M/S Recording

[recordingpro]

Hey guys, I've had a number of people lately asking me about a certain technique I use a lot, which is M/S stereo recording of instruments. In addition to getting a great stereo image that is completely mono compatible, it gives you a TON of flexibility and creativity in the mix. So-- I did a whole article on my blog about a number of different stereo recording methods, and did another whole article just on how much flexibility you can get in a mix when using the M/S method in particular. I won't restate the whole article here, but you can check out my blog (link below) for the article that I just posted, complete with some audio examples.


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Check out my Music and Recording Blog: http://recordingpro.blogspot.com

[cmchamp]

When able, I use MS for ensemble recording - wind band, orchestra, choral. Much warmer, natural sound.
C.

[Smithcok]

^^ Also awesome on a leslie

[aitikin]

The major fault I have with MS is that, yeah, it has wonderful mono breakdown, but when you listen in mono, it's literally just the cardioid (or omni/hypercardioid, whatever you're using) mic. If you put that on a choir close enough that the stereo sounds really good (obviously without the hall reverb, or the bleed from an orchestra), you'll get just the one mic. Sometimes it's better to work in pure stereo.

[recordingpro]

agreed. but again, as with anything, the key is to know when to use it versus other methods.

[TimOBrien]

I've been trying out M/S recording for my tenor sax and really like it...
Certainly worth trying if you need to record a horn player.

[yeahforbes]

I know this thread is rather old, but I happen to have explored into the actual physics of the M/S method and wrote up an explanation for teaching those who don't fully understand how it works. The common explanation is that stuff picked up from directly in front (into the cardioid) is panned center, and stuff from the figure 8 is added with one side inverted for "that huge wide sound" that comes from inverting one side of a stereo signal. Actually, there is more going on which causes sound originating from the left side of the stage to end up on the left side of your mix, and likewise for the right. That leaves the predominant difference difference between X/Y and M/S to be something you might not think of: say you're recording a band or choir -- does sound from the musician dead center hit a capsule on-axis (the Mid mic) or 45 degrees off-axis (each X/Y mic). Likewise, the musicians at the far edges of the ensemble will be either on-axis to a capsule (one of the X/Y mics) or 45 degrees off-axis (to all of the M/S capsules). That's a lot of words to get through, so I'll clarify if needed. Here we go...

The MS (Mid-Side) Microphone Matrix

The middle microphone (cardioid) produces positive voltage when it receives positive air pressure, whether that pressure is from the left, front, or right.

The side microphone (bidirectional, figure-8) produces positive voltage when the front receives positive air pressure and negative voltage when the back receives positive air pressure.

When the side microphone has its front facing left and its back facing right, sounds from the left produce very similar voltages on both mics because the front of the figure-8 and the cardioid mic are both producing positive voltage for positive air pressure. Sounds from the right produce nearly-opposite voltages because the cardioid is positive and the back of the figure-8 is negative.

Adding the two signals together results in sounds from the left being very prominent (combination of two in-phase signals) and sounds from the right canceling out (combination of two out-of-phase signals). This is sent to the left channel.

Flipping the phase of the side signal causes sounds from the right (hitting the back of the microphone) to now have positive voltage for positive pressure, just like the cardioid signal. Adding it to the cardioid results in sounds from the right being very prominent and sounds from the left canceling out. This is sent to the right channel.

These combinations are what occurs when the middle signal is panned center (sent to left and right), the side signal is sent to the left, and the inverted side signal is sent to the right.

When reproduced on a mono system, the side signal cancels out because it was inverted on the right channel, leaving only the mid signal audible.

[TimOBrien]

Nice explanation, but a picture is worth 1000 words:

http://www.wikirecording.org/Mid-Side_Microphone_Technique

[dpd]

Thing to keep in mind is that amplitude matching impacts the ultimate pattern that is obtained via mixing (as stated in the wiki); however, the relative frequency responses of the microphones used will impact the ultimate result, too.

I've never tried this one and don't know why... Gonna remember this for next time.

[cmchamp]

At this point, I've been using either an Apex 415 or Apex 460 for the figure 8 and an AT ATM450 for the cardioid.
I've been really happy with that, but can't wait to update to a StudioProjects LSD-2.
I've also been using the Art TubeFire8 and have also been pleased with that.
I record with Digital Performer, so the MS decoding is a snap.

C.