User's Manual

User’s Guide ADI-2 Pro FS - v 2.5

34.22 M/S Processing

The mid/side principle is a special positioning technique for microphones, which results in a mid

signal on one channel and a side signal on the other channel. This information can be trans-

formed back into a stereo signal quite easily. The process sends the monaural mid channel to

left and right, the side channel too, but phase inverted (180°) to the right channel.

For a better understanding: the mid channel represents the function L+R, while the side channel

represents L-R.

During record the monitoring needs to be done in 'conventional' stereo. Therefore the ADI-2 Pro

also offers the functionality of a M/S-decoder. Activation is done in the Settings panel of the

Hardware I/Os via the option M/S-Proc.

The M/S-Processing automatically operates as M/S encoder or decoder, depending on the

source signal format. When processing a usual stereo signal, all monaural information will be

shifted into the left channel, all stereo information into the right channel. Thus the stereo signal

is M/S encoded. This yields some interesting insights into the mono/stereo contents of modern

music productions.

Additionally some very interesting methods of manipulating the stereo base and generating

stereo effects come up, as it is then very easy to process the side channel with Low Cut, Ex-

pander, Compressor or Delay. Looping this effect chain back into the DAW via AD-conversion

often a transformation back to stereo is missing. That's one of the reasons the ADI-2 Pro offers

M/S-Proc also in its analog input channels.

The other application is to split a single analog channel signal to both analog inputs, then acti-

vate M/S-Processing and analyze the digital left channel only. This method performs mono

summing, which raises the ADI's incredible SNR by another 3 dB for even better measurement

analysis capabilities.

But the most popular application in music recording is the manipulation of the stereo width: a

change of the level of the side channel allows to manipulate the stereo width from mono to ste-

reo up to extended (this feature requires an external mixer).