Stereo Mix question

I’ve been getting a strange unwanted effect with the stereo mix. I’ll try and explain it as best I can but apologies if I get a few terms wrong/mixed up. I’m no sound engineer.

So I have two tracks, track A and track B. Track A has a stereo mix that confines everything to the centre channel. Track B has a stereo mix that spreads everything out to the sides. Each track sounds fine when played on it’s own, but when I have both tracks playing at the same time, track B seems to be much louder in my right speaker, rather than being equal volume on both sides. What’s happening here?

Sounds like some sort of phase-cancellation issue going on.

Could you upload a small example song that clearly demonstrates the problem?

You should be careful when using the track Width setting, or the Stereo Expander device. They both create a type of fake stereo width effect by shifting the phase of one channel, until eventually at maximum width the left and right channels are 180 degrees out of phase. In some cases, a low amount of extra width can make a sound more interesting, or make it ‘pop’ a bit more in the mix, but in other cases you might actually suffer from phase cancellation problems.

Will be easy to tell what’s going on if you can provide an example song anyway.

Here you go. The sample in question is those really hard amen kicks. You’ll hear what I mean in the third part. It does seem like some sort of phasing thing, especially since you said that the stereo mix creates a fake sort of effect. I thought it literally just panned things out to either side, the same way the panning slider moves the sound to the left or right channel. I guess I just don’t know enough about sounds interacting with each other this way.

http://soundcloud.com/kantelian/ignore-this

I should have said an .XRNS example, so that I could inspect the precise settings you’ve used. No worries anyway, because it’s very obvious from your audio demo here. The second section (ie. “wide”) very clearly has the full stereo width expansion applied to it.

As I mentioned earlier, when you have the width cranked up to max like this, the left/right channels are 180 degrees apart from each other in phase. In other words, the right channel is almost a perfect mirror image of the left channel, as you can see from my screenshot below: (Zoomed in part of your “wide” section in the audio demo)

3783 renoise-width-inverted-phase.png

While this phenomenon sounds interesting over speakers, you never want this to happen in your mixes. If you mix this to mono, the channels will cancel each other out and result in almost total silence. You definitely don’t want this happening in a club or something like that, where big sound systems are sometimes configured to pipe mono audio through all speakers.

Essentially, what’s happening during your 3rd section, is that this heavily phase inverted signal is mixing back into the original sounds and phase cancelling out, creating the illusion that one channel is quieter/louder in the final mix.

My personal advice is to simply avoid the stereo width stuff, or only apply it in small, careful doses to certain sounds. Definitely avoid using it heavily on any critical elements like your main drums, bassline, etc.

Oh god. I’ve done this on so many other songs too. At least I’m learning from my mistakes. Thanks for the awesome response though!

So how do artists get things sounding “wide” then? For example, at 1:25 in this track http://youtu.be/2bJcppZt8mU the bass is pushed out to the “sides” of the mix while the drums are centre, and it makes everything sound less cramped. It’s like each channel has its own room to breathe in and everything isn’t bottlenecked.

This is probably turning into a lesson on production more than a Renoise tech question, so feel free to tell me to shut up.

I’ve have read Kurtz advise in some mixing topic that mixing in Mono is the first thing to do. It seems that you need it to prevent disasters from happening.

aehm… is there a mono button? I simply don’t find it. I could use a vst of course, but i guess renoise has one. I would love to have one especially on the master track as i mix / master on headphones.

You can use the native “Stereo Expander” dsp.

For mid side level checking, I currently use Voxengo’s MSED.

ok, so there is no button. Expander will work fine, thank you! :)

The width parameter has the same effect as the Expander’s Surround slider. If you look at the Master Scopes section up top, and just hold a repeated sine wave, you can see easily what the expander does. You can immediately see that the left channel at first (Surround between 0 and 50) will fade, then it will come back inverted.

@dblue: In the case of a sinewave I can agree that inversion and phase shifting of 180° is the same, but with the kickdrum sample I would definitely call that example inversion, not phase shifting.