Owner manual

Blumlein's microphone techniques have advantages over all others (X-Y and A-B)

such that it is worthwhile using M-S microphones even when mixing is to be done ithe

L-R domain. For example, the M-microphone will be placed in the optimum position

for a mono image, whereas mixing to mono the signals from an X-Y stereo pair

introduces phase anomalies.

When using M-S microphones we suggest, for convenience, that M-

microphones are inserted in odd-numbered channels, and the corresponding S-

microphones are inserted in the next channels above.

Many are the tricks one can perform in the M-S domain, but the only one considered

here is the possibility of changing the width of a L-R stereo signal. Should readers

wish to investigate further M-S techniques, they are invited to request a copy of

the M-S Handbook written for our PORT-A-FLEX units AD066-11, M-S stereo

microphone amplifier and AD066-12, M-S post-production matrix amplifier.

AD146 will accept any combination of M-S and X-Y microphones and mix them in

either the M-S domain or the L-R domain. Therefore the outputs from the mixer may

be in either the M-S or L-R domain. The two domains can be combined to produce

eight possible mixing paths; of these, the following three are the most commonly

used:

(a) M-S microphones (with or without X-Y microphones) mixed in the M-S domain:

output M-S or L-R.

(b) M-S microphones (with or without X-Y microphones) mixed in the L-R domain:

output L-R.

When mixing in the L-R domain and using one or more M-S microphones, the

panpots on M- and S-channels will be centred and the S-switch selected on the

S-channel to create a matrix across the M and S channels. With CH (1) selected

on the monitor module, MON on an M-channel will audition the M-microphone on

monitor 1 L & R (and headphones L & R) outputs. When 'setting up' M-S

microphones, an S-microphone may be auditioned in a similar manner - BEFORE the

S-switch (15) is selected. After selecting the S-switch (for S-microphones only),

the complete M-S microphone may be monitored - automatically in L-R stereo. The

potential of such a microphone may be checked by changing the M/S relationship, ie

by varying the input gain of the S-channel. To monitor an S-channel after the S

switch has been selected, CH (1) will reveal +S on monitor 1 left and -S on monitor 1

right - not very useful. To overcome this difficulty, reduce the right output to zero

and select MONO (14) in order to isolate the in-phase component from the S-

channel. Spot microphones will be panned to their correct position in the final

L-R image, and may be monitored as non-destructive solo-in-place or as true AFL.