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Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: yug du nord on September 25, 2009, 08:48:05 PM

Title: Mid-Side (M/S) post processing?
Post by: yug du nord on September 25, 2009, 08:48:05 PM
I recorded some mid-side this past summer for the first time and am finally getting around to processing it.  This is what I'm doing....  does it sound somewhat correct?

>Load raw files into DAW (mid=left, side=right)
>copy the side channel and invert it
>mix mid channel with side channel and the result = Left Channel
>mix mid channel with inverted side channel and the result = Right Channel.

And to determine the stereo spread, raise or lower the gain of the side/inverted side before mixing with the mid channel.

Sound about right?

Whether this is the correct method or not, I'm really diggin my results...  great localization of instruments.

Thanks!


Title: Re: Mid-Side (M/S) post processing?
Post by: page on September 25, 2009, 08:51:46 PM
Yeah, that will work (and is the correct process).

I like to dupe  (without invert) the mid to make a 4th raw channel and pan the mids to their respective sides as I find the control is a little easier to mentally handle, but it doesn't affect the results to not do that. The overall "adjust gain to adjust stereo pattern/angle" is the same process.
Title: Re: Mid-Side (M/S) post processing?
Post by: yug du nord on September 25, 2009, 08:57:32 PM

I like to dupe  (without invert) the mid to make a 4th raw channel and pan the mids to their respective sides as I find the control is a little easier to mentally handle, but it doesn't affect the results to not do that. The overall "adjust gain to adjust stereo pattern/angle" is the same process.

Cool man....  I "dupe" it too...  just didn't know how to say it without it sounding confusing.  Thanks bud!!!
Title: Re: Mid-Side (M/S) post processing?
Post by: boojum on September 25, 2009, 09:10:09 PM
http://www.voxengo.com/product/msed/

Free, easy, and it has on-the-fly adjustments to spread.  Hard to beat that.
Title: Re: Mid-Side (M/S) post processing?
Post by: yug du nord on September 25, 2009, 09:48:45 PM
http://www.voxengo.com/product/msed/

Free, easy, and it has on-the-fly adjustments to spread.  Hard to beat that.

I've dL this in the past, just to have....  but I've never been able to install it or open it...  are there any tricks to "unpack" it into Sound Forge?
Title: Re: Mid-Side (M/S) post processing?
Post by: stevetoney on September 25, 2009, 09:51:40 PM
...as others have said, that's about right Guy. 

Alternatively, most DAWs have a selection that does most of the work for you.  For example, in Audition 1.0, you simply load the raw footage and then select Effects - Amplitude - Channel Mixer - LR to Mid-Side.  Make sure the new right channels are fully panned opposite each other (one at -100% and one at +100%) and then mix the new left channel by varying the percentage to taste.
Title: Re: Mid-Side (M/S) post processing?
Post by: page on September 25, 2009, 09:59:48 PM
Yeah, 90% of your audio proggies will do it for you, some allow you to adjust the spacing while previewing.

I do it manually not because I walked up hill both ways in the snow as a child (I did, but thats a different story), but because for a long time in Audacity on the mac, the VST plugins didn't work properly and I was too cheap to pay for a real program and couldn't find one as an AU format.

Now there are some, and I just don't care.
Title: Re: Mid-Side (M/S) post processing?
Post by: boojum on September 26, 2009, 01:25:57 AM
http://www.voxengo.com/product/msed/

Free, easy, and it has on-the-fly adjustments to spread.  Hard to beat that.

I've dL this in the past, just to have....  but I've never been able to install it or open it...  are there any tricks to "unpack" it into Sound Forge?

It's a plug-in.  Drop it in the plug-in folder and then go through the routine in SF that enables plug-ins.  I use SAM and that is how I do it there.  I am assuming you are on a MS platform.  If you are no, all bets are off.  Good luck.
Title: Re: Mid-Side (M/S) post processing?
Post by: yug du nord on October 15, 2009, 05:48:00 PM
Another question for y'all....

After I do the M/S processing in post, my right channel's wave file is much smaller than the left.  Visually, the right channel peak levels are a good 6-8 decibels lower than the left channel.  But audibly, the sound has a proper stereo image.  Is this normal?  When looking at the files in SoundForge, why is the right channel much smaller looking?

Thanks again.
Title: Re: Mid-Side (M/S) post processing?
Post by: stevetoney on October 15, 2009, 05:55:06 PM
Another question for y'all....

After I do the M/S processing in post, my right channel's wave file is much smaller than the left.  Visually, the right channel peak levels are a good 6-8 decibels lower than the left channel.  But audibly, the sound has a proper stereo image.  Is this normal?  When looking at the files in SoundForge, why is the right channel much smaller looking?

Thanks again.

I've tried to figure out logically why this happens.  I haven't figured it out though.  All I can say is that the same thing happens to me more than half the time I do M/S and I use Audition, so I have no idea if that gives you a warm fuzzy or makes you feel less confident...after all I am partially insane  :drunk:...but I do have similar experieces. 
Title: Re: Mid-Side (M/S) post processing?
Post by: page on October 15, 2009, 08:12:50 PM
Yeah, it happens more often then not. Thats the most I've ever heard it off though without causing an imbalance in image. I've had mine be off by 3, maybe 4, but thats it. If it sounds balanced I wouldn't worry about it.