Velodyne SubContractor Series - Manual (Page 16)

www.velodyne.com 10 - SC-1250 Amplifier User’s Manual
you should set the crossover frequency to obtain a smooth and seamless transition from the subwoofer(s) 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 100-120 Hz) 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 80
Hz. The SC-1250 crossover has a default of 80 Hz.
Most receivers and processors provide an option to characterize main speakers as “large” or “small.” This
affects the crossover point. We recommend in most cases setting the main speakers to “small,” despite their
size and frequency response characteristics. This is because the powerful 1250 watt SC-1250 combined with
the SC subwoofer(s) you have acquired are more than likely more suited to low bass reproduction than your
amp and main speaker combination. With the burden of low frequency reproduction relieved, your amplifier and
main speaker combination will enjoy better performance and about 50% more available headroom, enabling
them to more accurately reproduce the rest of the frequency spectrum.
Disabling the Low-Pass Crossover (Subwoofer Direct)
If your receiver/processor provides a crossover to the subwoofer(s), you may want to bypass the SC-1250’s
low-pass crossover. To do this, depress BOTH the Crossover UP and Crossover DOWN buttons simultaneously.
The numeric led will show indicating that the low-pass crossover has been defeated. To reactivate the low-
pass crossover, simply push the crossover UP or crossover doWn buttons.
A Word About Your Receiver’s Crossover and the SC-1250 Crossover
Your Velodyne SC-1250 amplifier 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 performs this same function and are designed to be used with a powered subwoofer.
In these installations, you may want to bypass the crossover in either the processor or the velodyne SC-1250
as described above. However, in some cases you may want to use BOTH crossovers. If you choose to do this
you should stagger the frequencies, (i.e., 120 Hz subwoofer, 80 Hz processor) for best results.
note: If not using an external crossover, you should use the built-in crossover for optimal performance. When
using a single RCA sub out from the processor, it does not matter which line level input (L/R) is used.
A Word About Interconnect Cables
When installing your velodyne SC-1250 using the line-level connections, you should always use high quality
shielded interconnect cables. It is recommended that you keep the length of cable as short as possible to avoid
any potential external interference problems.
When connecting the SC-1250 to your subwoofer(s), use a quality speaker cable that is at least 14-gauge. Be
very careful to avoid any loose or frayed strands that could result in a short, causing a dangerous condition and
possible damage to your unit. Cables of extremely large size are typically not required. Extremely large gauge
wire may not properly fit in the binding posts, resulting in a poor connection and possible short circuits.