User manual VELODYNE SPL-ULTRA DATASHEET

[. . . ] Read Instructions -- All safety and operating instructions should be read before the subwoofer is operated. Retain Instructions -- The safety and operating instructions should be retained for future reference. Heed Warnings -- All warnings on the subwoofer and in the operating instructions should be adhered to. Follow Instructions -- All operating and use instructions should be followed. [. . . ] Please observe the following instructions to insure safe and proper system operation. Note: Do not leave unit in direct sunlight or use in high humidity environments!!!To prevent fire or shock hazard, do not expose this equipment to rain or moisture. To avoid electrical shock, do not open speaker enclosure or amp chassis cover. Please observe all warnings on the equipment itself. There are no user serviceable parts inside. Please refer all service questions to your authorized Velodyne dealer. Prior to installationPlease unpack the system carefully. Use caution when lifting or moving to avoid injury. Remove all staples used to seal the carton as they can scratch the cabinet. Please save the carton and all packaging materials for future use. 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! [. . . ] 3) Excessive drop in power line voltage. The first type of protection circuitry which prevents overdriving of the speaker or amplifier operates constantly without being audible under most situations. In some extreme situations (sustained high output levels such as pro sound usage), the unit may shut down momentarily. This indicates operation of the thermal or undervoltage protection circuitry. [. . . ]