Topic: Schoeps Mid-Side

[KLowe]

prolly a dumb question but....anyway.

Is there any use for double M/S in a typical PA oriented rock show?  What benefit would a rear facing M/S provide? 

This is probably oriented for orchestral arrangements where double M/S could be setup in the center for a surround sound signal?  I've been tempted to run double M/S but don't think it could add anything to the shows that I typically tape.

any input from the more experienced?

[DSatz]

KLowe, the advantage of the double M/S approach is that it overcomes the one most frustrating thing about conventional M/S. When you're playing back or transferring the recording as L/R stereo and you want to set your preferred stereo image width and the amount of reverberant sound in the mix, with regular M/S these two factors are always linked, since you have only one independent variable to play with--the relative amount of S signal going into the matrix. The more S you send in, the wider the stereo image will be and the more reverberant sound you will be reproducing. In my experience with regular M/S recording, there usually has only been a rather narrow range of S gain settings that have sounded at all plausible in stereo.

With double M/S the two factors are independent of each other, since the amount of signal from the rearward-facing cardioid is an independent factor. So the (somewhat more complex, software-based) matrix lets you vary the stereo image width independently from the direct/reverberant sound balance. It's like being able to choose both the geometry and the directional pattern of a coincident microphone pair after the recording is in the can.

--best regards

[KLowe]

Do you have any literature with pictures?  I've read your post about 10 times now and am still trying to wrap my little brain around it.

[Brian Skalinder]

I've read your post about 10 times now and am still trying to wrap my little brain around it.

I'm trying to wrap my head around this, too.  Simply having control of how much rear-facing Mid to add would only allow one to, well...add reverberant sound.  So I assume in decoding double MS it's possible to subtract the rear-facing Mid from both the forward-facing Mid and Side.  So in double MS, the ratio of the rear-facing Mid to the front-facing Mid and Side (and whether one's adding/subtracting it to/from the other signals) control the reverberant sound, while the ratio of the front-facing Mid to Side controls the stereo width.

The attached image generated with the Schoeps Double MS plug-in may help.  It's a two-dimensional representation of the mics and patterns in play:  orange = forward-facing cardioid Mid;  yellow = figure-8 Side;  green = rear-facing cardioid Mid.  If my assumption above is correct, and you're able to visualize it from the image, you may see how subtracting the rear-facing cardioid would significantly reduce the reverberant sound.

Hopefully DSatz will chime in with further clarification.  Neat stuff!

[KLowe]

Brian,  Your description of what is happening makes complete sense to me.  Let me try to explain it to myself.  -- for a PA taping...forward facing event.  The rear M/S is present as subtractive only to cancel out reverb sound from the intersecting side lobes and the intersection portions of the cardiod mics?  ie..."cleaning up" the forward facing M/S signal?

Does this seem like the "gist" of it?

DSatz?

Kevin

[Brian Skalinder]

Brian,  Your description of what is happening makes complete sense to me.  Let me try to explain it to myself.  -- for a PA taping...forward facing event.  The rear M/S is present as subtractive only to cancel out reverb sound from the intersecting side lobes and the intersection portions of the cardiod mics?  ie..."cleaning up" the forward facing M/S signal?

Does this seem like the "gist" of it?

That's the gist of it, but again...it's only my guess.  Hopefully DS or someone else can confirm, correct, or clarify.

[Stagger]

Save for the difference in frequency response between a Fig8 and a normal directional (card, subcard...etc.., I'm just wondering how this would be better than just turning a blumline rig on its side and running it through a ms decoder. Certainly an easier set up, no?

[Brian Skalinder]

Save for the difference in frequency response between a Fig8 and a normal directional (card, subcard...etc.., I'm just wondering how this would be better than just turning a blumline rig on its side and running it through a ms decoder. Certainly an easier set up, no?

Figure-8s Mid-Side and decoded 50/50 becomes Blumlein.  Changing the ratio of Mid to Side during decoding just changes the included angle of the resulting figure-8 patterns; it doesn't change the resulting stereo L/R figure-8 patterns.  The attached image shows a pair of figure-8s set up Mid-Side and the resulting sum and difference (L and R channels) after decoding to stereo.  You can see how the different ratios simply change the included angle, and not the resulting pattern.  (Table lifted from a paper posted earlier in the thread.)

Single MS with figure-8s allows the user to adjust <a> the front and rear lobes of the Mid channel together, and <b> the left and right lobes of the Side channel together.  Double MS with forward-facing cardioid Mid, rear-facing cardioid Mid, and Side figure-8 allows the user to adjust <d> the front Mid independently, <e> the rear Mid independently, and <f> the left and ride lobes of the Side together.  It's this ability to independently adjust the rear Mid channel that allows one to control reverberant sound separately from stereo width.

In single MS, any reduction of the orange Mid's rear lobe signal would also reduce the orange Mid's forward lobe signal (see attached single MS image ms-single-schoeps.jpg).  In the attached double MS image (ms-double-schoeps2.jpg), you can see that I've reduced the green rear-facing Mid relative to the orange front-facing Mid and yellow Side.  It's this independent control of the rear-facing Mid in double MS that allows one to adjust reverberant sound independently of stereo width:  adjust the rear-facing Mid to control reverberant sound, and adjust the Side to control stereo width.  Again, I'm assuming a lot here, and need to dig a little bit to make sure my assumptions regarding the rear-facing mid and decoding are correct.

[Nick's Picks]

cool.
sort of Sounfield-esque

[F.O.Bean]

KLowe, the advantage of the double M/S approach is that it overcomes the one most frustrating thing about conventional M/S. When you're playing back or transferring the recording as L/R stereo and you want to set your preferred stereo image width and the amount of reverberant sound in the mix, with regular M/S these two factors are always linked, since you have only one independent variable to play with--the relative amount of S signal going into the matrix. The more S you send in, the wider the stereo image will be and the more reverberant sound you will be reproducing. In my experience with regular M/S recording, there usually has only been a rather narrow range of S gain settings that have sounded at all plausible in stereo.

With double M/S the two factors are independent of each other, since the amount of signal from the rearward-facing cardioid is an independent factor. So the (somewhat more complex, software-based) matrix lets you vary the stereo image width independently from the direct/reverberant sound balance. It's like being able to choose both the geometry and the directional pattern of a coincident microphone pair after the recording is in the can.

--best regards

with the Schoeps Double M/S Plugin tho, would this still be effective in regular MS Or with that new plugin, you can alter the Mid in relation to the rear mid and not have it add/subtract to the signal youre working with.....

[wklitz]

I have borrowed a M/S rig numerous times...  The owner had a 21H doing the mid and it was really nice.  The slight emphasis on the high's was welcome and helped keep things centered very well.

I used a 21H when I did M/S recordings in '97-00, on occaision I would work with a different Mid capsule, once at Phish @ the Flynn in '97 I used a 41 as the mid channel with good results.  probably the best M/S recording I ever made was Allmans a few days prior to that at the Beacon.  sold all that stuff off when I bought my TLM-170's, which are now also sold off.  might have to try some M/S with my 414's one of these days.

[scb]

i just wish DPA would sell a figure 8. 

[Dr.FOB]

Very cool concepts raised in this thread.
A specialized application of multi-mic recording.

The schoeps native B-format arrangement, and it's lower cost AKG complement, are used to capture surround recordings to be decoded via software in post.  This is a double 8 front & side (x & y), with an omni (w).  This is the same concept as the Soundfield capture, but without the Z information. 



A lot of useful info, and some highly technical explainations, are here.

http://www.ambisonic.net/

Two cards and an 8 gives you the double m-s configuration, from which you can derive surround information. 



You can get the double m-s decoding plug-in from Schoeps here:
http://schoeps.de/dmsplugin.html

I've enjoyed making some 5.1 mixes in the past with a combination of M-S and subcards and look forward to trying the double m-s when the app arrives and I can figure out a mounting arrangement for the nuemanns.

[F.O.Bean]

All of this info is JUST what I needed to read before I get a fig8 cap Thanks guys!

[BayTaynt3d]

I wonder how an AKG394 would sound as my side when combined with a 481/2/3 as my mid? That might get me into the game for cheap. I knew I'd regret selling off my 390s...