How Stereo Expander Works?

Could someone explain how exactly Renoise native Stereo Expander works?

It is probably not just shifting phase of channels, since I can still hear the signal in mono? Is it tweaking EQ, delay etc. separately in channels to avoid phase cancellation?

I’ve tried several stereo widening techniques and I’ve found that Renoise default expander sounds pretty damn good and mono compatible. But I want to be sure if my mono button VST is working correctly. Can you get phase cancelled signal with Stereo Expander somehow?

Well, it is perhaps the signal shifted mixed with the original mono signal.
Try the Render Selection to Sample option and compare the visual representation of both the original and the rendered selection :)

Thanks! If I get this right, it seems that both channels have been shifted, but mixed slightly differently.

Also noticed now that Surround setting creates phase cancellation. Previously I had stereo reverb in my chain that was nicely cancelling that cancellation :)

Anyway, basic expander works just perfectly for me. Better than Haas, pitch-shifting or chorus.

Clone your signal on a second and third track. Leave the first and third track untouched. On the second track add a gainer and set it to phase inverse. Also add a stereo-expander to that track and set it to mono. Send track 1 and 2 to one Send-channel (mute after the Send-device). The resulting signal of track 1 + 2 on the Send-channel should be the pure stereo signal. Now add a Gainer on the Send-channel and set it to phase inverse again. This should eliminate the stereo-signal in the summary of the Send-channel and the third track. The result on the master track should be the pure (stereo phase canceled) mono signal now.

Haven’t tried this, but should work in theory.

Right. The Stereo-Expander by design can’t make a mono signal become stereo. At least as long, as not using the surround setting of course. So it’s actually impossible do add phase cancelation with the native Stereo-Expander.

Edit: Just to make this clear and avoid misunderstandings. Using the surround feature, you def will create phase cancelation. That simply is the way surround sound works.

100% surround in stereo = 100% phase cancelation in mono

Yes, stereo expander does not seem to “work” with mono wav. My guitar samples are stereo, but left and right are identical (so it is kind of mono really). When I use stereo expander in this sample, it clarifies the mix, leaving more space for lead instrument in center. At least that’s what my ears are telling me. I’ve tried other widening tricks too, but I am quite happy with the default expander (and it’s damn simple just to drop it in track).

So if it sounds ok, it is ok? :)

As long as it still sounds OK when doing a mono compatibility check then I would say yes :)

hello, it’s possible to make signal panned hard left & right with nothing in the center, without 3rd party plugins? if possible - how? thanks

hello, it’s possible to make signal panned hard left & right with nothing in the center, without 3rd party plugins? if possible - how? thanks

Of course it is. Use old school record 4 times. Then hard pan them.

record what?

Sorry my shit opinion, but my crappy usual ‘workflow’ is to just record your thick hook junk (guitar or synth riff) 2 or 4 times and pan them hard. Just a thought. Works better than the plugs, I think, but do what ya must!

i asked how to make signal to be at SAME time at hard left & right and ‘hole’ in the center. if panned hard left in one track and hard right in other, it is in center. thanks

Well, my reply is rather late, but… if you record different performances (or even somewhat different vst settings) then pan them hard left and right, you will get that ‘hole in the center’ sound.

Very old technique by now. Often better than effects, IMO.