
www.velodyne.com SPL-800i User’s Manual - 3
INSTALLATION
Inputs
Your new subwoofer is equipped with speaker-level and line-level inputs. Use the LINE LEVEL jacks when
connecting your subwoofer to a preamp, signal processor, line-level crossover or receiver with pre-amp level
outputs.TheSPEAKERLEVELjacksconnectdirectlytothespeakeroutputsofanyamplier,integratedamplier
orreceiver.Yourampliersectionwillnoticenoadditionalloadingeectswhenyouusetheseinputsduetotheir
very high impedance.
Important!!! Do not use any of the LINE LEVEL, SPEAKER LEVEL, and MINI-JACK connections
simultaneously!
Volume Control
Thiscontrolallowsyoutobalancetheoutputfromthesubwoofertothemainspeakers/amplierinyoursystem.
This control should be set to achieve similar output level from both the main speakers and subwoofer when
listening to music. A good starting point for the volume control is 3 or 4 dots from minimum.
Low-pass Crossover - 40 to 120 Hz
All inputs sum the left and right channels together, with the resulting signal passing through an adjustable
low-passcrossoverbeforebeingamplied.Thecrossovercontrolallowsyoutoadjusttheupperlimitofthe
subwoofer’sfrequencyresponsefrom40to120Hz.Thesubwoofer’sresponsewillbeginrollingoabovethe
frequency you set this control to. You should set the crossover frequency to obtain a smooth and seamless
transition from the subwoofer to the main speakers in your system. If your main speakers are smaller units with
limitedlowfrequencyoutput,youmaywishtochooseahigherfrequency(suchas100-120Hz)thanyouwould
with larger speakers which have P greater low frequency output. With larger speakers, you might start with this
controlsetlower,suchas80Hz.
Abypass switch is also providedifyou wish to use an external crossover. Ifyou arenot using an external
crossover, we recommend that you use the one provided within the unit for optimum performance!
Phase Adjustment - 0°/180°
Thiscontrolallowsyouto“reverse”thephaseofthesubwoofer’soutputsignal180°tocorrectforanypossible
mismatchandresultingcancellationbetweenthesubwooferandyourmainspeakers/amplier.Toadjust,simply
listen to the system with music playing. Then move the switch from one position to the other and listen for a
change in low frequency output. The correct position will have a greater amount of apparent low frequency
output.
Crossover Switch - INTERNAL X-OVER/SUBWOOFER DIRECT
This switch allows the internal crossover circuitry to be removed from the signal path. This is required in certain
installationswhichroutethesignalthroughexternalprocessorswithacrossovercircuitoftheirown,suchasthe
new digital units. Simply move the switch to SUBWOOFER DIRECT to disengage the built-in crossover. For all
other installations which do not have a separate electronic crossover, we recommend you leave the switch set
to INTERNAL X-OVER to provide optimum performance.