MACKIE HRS120 - Manual (Page 8)

8
REAR PANEL DESCRIPTION
FILTER SELECT
FILTER SELECT
VARIABLE
110Hz ELLIPTICAL VARIABLE
110Hz ELLIPTICAL
This switch selects either the built-in 4th-order
24 dB/octave Linkwitz-Riley variable crossover
or the 7th-order 42 dB/octave 110Hz elliptical
low-pass filter for the subwoofer.
Use the elliptical filter when mixing for sur-
round sound applications with a LFE channel.
This steep filter emulates the “brick-wall” low-
pass filter used in AC-3 and DTS formats.
Use the variable crossover filter for normal
playback of stereo sound.
LFE GAIN
LFE GAIN 0dB
+ 10dB
THX = 0dB
For Surround Sound Mixing: Push this
switch in to add 10 dB of gain to the subwoofer
signal. This allows you to record the LFE chan-
nel at –10 dB relative to the other channels, as
specified by AC-3 encoding standards. Note
that 10 dB of gain is added back when decod-
ing the LFE channel.
For Playback: Push this switch in to add 10
dB of gain to the subwoofer signal. This is use-
ful for home theater applications where the
LFE channel requires additional gain to bal-
ance with the other channels in the surround
sound system.
INPUT SENSITIVITY
OFF NORMAL
INPUT SENSITIVITY
THX = NORMAL
The HRS120 expects a line-level signal at its
input connectors.
• The sensitivity is 89 dB SPL at one meter with
a 100mV (–17.8 dBu) input signal, with the
INPUT SENSITIVITY control set to its NOR-
MAL position (in other words, wide open).
• The HRS120 is designed to operate with a
nominal +4 dBu signal when the INPUT
SENSITIVITY control is in the NORMAL
position.
• Refer to the QUICK START section on
page 4 for the level-setting procedure.
This is where you connect your signal inputs
and outputs to the subwoofer, and make adjust-
ments to the crossover, filters, and input
sensitivity.
For THX applications, the
rear panel switches and
controls should be set to the
THX positions as indicated
on the rear panel.
POWER LED
The POWER LED lights when the power
switch is turned on and the subwoofer is oper-
ating normally.
If there is no signal present for several min-
utes, the HRS120 goes into bypass mode, the
POWER LED turns off, and the SUB BYPASSED
LED turns on. The instant a signal appears at
its input, the HRS120 comes to life and the
POWER LED lights again.
SUB BYPASSED LED
When the SUBWOOFER BYPASS circuit is
activated by either the auto-off circuit or the
FOOTSWITCH connection, the SUB BYPASSED
LED lights.
SUBSONIC FILTER
SUBSONIC FILTER
FLAT
15Hz
THX = FLAT
Push this switch in to engage the 3rd-order
18 dB/octave Butterworth subsonic filter,
which rolls off frequencies below 15Hz. This
eliminates unwanted low-frequency energy so
that all the power from the HRS120 amplifier is
dedicated to useful low frequencies.
FILTER BYPASS
FILTER BYPASS
FILTER IN
FULL RANGE
THX = FULL RANGE
This switch bypasses the built-in low-pass
filters (variable and elliptical). Push this switch
in when connecting an LFE or subwoofer
output signal from a mixer or preamp to the
LEFT(MONO) and/or RIGHT inputs, to avoid
“double-filtering” the low-frequency signal.
Note that the LEFT(MONO) and RIGHT
OUTputs are still high-pass filtered and affected
by the
CROSSOVER controls.