S E T U P (continued)
MODEL 500 Controls
The MODEL 500 subwoofer amplifier has four variable controls to integrate its output to the subwoofer and for tailoring the subwoofer’s output to the room and to the primary speakers (also known as satellites). These controls are Level, Crossover Frequency, Phase, and subsonic filter. The control with the most audible effect is the Level control, followed by the Crossover Frequency, Phase control, and then Subsonic filter, which has the least audible effect.
The following legend shows graphically how each control affects the audio signal.
SPL (dB)
SPL | SPL |
(dB) | (dB) |
Frequency (Hz) | Frequency (Hz) |
LevelFrequency
SPL (dB)
Phase (Degrees) 20 35 | Frequency (Hz) |
Phase | Subsonic Filter |
Fine Tuning the Controls
We recommend the following method as a starting point for fine tuning the MODEL 500 subwoofer amplifier.
A)Level and Frequency
Begin with the amplifier’s Level control all the way down and the Frequency adjustment set to 120Hz. With the Frequency control in this position the woofer will output higher frequencies that will likely be duplicated by the satellite speakers.
Play some familiar music through the system (music with robust bass content) and increase the Level control until the bass passages sound robust or exaggerated. Then reduce the Frequency control to blend the subwoofer with your main system speakers. We have found that most speakers with 6” to 8” woofers blend well with the crossover set somewhere between 50Hz and 80Hz.
Readjust the Level and the Frequency controls (up or down) as necessary until the bass sounds full, extended, and natural. Use multiple musical pieces to test the system while fine tuning the controls. If it sounds like your subwoofer is always producing the same bass note with different recordings it is possible that the bass level is adjusted too high.
B)Phase
To adjust the Phase, use music with sustained bass notes. Rotate the Phase control back and forth across its range and listen for the localization of the bass to become more distinct and also slightly louder. While making this adjustment it can be helpful to temporarily adjust the Frequency control to 120Hz. This should provide some overlap of the satellite and subwoofer frequencies and help the ears (brain) to distinguish the two sound sources. Return the Frequency control back to its desired position after performing the phase adjustment.
C)Subsonic Filter
This control is used to protect the subwoofer from damage due to excessive excursion, reduce distortion, and also to preserve the amplifiers power in installations where the subwoofer is incapable of reproducing extremely deep bass passages. Ideally, the control should be set at or just below the system resonance. The factory default position is 35Hz. This will work well for most subwoofers 12” or less in diameter. For large subwoofers or where the system resonance is very low the control should be lowered below the 35 Hz position.
MODEL 500 AMPLIFIER O W N E R ’ S M A N U A L
