Alesis M1 Active Mk2 Manual De Referência

While most speaker systems for monitoring music in surround use the same
speaker cabinet in all positions, both front and rear, keep in mind that most
consumer video surround installations use a different speaker in the rear
channels.  These rear speakers typically do not have the same directionality or
wide frequency response of the M1 Active Mk2s.  When mixing for film,
speakers with a broad ambient, non-directional response are used to mimic
the multi-speaker situation in most movie theatres.  Keep this in mind when
making music mixes with full-range high-power speakers like the M1 Active
Mk2s as the surround speakers.

The difference between music surround and video surround playback has a
long history:

•  Dolby Pro Logic, which works best with dipole (i.e., speakers splayed in

different directions out of phase) surround speakers, has been the
standard for surround sound in the home for 10 years.

•  The most accepted home playback medium, VHS videotape, can only play

back (mono) surround in Dolby Pro Logic. VHS will not support Dolby
Digital or DTS.

•  There are only two playback mediums, laser disc and DVD, that support

Dolby Digital (discrete) and DTS (discrete). After 20 years in existence,
laser disc has only a 2% market share.  Some digital satellite broadcasters
have started broadcasting in Dolby Digital, but these discrete broadcasts
will be reserved for blockbuster movies initially.

•  Discrete Dolby Digital, DTS and Sony’s SDDS are most commonly mixed

for theatrical release using surround, not monopolar (direct) monitors.

•  Among the recording engineers who have recorded audio-only, the

consensus seems to be that the role of the surround speaker is to give the
listener a sense of immersion in the musical event.  This is done by reserving
the rear channels for audience sounds, in the case of a live recording, or
perhaps by reproducing the reverberant acoustics of the recording
environment itself.  Other engineer/producers prefer using five identical
full-range speakers and mixing primary instruments and vocals into the
surround channels.

So, our basic recommendation for mixing an audio-only six channel recording
is to intentionally limit the frequency response of the rear speakers using a
graphic equalizer or high-pass (100 Hz rolloff)/low pass (12 kHz rolloff) filter
on your mixer.  This will help you get a rough idea of what a home system
playback will sound like.

This arrangement will also allow your mix to sound best over a well set up
car audio system.  This is because professional installers have learned that a
mobile system performs best when they concentrate on producing a
soundstage across the front of the vehicle.  They do this by placing high
quality drivers in the front of the vehicle which produce frequencies from the