Stereo Expander Question...

B

BobOC

New member
Hi...

My bandmates and I took three of our "final mix" tracks to a friend's house yesterday...he has WaveLab, and we wanted to master the songs.

Everything sounded terrific WaveLab, really full of life. The one stumbling block was that the lead vocals fell back down in the mix too much when we applied stereo expansion. I love the way the expansion effect spreads the sound out...so we're going to go back and do alternate mixes with the vocals up a few dbs.

My question...can anyone give me a simple, yet "scientific", explanation as to why the vocals recede in the mix when it is expanded? I have a general idea...just curious to hear the input of others. Thanks...Bob.
 
I believe that this is because the expanders work by changing the phasing of the L/R tracks. This could likely cause some frequencies in the center of the stereo spectrum to be cancelling each other out to some degree. Increasing the volume is probably not gonna help this.

Purists will tell you to forget the expander and get there through the use of panning in the mix.
 
I'm not even a purist and I'd say that.

There are some relatively complex ways of messing with the stereo image that minimizes (actually slaps the face of) problems like that, but it's nothing I'd want to get in to here... I've spent around 10 years working on imaging. It's not something to jump in to.
 
dachay2tnr said:
I believe that this is because the expanders work by changing the phasing of the L/R tracks. This could likely cause some frequencies in the center of the stereo spectrum to be cancelling each other out to some degree. Increasing the volume is probably not gonna help this.

Purists will tell you to forget the expander and get there through the use of panning in the mix.
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Exactly, one of the ways of making things wider is to remove what's in the middle. A simplistic way of thinking about this is that stereo expansion is adding out of phase mono material to cancel out the center. Since your vocals are in the center, they will be lowered (probably along with the kick and snare too).

I would recommend getting the mix right rather than using tricks, but if you can't remix another way of widening is to delay one side by approx 10-15 ms. Search for articles on Haas effect for explanations. This method will not have the effect of center material being reduced in volume.
 
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C_Superstereo is a pretty fast way to play which the center and side elements of a stereo mix, it gives you a good visual of what you're doing too:

http://ourworld.compuserve.com/homepages/NickWhitehurst/cplugs.htm

PSP has a stereo analyzer tool that lets you see the relationship of the sides to the center for rebalancing purposes. Many good audio editors have some type of tool like that and I'm sure you have one too. PSP also has a delay type expander but I hear artifacts in their stuff or the method - either one.

You can even bust the m/s components out and rebalance that if you like...
mda image and other folks have tools for that.

Voxengo has recently added m/s capability to some of their plugs so you can process the mid or side individually which affects the stereo field greatly - Soniformer2 compressor and CurveEQ EQ both have it. Digitalfishphones Endorphin compressor has had this for some time. The Adobe Audition 1.5 update has some improved tools for this although they don't acknowledge the m/s part of it - it's like 'vocal removal' and 'vocal only' referring to the ability to manipulate either the middle or side channels. It's getting more popular no question.

After all that though I'd have to say the best thing to do is get is right in the mix cause it takes a lot of time to fool around with rebalancing anything after the mix. So instead of making music or mixing - you're editing and repairing !

I can believe it takes a number of years to get this technique down - along with some pretty good equipment and monitoring. I'm not very good at it so far - it's more like a science project :D
 
Thanks for the feedback, everyone...I appreciate it!

One more question...It sounds as if you're all pretty unanimous in advising against using stereo expansion....just curious as to why Sound Forge, WaveLab, et al would include it in their bundles? Is there a "correct" application for this effect?
 
BobOC said:
just curious as to why Sound Forge, WaveLab, et al would include it in their bundles?
Click to expand...
Just because something exists, doesn't mean it A) is useful; B) should be used; C) does what you think it should do; D) all of the above

;)
 
BobOC said:
Thanks for the feedback, everyone...I appreciate it!

One more question...It sounds as if you're all pretty unanimous in advising against using stereo expansion....just curious as to why Sound Forge, WaveLab, et al would include it in their bundles? Is there a "correct" application for this effect?
Click to expand...

Possibly to convert a mono source to pseudo-stereo, or when you can't remix (e.g. mastering some one else's material).

A lot of manufacturers (and consumers) feel that if there are lot's of bells and whistles a product will sell better or is better.
 
I think all that stuff is useful and fun and time consuming.

But you have the tracks in your hands - it can be remixed. It's best to get the stereo field and soundstage set in the mix instead of trying to re-adjust it downstream during post-mix or mastering or whatever you might call it - IMO.

I tweak the stereo field on certain tape transcribes but I don't have the tracks to remix like masteringhouse mentioned.

Aside from my ramblings about VST plugins I'd like to know how Bob Ludwig and the like adjust the stereo field - if and when they need to. What equip, etc. Massive Master might even have more to say about this - if we poke him a little... :D
 
kylen said:
Aside from my ramblings about VST plugins I'd like to know how Bob Ludwig and the like adjust the stereo field - if and when they need to. What equip, etc.
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You don't even need a plug-in to perform stereo expansion, just an understanding of how mid-side processing works.

Considering Bob Ludwig's clients I doubt that he needs to perform stereo expansion very often. Also, there are different ways of using M/S processing, for example with an EQ and compressor. The most often pieces of gear that I've seen in mastering are from Z-Systems, Weiss, Waves (for plug-ins), and some of the multi-functional boxes like the DBX Quantum and the Finalizer.
 
masteringhouse said:
You don't even need a plug-in to perform stereo expansion, just an understanding of how mid-side processing works.
Click to expand...
I begin with a stereo track and work only in a DAW. Don't I need some kind of software encoder/decoder or a plugin that does m/s internally (encode to m/s-->process-->decode to stereo)?

How else could I manipulate the stereo field using m/s techniques? I guess maybe you're talking about inverting the phases directly according to the m/s formula? If I use mda Image I don't need to do that but now I'm wondering what the difference in sound might be so maybe I'll try that again. Is that what you're talking about ?
 
kylen said:
I begin with a stereo track and work only in a DAW. Don't I need some kind of software encoder/decoder or a plugin that does m/s internally (encode to m/s-->process-->decode to stereo)?

How else could I manipulate the stereo field using m/s techniques? I guess maybe you're talking about inverting the phases directly according to the m/s formula? If I use mda Image I don't need to do that but now I'm wondering what the difference in sound might be so maybe I'll try that again. Is that what you're talking about ?
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Yep, talking about doing m/s processing manually.

One of the nice things about doing it that way is that you have more control and options than a plug-in. For example you could potentially automate the mid information if a vocal needs to come up/down in a certain section (thought other parts will be increased as well unless you EQ specifically). Also you have the ability to use m/s compression and m/s EQ techniques (like the Weiss EQ1).

Opens up alot more possibilities for doing new things, and screwing things up! :)
 
Thanks for the m/s tips masteringhouse.

I'm not in the weiss catagory but m/s processing is beginning to appear in all kinds of plugins now, I've got a bunch - and it's in Bob Katz Mastering book which everybody and their brother are waving around right now.

I guess I'm thinking it is becoming popular among the home recording project studio types even though the technique has been around for a while. Seems like fun so far but I'm still trying to get it to sound more natural... :cool:
 
masteringhouse said:
Yep, talking about doing m/s processing manually.

One of the nice things about doing it that way is that you have more control and options than a plug-in. For example you could potentially automate the mid information if a vocal needs to come up/down in a certain section (thought other parts will be increased as well unless you EQ specifically). Also you have the ability to use m/s compression and m/s EQ techniques (like the Weiss EQ1).

Opens up alot more possibilities for doing new things, and screwing things up! :)
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hehe, I finally broke out all permutations of my mix into seperate tracks and have found that balancing this way really sounds a lot better on this particular piece - I am using much much less compression to beat it into shape. :D

On seperate tracks I've got: the full mix, Left, Right, MID, SIDE, Vocal cut (from Adobe Audition), and Mono. Mixing in various levels of each track along with some SIR room enhancement really did it. Now with about .5dB of compression (Soniformer2) and minor adjustment with Elephant Mastering Limiter this piece has some life and balance.

This manual breakout is superior to my using the m/s tools to encode/decode IMO and gives more flexibility to make things better or possibly worse (as you say). And the secret - if there is one besides experience - is in the experimenting and tweaking - and being in a monitoring position where I can hear .5dB changes.

Thanx :cool:
 
interesting im supprised no one hear has dissed waves s1 plug in. I for 1 love that thing to create a nice stereo image on tracks for examples drums or background vocals. Not the master fader ,but i have used it on the master fader with good results as well, just less is more and i start in mono with it on the master fader and use the width of the panning vs the plugin that works nicely when pro tools wants to shrink the stero image on mix down though i think i may have found somthing better.

also have you checked your mix in mono? You may have phase problems that would be more evedent when messing with the stereo imagie. For example a stero reverb on the vocal drownding out the mix in mono when spread will shrink the main vocal and bring up the verb even more etc.
 
Bulls Hit said:
Kylen
what exactly are Mid, Side, Vocal cut & Mono?
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Hi Bulls, I'm out on a road trip and don't have my...oh yes I do here's my Bob Katz Mastering book, hehe. Off the top of my head though...given a stereo mixdown - MID is the mono component, SIDE are the sides such that when you either feed it into a M/S decoder or do it manually as we were talking above the Left and Right stereo components are created relative to the MONO component - 90 degrees out of phase with each other.

You can hear this pretty clearly when you sit in your monitoring triangle and find the center of the stereo field, use a plug like C_SuperStereo and pull the center down a couple of notches, move your head slightly to the left, then slightly to the right. As you pass thru center you'll hear the phase change - it's pretty obvious and interesting phonemon that way. Then when you adjust the center back to where it was and hit the mono button that will 'fold' in the sides (since they're 90 degrees out of phase with each other) and you'll just hear the MONO piece.

Vocal cut and MONO are presets that Adobe Audition (Cool Edit) uses to extract the sides and mono components of the stereo field. I was playing with this since once you isolate the components it's very interesting to mix them all back in a various levels to expand or collapse the stereo field as needed.

ED: I'm not sure if it's 90 or 180 degrees off the top of my head - I've got the formula on a paper I wrote...maybe one of the mastering guys will mention it - I gotta checkout of the hotel now though, later !
 
I have a stereo reverb function and it expanded my mono solo track. It out of a multi function box - SE-50. Seemed to help. I also posted it on nwr on a test track before and after.
 
ive used the stereo expander plugs before and they always geek my mix.
i dont use em anymore.
my mixes sound plenty stereo as they are.
 
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