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MS stereo recording and ms matrix decoding.

Discussion in 'Recording' started by mhuang, Aug 26, 2005.

  1. mhuang

    mhuang Guest

    I am planning to buy a sennheiser MKH 418S shotgun mic which records MS stereo. I am planning on using the mic with my Tascam DA-P1 DAT recorder which only has L/R XLR input and I read somewhere that in MS stereo records M signal to the L channel and the S signal on 2 other channels and later combine in post production to create the stereo sound file.

    My question is, do I need a dat recorder with 3 inputs to be able to record in MS stereo?
    I am also a bit confused about the whole MS matrix decode/encode process, can anyone explain to me how it works? do the recording hardware have to support this or can I do it via software/plugins?

    thanks.
     
  2. David French

    David French Well-Known Member

    All you need is two channels to record MS. To matrix this to stereo, the 'S' channel is duplicated and phase inverted, creating the third channel. The two 'S' channels are panned opposite directions and combined with the M channel which is panned cneter. Varying the relative balance between the 'M' channel and the 'S' channels allows you to adjust the width.
     
  3. mhuang

    mhuang Guest

    hi, David,

    is the matrix process automatic or do I have to manually do this?
    and how do I adjust the balance between M and the S channel if the S channel is mixed into the M channel?

    thanks
     
  4. David French

    David French Well-Known Member

    Check your recorder's manual and see if it had a built in MS matrix. Some do, some don't. If not, you can set up the matrix yourself after dumping digitally into your favorite DAW.

    The channels are separate, but you route them out of the same bus. You have one 'M' channel and a pair of 'S' channels as I described before. Play the 'M' channel at 100% and then bring in the 'S' pair until you think it sounds right. If these three channels are sent to a stereo bus, then they are now stereo and you can export or record the output of this bus as your finished stereo mix.
     
  5. aztec

    aztec Guest

    You can also have a look at MSED, a free plugin, to get a better understanding how the whole process works.

    Link

    and info
    MSED is a mid/side encoder/decoder plug-in which encodes (splits) the incoming stereo signal into two components: mid/side or, alternatively, mono/stereo pair, and vice versa: decodes mid/side signal pair into stereo signal. MSED is also able to work in the in-line mode with the ability to adjust mid and side channels' gain without the need of inserting two MSED plug-ins in sequence.

    Take care
     
  6. Looking at the information at http://www.paia.com/msdecwrk.htm helped me to finally figure out how it all worked.

    Sometimes I just need a picture.
     
  7. mhuang

    mhuang Guest

    thanks the explanation everyone, I think I am finally got it through this thick skull of mine. :D

    @james
    that links a bit more technical, I found another link that explains it pretty straight forward:
    http://www.transom.org/tools/recording_interviewing/200106.stereomicrophones.jtowne.html

    thanks guys!
     
  8. fatbot

    fatbot Guest

    hey,

    I am also looking into field recording via MS stereo recording, and I have some questions I hope you kind folks can help me with. :lol:

    I've heard that you can't can't monitor the incoming ms signal unless you have a decoder to decode the signal into stereo, but if you use the decoder to decode the incoming signal into stereo does the portable recorder capture only the decoded stereo signal or does it still captures the original MS signal?
     
  9. David French

    David French Well-Known Member

    It should capture the MS. The decoding should be done just through a monitoring path.
     

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