Iv. typical configurations, Subsonic filter (infrasonic filter) – JBL Professional MPC-XU User Manual
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IV. Typical configurations
Subsonic Filter (Infrasonic Filter)
Applications: Subsonic filters are commonly used in sound installations to filter out rumbles
and other inaudible or unwanted low frequency signals and to protect speaker tuned vented
speakers from damage due to excessive energy below the tuning frequency.
For a subsonic filter, determine the lowest useable frequency that the speaker can safely
handle and set the high-pass filter to that frequency. Typical subsonic filters are set at 50 Hz, 40
Hz, 30 Hz or 20 Hz.
Program settings:
1 Set Jx01 to bypass the low-pass filter (if not using) by placing jumper across pins 1 and 2.
2 Set Jx02 to enable the high-pass filter by placing jumper across pins 2 and 3.
3 No jumper on Jx03.
4 Insert proper resistor network in RNx04 socket.
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The table at left is a summary of the jumper
settings for the MPC-XU.
CD Horn Equalization (Boost)In addition to enabling the high-pass filter at Jx02, if you
opt for CD horn equalization you must place a jumper at Jx03 as well. The MPC-XU offers
two equalization curves for CD horn correction:
For +6 dB of boost at 20 kHz, place the jumper across pins 1 and 2 of Jx03.
For +10 dB of boost at 20 kHz, place the jumper across pins 2 and 3 of Jx03.
To bypass the CD Horn Equalization, do not place a jumper in one position or the other.