A question on M/S

P

Pische

New member
Hi everyone.
This is my first post, but I've read this forum a lot and I love it.
I'm working for film audio for the past two years and I intend to do it for the rest of my life.

I've read a very inspiring book, which is Stereo Microphone Techniques by Bruce Bartlett.
The most interesting technique is the M/S. It seems also one of the most used in film audio, so I've got a question:

is it true stereo?

I'm explaining myself better: let's say I'm recording a street ambience. If a motorbike makes motorbike noise on my left, the figure-of-eight mic will capture it, then, when I'm going to process the M/S signal, will the motorbike be both on the left and on the right?
 
Pische said:
Hi everyone.
This is my first post, but I've read this forum a lot and I love it.
I'm working for film audio for the past two years and I intend to do it for the rest of my life.

I've read a very inspiring book, which is Stereo Microphone Techniques by Bruce Bartlett.
The most interesting technique is the M/S. It seems also one of the most used in film audio, so I've got a question:

is it true stereo?

I'm explaining myself better: let's say I'm recording a street ambience. If a motorbike makes motorbike noise on my left, the figure-of-eight mic will capture it, then, when I'm going to process the M/S signal, will the motorbike be both on the left and on the right?
Click to expand...

It is true stereo. BOTH the figure-8 and the middle cardioid mic would capture the sound of your motorbike. Post processing involves mixing the two. First the figure-8 signal is duplicated to make two signals and the copy is phase inverted with respect to the original. The mid signal is then added to each copy - the sum of the original side signal and the mid going to the left channel and the sum of the inverted side signal and the mid going to the right. In your motorbike example, when it's on your left, its sound is reinforced in the resulting left channel mix and cancelled out in the right channel mix so you'll only hear it from the left channel speaker. As it moves over to your right, its sound starts to get reinforced less in the left channel and reinforced more in the right.
 
Thank you very much, you've been very clear.

Now I will think a lot about buying the Rode NT4 or save money for a good M/S setup.
 
Pische said:
Thank you very much, you've been very clear.

Now I will think a lot about buying the Rode NT4 or save money for a good M/S setup.
Click to expand...

High quality figure-8 pattern mics are generally a bit pricey. One could put together a primo M/S rig with a couple of Schoeps capsules, say a matched pair consisiting of a CCM8 figure-8 and a CCM4 mic, or a couple of CMC6 amplifiers with a MK8 figure-8 and a MK4 cardioid head. Such as setup would run about $4000 without mounts. Or you could use the AKG Blueline with a set consisting of 2 SE300B power modules, a CK94 figure-8 capsule, and a CK91 cardioid capsule. Together they'll run about $1400 for the pair.
 
There are also M/S stereo microphones built into one body. For example the venerable Shure VP88 (can be found used for around $500) and several short shotgun models from Pearl. Also Sennheiser, Sanken etc.

The Primus inter Pares M/S combination is Sennheiser MKH30 fig-8 and MKH40 cardioid or MKH50 hypercardioid combined inside on Rycote windshield. Lowest noise figures and best humidity tolerance of any mics. Not cheap.
 
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