JBL Px300.4 Installation and Setup, Setting Output Mode, Setting Input Sensitivity, Setting DBO

INSTALLATION AND SETUP

SETTING THE

OUTPUT MODE

Setting an output mode depends on your choice of system configuration and the nominal impedace of your speaker system. JBL Power Series BPx amplifiers provide rated power into any impedance between 1 and 4 ohms. The BPx500.1, BPx1100.1 and BPx2200.1 amplifiers can be configured to provide high voltage to loads of 2 ohms or greater, or high current for loads below 2 ohms.

Using the Bridge Mode

If your speaker system has a nominal impedance of 2 ohms or greater, bridge the amplifier’s two channels to drive the speaker(s). On BPx models, set the OUTPUT MODE switch to 2CH/BR (see Figure 2 on page 3).

Using the Parallel Mode

(BPx Models Only)

If the nominal speaker-system impedance is less than 2 ohms, connect the two amplifier channels in parallel to drive the speaker(s), as shown in Figure 3 on page 3.

On BPx models, set the OUTPUT MODE switch to PARALLEL.

NOTE: If the nominal impedance of your subwoofer system is close to 2 ohms, try both series and parallel to determine which mode provides the highest volume. Use the I/E OPT LED according to “Setting Input Sensitivity” on the right.

Using the 2-Channel Mode

With any Power Series amplifier, you can also drive two woofers separately by connecting the speakers in the

2-channel mode (see Figure 1 on page

3). In this mode, the minimum nominal impedance is 2 ohms. On BPx models, set the OUTPUT MODE switch to 2CH/BR.

SETTING THE CROSSOVER(S) IMPORTANT: If you plan to use the Px300.4 or Px600.2 to drive full-range speakers, set the X-OVER MODE switch(es) to FLAT and skip to the next section, “Setting Input Sensitivity.”

1.Initially set the X-OVER FREQ control(s) midway. Later, when listening to music (in the next section), adjust them for least- perceived distortion from midrange and high-frequency speakers, while allowing them to reproduce as much bass as possible.

2.Depending on your system plan, set the X-OVER MODE switch(es) to LP (low-pass), HP (high-pass), or FLAT.

3.For HP filters, set the X-OVER SLOPE switch(es) to 24dB to limit bass and provide increased system volume with less distortion.

For LP filters, use 12dB or 24dB according to taste. However, using a 24dB slope will make bass less directional since midrange frequencies are being filtered from the woofer’s response. When choosing a low-pass filter frequency for your subwoofers, choose the highest frequency that will remove vocal information from the sound of the subwoofer.

SETTING INPUT

SENSITIVITY

NOTE: For BPx models, you can use the supplied REMOTE LEVEL CONTROL instead of the amplifier’s INPUT LEVEL control to set input sensitivity. Connect the remote module’s attached cable to the REMOTE LEVEL CONTROL (RJ-11) jack on the amplifier’s input panel.

1.Initially, turn the INPUT LEVEL control(s) to the minimum (counterclockwise) position(s).

2.Reconnect the (–) negative lead to your vehicle’s battery. Apply power to the audio system and play a dynamic music track from CD or tape.

NOTE: After the source unit is on, blue LEDs (on the top panel) will illuminate, indicating the amplifier is on. If not, check the wiring, especially the remote connection from the source unit. Also refer to “Troubleshooting” on the next page.

3.On the source unit, increase the volume control to maximum position. Slowly increase the INPUT LEVEL control(s) (clockwise) towards three o’ clock and observe the I-E/OPT LED (on the amplifier top). At the ideal set- ting, it should flash on musical peaks, signifying maximum voltage is being delivered in the 2-channel or bridge modes, or maximum current is being delivered in the parallel mode. If the I-E/OPT LED is on steadily, the amplifier is being overdriven. Turn the INPUT LEVEL control(s) back slightly until the I-E/OPT LED flashes on musical peaks.

SETTING DBO

(ALL MODELS EXCEPT PX600.2) Dynamic Bass Optimizer™ (DBO) is a new approach to enhancing low- frequency reproduction in a vehicle. Conventional bass boost controls add bass at a fixed frequency and cause the amplifier to consume considerable power. DBO conserves valuable power at the lowest frequencies and allows you to adjust the level and “character” of the bass sound, instead of just the amount of boom.

Since a subwoofer in a vented box is given to overexcursion below the tuned frequency, set the HP FREQ control 10Hz below the box’s resonant (tuned) frequency (e.g., 30Hz for a vented box tuned to 40Hz). Power typically wasted in this region will now be conserved and be available for frequencies the enclosure will reproduce. Use the BOOST Installation and setup control to boost the bass at the set frequency by as much as 12dB, as shown in Figure 8.

DBO HP FREQ Control			HP FREQ
	(adjusts cut-off
dB		frequency)	20Hz	100Hz
0
-3
-6
-9
-12
	20	80	Freq. (Hz)
DBO BOOST Control			BOOST
(adjusts boost amount
dB	at cut-off frequency)		MIN	MAX
12
6
0
-6
-12
	20	80	Freq. (Hz)

Figure 8. Frequency response curves show typical DBO control ranges for selected JBL Power Series amplifiers.

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