4
GETTING TO KNOW YOUR SP-18 ACTIVE 18” SUBWOOFER
PANEL CONTROLS
11) Level Control: Sets the volume of the subwoofer
12) Phase Switch: Sets the polarity of the SP-18.
13) Power Indicator: The Power indicator lights when the SP-18 amplifier
has been turned on and has power.
14) Protection: Red LED turns on when distortion is audible in the
amplifier output. This indicates that you should turn the amplifier
down.
15) Right & Left Inputs: These inputs are summed and sent to amplifier’s
Low Pass filter (120 Hz and below).
16) Right & Left Full-Range Outputs: Send stereo full-range signal
allowing daisy chaining of additional subwoofers. You do not need to
y-cable out of your mixer or audio device to get an additional full-
range signal.
17) Right & Left High-Pass Outputs: Send stereo high-pass signal (120
Hz and above) directly to active, full-range speakers or through a rack
mount amplifier to passive speakers.
18) External Speaker On/Off Switch: Turns Speakon NL-4 connector
(and external subwoofer) on and off. When only using the SP-18, turn
this switch off. When an external, non-powered subwoofer (SP-18S)
is connected, turn this switch on. NEVER turn switch on or off while
amplifier is turned all the way up.
19) External Speaker Output: The Speakon NL-4 connector connects
the amplifier to an external, non-powered subwoofer (SP-18S). Either
pins 1+ and 2+ can be used as the positive connection. Either pins 1-
or 2- can be used as the Negative Connection. External subwoofer
must be 8 Ohms
10) ON/OFF Switch: Turns the SP-18 amplifier on or off. The SP-18 will
only turn on when the amplifier detects an audio signal.
11) Fuse Holder: Houses a fast-resetting 12 amp fuse.
12) Power Cord Connector: For attachment of the included power cord.