Velodyne SPL-1200 Series II - Manual (Page 8)

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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 pre-amp,
signal processor, line-level crossover, or receiver with pre-amp level
outputs. The SPEAKER LEVEL jacks connect directly to the speaker
outputs of any amplifier, integrated amplifier, or receiver. Your amplifier
section will notice no additional loading effects when you use these inputs
due to their very high impedance.
Important!!!
Do not use both LINE LEVEL and SPEAKER LEVEL connections
simultaneously!
Volume control
This control allows you to balance the output from the subwoofer to the
main speakers/amplifier in your system. 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 120Hz
All inputs sum the left and right channels together, with the resulting signal
passing through an adjustable low-pass crossover before being amplified.
The crossover control allows you to adjust the upper limit of the
subwoofer's frequency response from 40 to 120Hz. The subwoofer's
response will begin rolling off above the 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 limited low frequency output, you may
wish to choose a higher frequency (such as 100-120Hz) than you would
with larger speakers which have greater low frequency output. With larger
speakers, you might start with this control set lower, such as 80Hz.
A bypass switch is also provided if you wish to use an external crossover.
If you are not using an external crossover, we recommend that you use
the one provided within the unit for optimum performance!
Phase adjustment - 0°/180°
This control allows you the "reverse" the phase of the subwoofer's output
signal 180° to correct for any possible mismatch and resulting cancellation
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To bypass the subwoofer's internal crossover when the unit is being fed
a low pass signal from another crossover, simply locate the switch marked
INTERNAL X-OVER/SUBWOOFER DIRECT on the rear panel of the
subwoofer and set to the SUBWOOFER DIRECT position. This will
eliminate the internal crossover from the signal path.
Speaker-level Connection
Figure 3 shows an easy way to connect your Velodyne subwoofer directly
to your receiver or integrated amplifier, if it lacks line-level outputs. You
may also connect your satellites directly to your receiver or amplifier along
with the subwoofer. Your receiver or amplifier will not notice the additional
load of the suboofer due to the high input impedance.
Caution!!! To avoid damage to your main amplifier, be sure to maintain
correct polarity when making all connections. Red (positive) to red, and
black (negative) to black. Be sure that all connections are tight, and that
there are no loose strands or frayed wires.
Interconnect Cables
When installing your new Velodyne subwoofer using the line level
connections, you should always use shielded phono cables. There are
many decent cables available today, most any of which will work perfectly
well. We do recommend that you keep the length of cable as short as
possible to avoid any potential noise problems.
When using speaker level connections, use a decent quality speaker cable
that mates well with the connectors. Be very careful to avoid any loose
The Velodyne subwoofer is designed to operate using the full range audio
signal for input when using the built-in crossover. Many home theater
processors/receivers (Dolby Digital, DTS, THX) have a "subwoofer out"
jack that is internally filtered and designed to be used with a powered
subwoofer. In these installations, you may bypass the internal crossover
in either the processor or the Velodyne subwoofer. In some installations,
it may be beneficial to have a steeper ultimate crossover slope. To do this,
you can use both your processor's crossover and the one internal to the
Velodyne sub. You should stagger the frequencies, (i.e., 120Hz sub, 80Hz
processor) for best results.
Subwoofer Outputs