Coustic & 480QE, 320QE Final System Check, Input Sensitivity Adjustment, Crossover Selection

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 QE 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

		FRONT				REAR
R	MODE			FREQ	MODE			FREQ
			60				60
	HPF OFF LPF180				HPF OFF LPF180
		300	30			300	30
	SENS		BOOST		SENS			BOOST
	MIN	MAX	0		MIN	MAX	0
	5 volts		+18	5 volts			+18
		.1 volt				.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 for both front and rear channels 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.

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 subwoofer/enclosure combination. More is NOT always better!

Front:High-Pass	Rear:Low-Pass
Frequency adjustment	Frequency adjustment

Front:High-Pass Selected				Rear:Low-Pass Selected
UTS		FRONT			REAR
REAR	MODE		FREQ 180	MODE		FREQ180
		60			60
	HPF OFF LPF			HPF OFF LPF
		30	300		30	300	REMOTE
	SENS		BOOST	SENS		BOOST	SUB LEVEL

Figure 11: Crossover Frequency Adjustment

SETTING UP 480QE 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 in the "rear channel", and ONLY when you’ve selected the LPF (low- pass) crossover configuration.

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