Calrec S2 Operator's Manual page 69

S2
.............................................................................................................................................................................................................................................
M = L + R
√ 2
S = L - R
√ 2
The advantage of course is that the M signal represents a mono reduction of L & R at an
appropriate level which is always a requirement.
The S series console channel inputs all have provision for M/S inputs and conversion back
to L & R via the M/S button to the formulae above.
5.5 DESK & LINE OUTPUTS
All Calrec consoles have Desk & Line Main Outputs both Stereo & Mono. This is
essentially a BBC technique where the alignment tone is injected after the desk outputs
and before the line outputs (which follow the desk outputs).
This is so that rehearsal can proceed whilst monitoring the desk outputs & simultaneously
sending a tone to line.
The Line output is the principal console output but Desk outputs besides being used as
above can be distributed to the Studio Loudspeaker and to other studios as required for
cue purposes.
5.6 STEREO IDENTIFICATION SYSTEM
The stereo identification system circuit can be seen in the CIRCUITS DESCRIPTION
section - No. 20, 2 sequences are available:-
1 EBU which interrupts the left signal only once every 3 seconds and does not
affect the right signal.
2 BBC "GLITS" system which interrupts the left signal once every 4 seconds and
interrupts the right signal twice in the intervening period. The period of the
interruptions is such that it can easily be seen on a PPM or VU meter or bargraph.
The button to initiate these sequences is found on the TONE (oscillator) section.
The sequences affect only the Main Output.
5.7 AUDIO GAIN RANGING
The S series consoles have a basic headroom of 28dB above standard line-up level 0dBu
(peaking at +8dBu). This approach produces an excellent noise performance throughout
a channel particularly in the equaliser section which can produce the bulk of channel noise.
The BBC and others in the past have required an input headroom of 32dB or even 36dB up
to the channel fader particularly in Outside Broadcast situations where an unexpected
input overload can occur and pulling back the fader does not remove the distortion.
69