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Re: M/S decoding help

Subject: Re: M/S decoding help
From: "Ed Anson" ed_anson
Date: Fri Jul 7, 2006 12:13 pm (PDT)
Dave,

Others have already answered most of your questions. I'll just add a 
bit to some items.

On Jul 7, 2006, at 9:34 AM, thxdave wrote:
>
> Also, assuming that you record the audio into separate M and S tracks,
> does it make any difference to the decoding process if I record in
> mono .wav as opposed to poly .wav files?

You can do either, but since you are editing in Bias Peak, I would 
suggest that you use the poly format. That will create a stereo file 
that you can easily edit in Peak. If you create two separate files, you 
will need an extra step to combine them into a stereo file before 
editing. Note that some other editors have the reverse preference.
>

> My final bit of frustration came last night when I tried to decode my
> first m/s files and play them back on my computer. I'm using Bias Peak
> 5.2 which includes a plug-in (mda Image) that SEEMS to decode m/s --->
> Stereo, but the files (sometimes) play back incorrectly. For instance,
> I did some "walk-around" tests where I set up my MHK's on a stand and
> I circled the mics with my 722 at the end of a 25' mic cable (Star
> Quad cable wired to XLR-5 ends) and recorded myself as I called off my
> relative positions (center, left, right, 1 o'clock, 2 o'clock, etc.)
> so that I'd have a good way of knowing whether the mics were working
> correctly or that I had wired my cable correctly. When I played back
> the files in my headphones using the 722's built-in decoder, my
> recorded positions were clearly audible and tracked perfectly as I
> moved around the mic array. However, when I played these same files
> later at home using Peak and the m/s decoder plug-in, nothing seemed
> to play back correctly without a LOT of futzing using the slider
> controls of the plug. Can anybody recommend a fairly simple m/s
> plug-in that I can use so I can make sure that I'm doing all of this
> correctly?

I also use the mda image plug-in with Peak, and it works quite well. 
However, it has one quirk that may be affecting you. The top slider 
controls the conversion performed. Unfortunately, it defaults to 
"LR->LR" which has no effect. You want to click it one notch to the 
left, which is "MS->LR". All of the other defaults are what you will 
probably want most of the time. Play with them a bit to see what they 
do, but usually keep the top slider at "MS->LR".

One interesting aspect of this plugin is that it also has an "LR->MS" 
option that allows you to convert a normal stereo file to M/S. You can 
then make any changes you want and convert back using another copy of 
the plug-in. This gives lots of flexibility that I seldom use, but it's 
good to know it's there if I need it.





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