JBL SDP-3 Installation & Technical Manual page 60

AC-3 Effects and Parameters
SDP-3 Digital Surround Processor/Controller
BASS ENHANCE derives stereo bass to provide low frequencies that
are noticeably less localizable and more spacious in the playback room.
Note that results will vary depending on room acoustics and the low
frequency capacity of the surround speakers.
CENTER DLY SAMPLES adjusts the time offset of the center channel.
The appropriate value is +0 unless you know that the center channel is
not properly timed, as well as the amount by which it is off.
CENTER LEVEL adjusts the output level from the center speaker.
CENTER MIX adjusts the level of the center channel applied to the two-
channel downmix. The appropriate value for film is 16. The appropriate
value for music is 11.
COMPRESSION enhances the intelligibility of Dolby Digital material at
low volume levels (-6dB or lower). When set to AUTO, this control
automatically limits peak signals and boosts low level signals. The
amount of compression increases proportionately as volume is de-
creased. This is quite useful when listening to Dolby Digital soundtracks
at low output levels. When set to ON, full compression is applied,
regardless of volume.
FRONT STEERING provides three basic settings which have been
developed specifically to optimize center channel signal strength for film
and music.
The FILM setting has excellent frontal image stability through the whole
room during dialog and vocals, while preserving the full width of the front
image in the spaces between dialog, and for music without vocals. The
front image during vocals is noticeably narrower than with the MUSIC
setting, but highly satisfactory nonetheless.
The MUSIC setting reproduces sound in all three front speakers when
a strongly centered, or mono signal is present. This is an excellent
choice for heavily centered pop music such as metal and sounds more
natural for broadcast material with a single announcer. OFF sets the
center channel level to 4.5dB less than the front left and right speakers,
and then leaves the level unchanged as the steering varies. This setting
is equivalent to conventional stereo with a slight center fill.
LFE MIX LEVEL allows separate level attenuation of the LFE channel,
which is ultimately mixed to the subwoofer output. As the bass from as
many as five other channels is added to the LFE, it can significantly raise
subwoofer output levels — and create the risk of damage to a system.
Careful adjustment of this parameter will allow you to achieve proper
tonal balance and reduce the risk of damage.
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