Coustic 240SE Final System Check, Input Sensitivity Control, Crossover Frequency Adjustment

FINAL SYSTEM CHECK

INPUT SENSITIVITY ADJUSTMENT

The Input Sensitivity Control is located on the Front Panel. The objective of input sensitivity adjustment is to match the output of the source unit with the input of the amplifier. The output voltage of individual source units can vary. For example, some radios have an output of 200 mV and others have 5 Volts or more. To cater to these variations, the SE amplifier has an adjustable input sensitivity level that ranges from 100 mV to 5 volts.

Adjusting this control requires some experimenting. Basically, you want all the gain at the begin- ning of the system, NOT at the end (amplifier). Turn your headunit UP and keep your amplifier gains at the minimum possible setting (counter-clockwise). This will give you the best sound and lowest signal to noise ratio.

Besides better sonic reproduction, proper input sensitivity also helps to prolong the reliability span of your amplifier by eliminating excessive internal temperature generated by incompatible source unit output and amplifier input.

Note : Turning the input gain UP does NOT indicate MORE power. Just MORE noise. The input gain control IS NOT a power control. REMEMBER that the input gain control has nothing to do with the power output of the amplifier.

NPUT SENSMODE

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MIN	MAX HPF OFF LPF
5 volts	30
	.1 volt

Figure 10: Input Sensitivity Control

1.Turn the Input Sensitivity Control all the way down (counter clockwise).

2.Set the volume control of the source unit to approximately 2/3 of its maximum output.

3.Turn the balance control of the source unit to its center position.

4.Leave the tone (bass/treble) controls at their usual position.

5.Play a CD or tape track with great dynamic range.

6.Use the Bass Boost Control to enhance the bass performance (if desired).

7.To locate the optimum input sensitivity setting, ask the person assisting you to turn the Input Sensitivity Control clockwise until audio distortion starts to develop. Turn the sensitivity control backwards slightly to minimize the distortion.

8.If you constantly switch between CD/tape and radio, you will need further adjustment since radio output level differs from that of CD or tape. In this case, you need to locate a balanced sensitivity setting which is best for both the output level of radio and that of CD or tape.

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CROSSOVER SELECTION

The amplifier has built-in high-pass/low-pass filters that can be defeated by sliding the switch to the OFF position.

1.When the high-pass is selected, the amplifier will be devoted to mid/tweeters.

2.When the low-pass is selected, the amplifier will be used to drive woofers/subwoofers. With this setting, the optional RS can directly control the amplifier playback level.

3.When the filter is switched off, the amplifier is used as a full range amplifier.

CROSSOVER FREQUENCY SELECTION

Both the high-pass and the low-pass section offer continuously adjustable crossover frequencies between 30 and 300 Hz. Adjust the setting according to your speaker component specification or to your particular preference.

100Hz Low-pass selecte

MODE	FREQ		BOOST
60		180
HPF OFF LPF 30		300	0

Figure 11: Crossover Frequency Adjustment

BASS BOOST CONTROL (BOOST)

Select a boost level between 0 dB and +18 dB to enhance the bass performance for your sound system. BASS BOOST is NOT free! Every 3dB of boost costs you twice as much in power. Make sure to set the final gains ……after setting the Bass Boost to work best with your sub-

woofer/enclosure combination. More is NOT always better!

SETTING UP USING RS (Remote subwoofer control)

If you are using the RS control, make sure to take this into account during set-up procedures of the subwoofer amplifier. You should set the system up with the RS plugged in, and with the level knob turned all the way down (counter-clockwise).

NOTE: the RS ONLY works when you’ve selected the

LPF (low-pass) crossover configuration.

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