Subwoofer Direct switch- In/Out
This switch allows the electronic crossover circuitry to be removed from the signal path. This is required in certain installations which route the signal through external processors with a crossover circuit of their own, such as the new digital units. Simply move the switch to OUT to disengage the built in crossover. For all other installations which do not have a separate electronic crossover we recommend you leave the internal crossover IN to provide optimum performance.
Auto turn on switch- Auto/On
The auto turn on switch allows the user to utilize or bypass the automatic signal sensing circuitry. When set in the AUTO mode with main power ON, the subwoofer will turn itself on when an input signal is present. If no signal is present, after several minutes the unit will shut itself off. When set in the ON mode, the auto turn on/off function is bypassed and the unit will be on whenever the main power switch is on.
Power switch
The master power switch is located on the right half of the unit. This rocker style switch is the main on/off for the unit. This switch should be set to position 1 (up) for on, and 0 (down) for off. If the unit is to be left unused for an extended period of time, the master power switch should be turned off.
Line-level connection
Figure 1 shows connection to a pre-amplifier's main outputs and returning them to your amplifier inputs.
When installed in this fashion, your satellite speakers will be crossed over at 85Hz which removes the lower bass from your amplifier and speakers, enabling them to do a better job reproducing high frequencies. By utilizing this method, you will have a
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), the unit may shut down momentarily. The green power led may also blink rapidly. This indicates operation of the thermal 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 systems, particularly home theater systems. Even at 1 watt, many conventional units produce several percent distortion. Secondly, the odd order, higher harmonics are much more offensive to the human ear than the closer 2nd harmonic.
An interesting result of this reduced distortion is that some of the bass, when played over an extremely accurate subwoofer system, seems to actually be missing. The truth, however, is that the "missing" bass was never there to begin with! Distortion products of conventional
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