Studio Technologies AN-2 - Manual (Page 3)

AN-2 User Guide Issue 3
Studio Technologies, Inc. Page 5
Introduction
The Studio Technologies AN-2 Stereo
Simulator has numerous applications within
recording, live performance, film and broad-
cast operations because of its ability to
create a simulated stereo signal from a
monophonic source. The AN-2 is also
capable of a number of audio effects cen-
tering on its ability to simulate stereo. The
stereo signal produced by the AN-2 is
completely mono compatible, so that it can
be remixed back to mono without the seri-
ous signal degradation often encountered
when remixing simulated stereo produced
by other equipment such as delay lines and
harmonizers. In addition, the AN-2 is
equipped with a proprietary circuit that
randomizes the non-reclusive filtering pro-
cess, thereby avoiding the harmonic harsh-
ness that often results from stereo
simulation with delay lines.
Operational Description
To understand the operation of the AN-2,
it is useful to have a basic understanding
of the way stereo recording techniques can
fool the brain into believing it is hearing a
number of sound sources.
When two or more microphones are used
to record music, two effects are noticed
when the recording is played back over
two speakers. They are:
• Directional effects: These are due to
differences in arrival times at the ears and
the intensity differences of the various
frequencies that make up the music.
• Spaciousness imparted to the sound:
The sound is perceived as originating
from an area that is wider than the room
in which the listener is sitting. This
spaciousness is caused by the interaction
of the sounds that reach the microphones
directly and those sounds that reach the
microphones after being reflected from
the surfaces of the recording studio.
The degree of spaciousness of the re-
corded music coming from the two
speakers is dependent on the amount of
coherence (sameness or consistency)
between the signals fed to the speakers.
If the two channels are perfectly coherent
(the same signal fed to both speakers), the
sound heard is monaural and the source
of the sound seems to be midway between
the two speakers. As the signal fed to one
speaker begins to vary from the signal fed
to the other, the channels become incoher-
ent and the spaciousness of the sound
increases. This effect is known as “imag-
ing,” and results in the impression that each
instrument or voice is coming from a differ-
ent point in space. The definition and clarity
of the sound sources seems to increase as
the imaging increases, up until the point
where the two channels become completely
incoherent, or different. At this point, the
stereo image collapses and there is no
spacial effect at all. What is heard, rather,
are two mono channels.
The AN-2 is designed to allow you to vary
the degree of coherence of the sound (and
the resultant amount of imaging) using the
depth and width controls, creating a simu-
lated stereo signal from a monophonic
source. The two output signals of the AN-2
can be recombined, restoring mono.