Audio Developments AD149 - Manual (Page 9)

8
M-S NOTES
GENERAL BACKGROUND
Of the various techniques that have evolved for stereophonic recording, the so-called
COINCIDENT, NEAR-COINCIDENT and SPACED-APART techniques have found
favour in the recording of classical music - being better suited to preserving natural
perspectives and balances; whereas for the recording of popular music, the favoured
technique is one which uses many microphones closely positioned to their sources for
maximum isolation.
Increasingly, it is being realised that, of the coincident microphone techniques, the
rediscovered M-S (middle-side) technique has many advantages over the other
coincident techniques, particularly when working in unknown or difficult situations.
Several leading manufacturers are now producing integrated M-S microphones, but
many are of the electret variety exhibiting typical frequency-response aberrations.
Our own extensive research and experimentation have shown that the highest quality
and maximum flexibility are obtained when using the new generation of discrete, true
condenser microphones. An extremely high quality M-S system can, for instance,
be assembled from the new SENNHEISER range of studio condenser microphones
(MKH20,30,40,50,60,70) together with the MZD30 which clips two microphones
together in 'piggy-back' style and aligns the capsules in the same plane. (It should be
noted that these microphones use RF technology and therefore offer high immunity to
moisture in the atmosphere.) With such a system, not only can the most suitable
choice be made for the M-signal microphone - omnidirectional, cardioid,
hypercardioid, (short-gun, long-gun) - but also, there is no requirement for extra
microphone powering units and/or matrix amplifiers as AD149 is able to supply all the
control necessary for professional, stereophonic recording and post-production.
For stereo TV and film, M-S is the obvious choice; it permits the easy matching of
audio and visual images - focusing performers in the centre of a wide 'stage' or
expanding the stereo image and adding ambience on 'long shots', and, if mono
compatibility is of great importance, this format is the clear winner. (The majority of
the listening audience still hears a mono mix.)
It has been shown that more ambience is preferred when listening in stereo than
when listening in mono. Recordings made using the M-S technique satisfy these
preferences as the presence of the S-signal increases ambience with the M-signal
being true mono. Because of the way the pair of microphones responds to
reverberant information, a well done M-S recording preserves a high degree of
realism.
When using the M-S technique, the microphone system can be positioned in order
that the forward facing capsule produces the optimum mono signal with the best
possible frequency response whilst maintaining easily adjustable stereo perspective