JBL owner manual Tuning BTX250, Controls and Functions, Adjustment Sequence

Tuning - Control and Functions - Adjustment J B L BASSTU B E BTX250

TUNING BTX250

BTX250 provides several controls that simplify sonic integration with virtually any vehicle’s unique acoustic proper- ties. Please read the following section carefully to familiarize yourself with the function of each control.

Figure 6. Locations of controls.

Phase Control: The phase control is a switch located on the panel with the electrical connections (see Fig. 6). This switch will reverse the phase of BTX250’s output with respect to its input. When installing BTX250 with an existing factory or aftermarket system, depending on BTX250’s location in the vehicle and the distance between it and the other speakers in the car, reversing the phase (by moving the phase switch) may produce a discern- able increase or decrease in the amount of upper bass reproduced. Although the position that yields the

most upper bass is technically correct, you may choose the position that better suits your taste.

CONTROLS and FUNCTIONS

Gain Control: This control will adjust the input sensitivity of BTX250. Use this control to adjust the relative volume (loudness) of BTX250 with respect to the other speakers in the vehicle.

Crossover: The crossover control adjusts the amount of high-frequency information present in BTX250’s output.

Bass Boost: BTX250’s interaction with the acoustics of your vehicle may produce a peak or dip in BTX250’s response. For the vast majority of vehicles, these peaks or dips occur at about 40-50Hz — around the frequen- cy of a low bass guitar note. Use this control to correct that peak or dip. Adjustment between 0dB and +6dB is possible. Although response without any sharp peaks or dips is technically correct, you may choose the position that best suits your taste.

Power LED: The power LED will glow green to indicate that BTX250 is oper- ational.

ADJUSTMENT SEQUENCE

1.Start with gain control set to mini- mum and the crossover control and bass control rotated midway, to 12 o’clock.

2.Choose program material with sub- stantial bass content and turn the vol- ume control on your head unit to three- quarters of its total output (approxi- mately 3 o’clock on rotary controls).

3.Adjust the gain control clockwise until you start to hear some distortion coming out from the BTX250.

Then slightly decrease the gain control counter clockwise.

4.Listen to your system, making a mental note of the amount of upper bass being reproduced.

5.Switch the phase control to 180° and listen again for upper bass con- tent. There may be more upper bass, less upper bass, or no change at all. The position that provides the most upper bass is correct, but choose either setting according to your taste.

6.Adjust the crossover control clock- wise or counterclockwise until you hear only low-frequency information. For example, you should NOT hear any vocals coming from BTX250 when seated in the normal listening position.

7.Adjust the bass-boost control clock- wise or counterclockwise to suit your taste.

Note: In most cases, the above steps will provide satisfactory tuning. However, the actual process may require several readjustments of each control, since the settings will interact with each other. If necessary, consult your authorized JBL car audio dealer for help in tuning your system.

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