Topic: A device (or mixer) that monitors in decoded M-S but records discrete tracks

[RichT]

Lots of DIY MS decoding info here, including a couple of (really simple) Neumann circuits.  Might have a go at the Neumann Wheatstone Bridge and see if it'll fit in a jack

http://www.uneeda-audio.com/#ms

[Nick's Picks]

also, if it hasn't been mentioned, schoeps has a great vst plugin for their double MS rig.  works great for MS too

[Tommy-boy]

I have my rig set up to record in M-S, but to monitor the decoded signal.  I accomplish this with the following equipment:

R-44 
Art S8   http://www.artproaudio.com/products.asp?type=88&cat=11&id=137
Behringer Eurorack Pro RX1602    http://www.behringer.com/EN/Products/RX1602.aspx
Phase Inverters (I think they're whirlwinds) - hard to see behind rack at moment.
Cables that go from RCA to XLR (I think I have inexpensive Hosa cables for this).  This it to make connection from R-44 to S8.
Cables that go from XLR to TRS (Hosa).  This to make connection from Phase Inverters on S8 to Eurorack.
Cables that go from RCA to TRS (Hosa cables).  This is to make connection from R-44 to Eurorack.

I basically run the analog outputs of the R-44 into the Art S8 and Behringer Eurorack.  The only purpose of the Behringer Eurorack is to monitor.

Assumptions - Input 1 on R-44 is Mid (M) mic; Input 2 on R-44 is Side (S) mic.

Chain for Mic 1:  Into R-44 (Channel 1), out of R-44 analog out (Channel 1) to Eurorack Channel 1 (panned center)

Chain for Mic 2: Into R-44 (Channel 2), out of R-44 analog out (Channel 2) to Art S8 where channel is split.  We'll call these channels 2A and 2B.  2A goes to Eurorack Channel 3 (panned left).  Signal 2B hits phase inverter and then goes to Eurorack Channel 5 (panned right).  The reason for going to channels 3 and 5 with the side (S) signal is that the Behringer inputs are ganged in pairs of 2.  Using Channel 1 of the 1-2 pair causes 1 to be mono – which I can then pan center.  Using Channel 3 of the 3-4 pair causes 3 to be mono – which I can then pan left.  Using Channel 5 of the 5-6 pair causes 5 to be mono – which I can then pan right.

Voila - instant monitoring of decoded signal.  R-44, in the meantime, is recording a pure unadulterated M-S on channels 1 and 2.

Granted, The Eurorack is a little noisy.  However - It's not in the recorded signal path and helps me monitor what's going on.  I do the decoding of the M-S channel later in my Daw.  Just copy track 2 from R-44 (pan original left and copy to right).  I typically send the 2 side signals (L and R) to a group channel in Cubase so that I can raise the volume of the sides with one fader.  Not hard stuff.  By ear, I adjust the relative volumes (M versus S) to get the stereo spread to sound right.

By the way, you cannot accomplish this without a splitter that has a transformer isolated output.  A “Y” splitter won’t cut it (I learned this the hard way instead of thinking it through first).

One other tip for M-S recording: when I’m setting up, I have somebody walk from left to right in front of mics so I can immediately determine if I have the darned thing setup correctly.  I can do this as I mainly record school bands (always some time before concerts start to do this).

Hope this helps.
Tom

[Ozpeter]

I mainly record school bands (always some time before concerts start to do this).

Well, I have to say for that purpose it's really hard to justify recording separate MS signals, imho - I just don't see the point of the complexity of the rig you describe compared to the simplicity of recording your MS mics straight to XY in the R44 - nothing else required.  Vary width if required during post production using the method I've described.  I should add that most DAWs should be able to vary the width dynamically during the performance to taste.  For instance, say it's a fairly reverberant venue, and the conductor makes some introductions from the podium.  You might reduce the width close to mono for clarity's sake during the announcement.  Just as easy to do with an MS VST applied to an XY recording as with an MS recording - mathematically the same.