Could this be fixed?

[syah71]

I cannot hear anything, not even when quick and rough ‘transforming’ the volume, even with bassline loops. It is as smooth as butter.

Could this be a hardware issue?

[kulturhaus]

I don’t think so. Here’s a video demonstration of the issue.

First, the audio is played in the looper, then as a sample (volume adjusted via sample level and via mixer), then in the looper again.

I chose a pretty low bass sound where the effect is the most audible.

S2400 Looper Zippering

[syah71]

That’s very loud!! I was testing my ears for a much softer sound. And it also makes the same static noise when you press start/stop.

I guess you are right about the faders having no hardware problem. Weird that it affects the looper and not the sampler. Isn’t this a grounding issue? Maybe these tips can help?

Make sure that all your device are connected to one wall outlet. Make sure that you make one serial chain of power strips. Any parallel chain will cause trouble, whether it is using multiple outlets, or by splitting the chain into more parallel chains.

[tnkz76]

I can reproduce the issue here when sampling a clean part of your Youtube video in the looper.
Same “sound effect” when moving the fader quickly.

I can reproduce clicks and zipping sound as well when sampling a clean looping subwoofer from the computer via USB in the looper.

[kulturhaus]

It’s not static. These noises are digital artifacts. The problem is that the volume is adjusted in rather big steps (it has to do with the UI update frequency). When these steps are not interpolated with respect to the sampling frequency, these kind of noise occur. Especially when using very low sounds (I assume, with frequency less than the UI update frequency?).

Now with the normal sample playback, there is such smoothing implemented (you can still hear the noises but they sound filtered, much less pronounced). But for some reason the smoothing is missing in the looper. @av500 may tell us why:)

[syah71]

What about the DC offset then?

[kulturhaus]

What about it?

[panelist]

I can also replicate the zipper noise issue

[avery.moss.magic]

I can also recreate this noise - I am aware that digital stepping is a thing, but most synths that utilize digital control (like the master volume on the UDO Super 6) use smoothing to avoid this.

[kulturhaus]

It’s quite remarkable that these bugs are still around after 3.5 years!