Z-Systems z-Q2 - Manual (Page 5)

and all equalization and gains are set to 0 dB, the system remains perfectly bit
transparent, since its MS encoder and decoder are exactly symmetrical, down to
the last mathematical bit. You can leave the system in MS Y, Y mode if you wish
and operate it as a stereo equalizer without any concern for losses.
MS stands for Mid-Side, or Mono-Stereo. When in MS Y, Y mode, internally
the z-q2 becomes an MS-style equalizer instead of a stereo equalizer. However, the
input remains stereo and the output remains stereo. It is useful to know that an MS
encoder contains the same circuit as a decoder. This means that you can use the
encoder to decode and the decoder to encode if you wish. For example, you could
feed an MS signal into the z-q2, decode it to stereo, manipulate the left and right
balance and eq, and then reencode it to MS for further processing in MS mode.
There are about 16 permutations you could think of, so the limit of flexibility is
completely up to your imagination!
Taking advantage of M/S. The most common use of MS equalization is to
deal with center channel information which needs separate EQ than the sides. If
you feed a stereo recording into the z-q2 and set the mode to MS Y, Y, the left
channel gain control becomes the M gain (or center gain), and the right channel
gain control becomes the S gain (or side gain). These controls can manipulate the
width of the stereo image, while also reducing the ratio of the mix of center-located
instruments to side-located instruments. Try it. Feed in a good stereo recording
with a center-located vocalist. Press the GAIN button and turn the middle knob
counterclockwise until the L gain is at -95 dB. The vocalist (and all center
instruments) should virtually disappear, and you will be left with a widely-
separated, out of phase mono representation of the instruments and stereo vocal
reverb. See what happens if you turn down the R gain instead. For equalization,
you can cheat the frequencies for the M channel up or down separately from the S
channel to manipulate the recording in creative ways. All the L labels are
interpreted as M, R labels as S. In MS Y, Y mode there is no way to adjust full
channel balance because the L and R gain controls have become M and S controls,
respectively.
The presets (see below) remember the M/S state, so, for example, you can
work on one tune in MS mode and another in stereo mode.
This completes the SYSTEM Menu.
presets
Loading Presets. Press the presets button once to arrive at the load screen,
z-q2 Operations Manual version 1.0 1/2301 Page 5