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 4 or 5 dots from minimum.
Low-pass crossover- 40 to 120Hz
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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 & resulting cancellation between the subwoofer and your main speakers/amplifier. To adjust, 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.
Subsonic- 20Hz/35Hz
This adjustment alters the low frequency limit of the subwoofer. In certain movie theater installations which suggest that the extreme low bass be limited, move the switch position to 35Hz and the response will be attenuated below this frequency.
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Protection circuitry
Your new subwoofer is equipped with special protection circuitry to provide maximum performance with greatest reliability.
The unit is protected against:
1)Overdriving the speaker or amplifier.
2)Overheating the amplifier.
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. If this should happen, you should reduce the volume setting or shut the unit off until normal operating conditions return. You may also want to plug the unit into a different wall outlet, as dropping power line voltage will be most noticeable under strenuous conditions.
Distortion in loudspeakers
Nonlinear distortion is a problem which plagues all speakers. This particular type of distortion is a common problem in subwoofers, which must move large amounts of air to produce adequate levels of deep bass. Nonlinear distortion is defined as any form of distortion that moves energy from one portion of the audio frequency spectrum to another. When a single tone is applied to a nonlinear system, the result is harmonic distortion. In which some of the energy leaves the system at multiples of the original frequency. When multiple tones are applied, intermodulation tones are produced, usually as simple combinations of the input frequencies. Generally, 3% distortion is considered a reasonable amount for speakers. This means that 3% of the total energy leaving the speaker is at frequencies other than the intended input signal.
Most subwoofers on the market today however, produce much more than 3% distortion at common listening levels. Many models we have tested produce greater than 20% distortion @ 20Hz when driven to 100dB. This is a typical output level obtained in many
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