bitflipper


Exactly. If, for example, the left and right signals are the same but phase-shifted, then they are part of the Side component. And they'll sound nasty when combined. They may sound great in headphones, but that comb filtering will be audible when listening to speakers off-axis, or in mono. 

No.

What I am saying is that some comb filtering that maybe apparent when the side component is heard in isolation may not be apparent when you are listening in stereo or true mono (both mid and side components included).  IOW listening to the side component alone can remove elements that CAN cause a comb filter effect.  I'm not saying that's true in your example but it does occur in some examples when both components are recombined the problem isn't apparent.

If you go through enough references you'll notice quite a few examples where isolation causes problems that are not there when everything is put back together either in full stereo or summed as mono.

I'll have to find a good example, I don't have one to hand at the moment but I've certainly come across it before.

Hey Bit, Have you checked ValhallaRoom Or Ubermod by listening in side mode? I'm just curious if they use phase differences to get the nice stereo separation on some of the presets; for instance DimChorus2 (which I really love)in Ubermod. I liked the wideness of both plugins, especially when I first got them. On my last mix, when I used Ubermod for rhythm guitar, it became very diffuse in the stereo field and not what I was looking for then. I don't think I listened to it in mono before I removed it or not. But it sure is fun to just jam around with it on my guitar. I don't think Valhallaroom is near as noticable in this aspect, because I have listened in mono with sometime 2 or 3 instances of it on my mixes. Actually, I guess I should check it out for myself huh! Doesn't the width in some form entail a delay and thus a phase shift? Or is the phase only a very small delay: A 1000 hertz frequency takes 1 ms per cycle, so a delay .25 ms is a 90 degree phase shift. Is my logic right?

I've only been using Ubermod for a short while, mostly for its chorus and ensemble effects, and can't comment on how well it maintains mono compatibility. Of course, any chorus-type effect involves recombining delayed signals, and the resulting comb filtering is what makes it sound like it does. I should really spend some time exploring Ubermod more.

ValhallRoom, OTOH, has become an old friend, being my go-to reverb that I end up using 80% of the time. VRoom's "diffusion" parameter is not equivalent to the Sonitus Reverb's "width" setting nor to the "diffusion" settings on other reverbs. The help text says it "controls initial echo density", but TBH I'm not sure what it really does. I know of no way to narrow VRoom's stereo dispersion using only its own controls.

Yes, you're right,  a 0.25ms delay is equivalent to a 90-degree phase shift at 1KHz.

Geeze louise, I thought Ubermod was a modulation plug to create chorusy phasey type sounds for effect, not for maintaining phase relationships while listening to the side component of a stereo mix.

Kelly Clarkson has a hit record so the production is crap because there is some effect on the hats?  Dern, all my productions and most popular music over the last 50 years must be garbage then.  You can be forgiven for perhaps not being a fan of Ms Clarkson, but she will have been put in the hands of somebody more skilled and experienced at the desk than yourself, there's too much money at stake with an act like that for her to be handled by an enthusiast such as yourself.  Some of the navel gazing and fart skinning that occurs here beggars belief sometimes.

If you are using some kind of modulation one would hope it would be because it works on the material you use it on otherwise leave it alone.  Don't use any kind of modulation on anything you want to maintain the fidelity of would seem to me to be a simple solution.  Otherwise crank them knobs to get whatever cool sound you are after.

As far as mono compatibility goes click the interleave button from time to time, I'm pretty sure Valhalla tried that a few times when they were designing Ubermod too.

I can't remember the last time I saw a bunch of young ladies stop dancing at a club because they were concerned about the disturbed phase relationships on a track caused by a modulation plug-in.  I do notice that even today if Itchycoo Park ever gets played they will say hey that drum bit sounds cool, whether it's a mono or stereo version.  I'll bet that sounds messed up when you listen to the side component too, that was the whole idea of flanging, it showed that comb filtering can be fun.  None of that kind of modulation is going to sound great if you are monitoring the side component in isolation, it ain't meant to be heard that way. 

If you are checking for mono compatibility simply listen in mono, listening to the side component is the last thing you'd want to do if you are checking for mono compatability.  It can give you insights into how a mix was put together, it can also indicate why a stereo mix isn't working but it will tell you nothing about mono compatibilty unless you hear it along with the mid component.

To clarify:

Soloing the side component is in fact collapsing to mono

Wrong!  This is in fact untrue.  On signals that are not specifically recorded in mid/side mode the mid component is everything that is panned center the side component is exclusively everything else.  Therefore listening to the side component in isolation isn't the mono mix.

With a true mid-side recording there is some overlap with the side component as it is usually recorded with a figure 8 pattern or omni directional mic to pick up the 'room' whilst the mid component is just recorded with whatever directional mic is picking up the target voice or instrument simultaneously.

As you can see then whichever type of source signals you are listening to in isolated side mode will be different to the summed mono mix.

There is no kick or snare, but cymbals and toms were surprisingly present. This tells me that the overheads contributed more to the toms than close mics, which I'd think would be atypical today.

Why would it tell you that if the close mics are panned off-centre which they clearly are in this instance?

Unless somebody is keeping a secret from me it's not atypical for the overheads to be the prominent basis of the drums still.  In fact on most commercial music these days you'd be lucky to hear anything other than the overheads and maybe the room from the original recording.  The rest these days is commonly used to trigger replacement sounds and has been for years.

Another variation of this listening technique is to split the mid and side signals and 'send' them prefade to seperate buses put another instance of channel tools or whatever you are using to mid/side encode and decode the components back to the individual stereo components but on seperate busses.

You can then switch between mid, the full width stereo component in isolation as well as combining them back into the full mix really quickly.  You can even choose send some of the side component back into the mono mid bus which can be a definite aid to mono compatibility in some circumstances.  Try adding some extra air to the sides and cutting some LMF mud with a separate eq there, try different comp settings on the mid and sides and such.

It's by taking all this stuff apart and putting all back together that helps make sense of it all.  You don't need an invite via Bob Ludwig to find out about this stuff.  Hey, you'd even find out how completely cool Cakewalk's Channel Tools is and what it's capable of...  Not only that purely playing around is fun.

My, we're feeling a little cranky today, aren't we, JB?

bitflipper


My, we're feeling a little cranky today, aren't we, JB?

Why do you say that?

I'm not as it goes.

Some of the things you were saying here just didn't make any sense in relation to the subject that you raised.  I felt some clarification was in order in case people interested in the subject of Mid/Side were left with the wrong impression.

Indeed it's a useful, and well-used staple for any mixer to understand the concepts of, not only for listening for mixing tips from old recordings but for gaining complete control over your wide and centered elements.

In fact there is a whole range of specialist plug-ins that one needn't purchase once you understand how mid/side encoding works and you are able to treat both components seperately by bussing them independently.  Especially as stereo source tracks are not uncommon these days with soft-synth patches and stuff that of course will require some management, Channel Tools is awesome for this task it covers every aspect you need whether it's encoding/decoding to/from mid/side or just being able to limit the width of these sources and to give you the ability put them exactly where you want just like a mono source.  I'd recommend an instance of it on every stereo track you have on a mix.  That fact that you were unaware of it's capability in this area rang some alarm bells for me, but there you go.

Colour me cranky if you like but I felt some clarification was in order here.  If however I have said anything inaccurate here feel free to correct me.

I should clarify: when you solo the sides in Ozone, the output is folded to mono. This is what I was referring to when I said that phase differences become apparent when soloing the Side component. This would not be the case if you're using Channel Tools or MSED to mute the Mid component.

BTW, there is an update to Voxengo's MSED available now, which features Mid and Side Mute buttons, making it more convenient for bouncing between mid-only and side-only listening.

bitflipper


I should clarify: when you solo the sides in Ozone, the output is folded to mono. This is what I was referring to when I said that phase differences become apparent when soloing the Side component. This would not be the case if you're using Channel Tools or MSED to mute the Mid component.

I'm still not sure of what is happening here that is specific to Ozone then.

If you listen to either the side or mid component on any MS decoded signal then each component is 'mono' (or rather a single track) whatever tool you use.

I still don't think you've understood that phase issues maybe inherent when listening to either the Mid or Side in isolation merely because the side has lost it's relationship with the mid component and therefore some phase issues are likely to be apparent because you have singled them out and may not (or indeed may) exist when the signals are recombined.

If you are in Mid/Side mode (which you are as soon as you simply click the input mode to M/S on Channel Tools without needing to touch anything else) the left channel is usually the mid and the right channel the side component.  So if you pan a send hard right to one bus and pan another one hard left then you have seperated out the two components.  Convert them back to stereo on the seperate buses with another instance of your encoding tool and you can hear (and treat) either in isolation. 
 
Every and any Mid/Side decoding/encoding matrix works the same way it's just that Channel Tools comes free in the box already and performs every task that you'd want for dealing with stereo whether L/R or M/S or switching between the two.  If anything else is happening then it ain't truly Mid/Side as defined by Jimbo's equation earlier.  In the digital domain tt's a simple logical switch on the signal to find what is Mid and what is Side and to convert back, it's always one thing or the other there is no interpretation or complexity involved.

bitflipper said: I should clarify: when you solo the sides in Ozone, the output is folded to mono. This is what I was referring to when I said that phase differences become apparent when soloing the Side component. This would not be the case if you're using Channel Tools or MSED to mute the Mid component.

I say: I don't get what you're saying here. When I solo the side in Ozone, I get exactly the same thing as turning down the Mid in Channel Tools.

I also don't follow some of your conclusions about the side signal, but I'm not sure since I don't quite understand what you're getting at. Say I have a signal--a vocal track for example. I have it panned dead center. I then take a stereo copy of it (stereo, but the 2 channels are just copies of the mono) delay it few milliseconds, then invert the phase of one of the channels. I also drop it down in volume (maybe have it -10dB) to sit back in the mix.

Now, when I listen to the Mid signal, all I get is L+R so the original vox is clear, and the delayed vox is completely cancelled out. When I listen to the Side signal (L-R), the original vox is completely cancelled out, and each channel of the delayed vox is summed together and played back crystal clear (at the level I dropped it down to, -10dB in this case) with no phase issues whatsoever.

Now consider a single track panned hard left, nothing in the right. The Mid (L+R) will just be a mono version of that track. The Side (L-R) will also just be a mono version of that track, and it will be exactly the same as the Mid. So in a track where everything is in the left, the Mid and Side signals will be exactly the same.

I think Jonbouy gets this right: "I still don't think you've understood that phase issues maybe inherent when listening to either the Mid or Side in isolation merely because the side has lost it's relationship with the mid component and therefore some phase issues are likely to be apparent because you have singled them out and may not (or indeed may) exist when the signals are recombined. "