Mackie HRS150 POWER LED, SUB BYPASSED LED, SUBSONIC FILTER, FILTER BYPASS, FILTER SELECT, LFE GAIN, INPUT SENSITIVITY, THX = FLAT, THX = FULL RANGE, THX = 0 dB, THX = NORMAL

REAR PANEL DESCRIPTION

This is where you connect your signal inputs and outputs to the subwoofer, and make adjustments 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 operating normally.

If there is no signal present for several min- utes, the HRS150 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 HRS150 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 15 Hz. This eliminates unwanted low-frequency energy so that all the power from the HRS150 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.

FILTER SELECT

FILTER SELECT	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 110 Hz elliptical low-pass filter for the subwoofer.

Use the elliptical filter when mixing for surround 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 = 0 dB

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 channel 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 decoding the LFE channel.

For Playback: Push this switch in to add 10 dB of gain to the subwoofer signal. This is useful for home theater applications where the LFE channel requires additional gain to balance with the other channels in the surround sound system.

INPUT SENSITIVITY

INPUT SENSITIVITY

OFF NORMAL

THX = NORMAL

The HRS150 expects a line-level signal at its input connectors.

•The sensitivity is 89 dB SPL at one meter with a 100 mV (–17.8 dBu) input signal, with the

INPUT SENSITIVITY control set to its NOR- MAL position (in other words, wide open).

•The HRS150 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.

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