Coustic Comprehensive Guide to the Car Amplifier for Enhanced Audio Performance

	FRONT				REAR
MODE	60	FREQ	180	MODE	60	FREQ	180
HPF OFF LPF				HPF OFF LPF
SENS	30	BOOST	300	SENS	30	BOOST	300
MIN	MAX 0	+18		MIN	MAX 0	+18
5 volts	.1 volt		5 volts		.1 volt

Figure 14: 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 wide 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 counter clockwise 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.

BASS BOOST CONTROL (BOOST)

Select a boost level between 0dB and +18dB 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!

SETTING UP 481QE USING REMOTE SUBWOOFER GAIN CONTROL (R S)

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

NOTE: the R S ONLY works in the "rear channel", and ONLY when you’ve selected the LPF (low- pass) crossover configuration.

		COUSTIC.COM
TROUBLE-SHOOTING SECTION
SYMPTOM		PROBABLE CAUSE
1.	No power	Check connections to the amplifier's Ground, B+ & Remote
		terminals. Check connection at "+" terminal of the battery.
		Check the remote turn-on terminal. Ensure it receives power
		when the source is turned on (or when the switch is turned
		on). Refer to the Installation Section. Check the power line
		fuse: if fuse is blown, replace it; if fuse continues to blow,
		check the power wire and also the amplifier for a short. If the
		short is in the power wire, fix it; if the short is in the amplifier
		itself, see your Coustic dealer.
		Check the voltage at the amplifier, and the remote ON/OFF
		lead. The voltage should measure between 11 V - 15 V. If the
		measurement is beyond this range, have the source unit
		checked out by an authorized dealer.
2.	Power without sound with	Turn the amplifier off, and Check all input & output signal
	red power/protection	cables and connections. Check the speakers for short with
	indicator on	a VOM (volt meter) or by connecting them to another audio
		system. After making sure everything is normal, turn the
		amplifier on again.
3.	Power without sound with	The continuous red light of the power indicator signals a
	red power indicator on	high internal operating temperature, which results in the
		amplifier switching off temporarily; when the amplifier cools
		down to a safe level, the amp will automatically restart.
4.	No sound from one side	Check balance control.
		Check speaker connections.
		Check signal input connection.
5.	Very low sound from	Check your radio's fader control.
	both radio & tape	Check the amplifier's Input Sensitivity Level.
6.	Frequent automatic	This indicates that the amplifier is operating at a continually
	amplifier shut down	undesirable high internal temperature. High operating tem-
		perature caused by inadequate ventilation: Refer to the sub-
		section titled LOCATION for better amplifier location.
		High operating temperature caused by an excessively low

impedance load, say below 2 ohms stereo or 4 ohms bridged: Check for bad speakers and/or electronic crossover, proper passive crossover components; if all else fails, try rewiring the entire system.

High operating temperature can be caused by an incorrect input sensitivity level: refer to sub-section titled INPUT SENSI- TIVITY ADJUSTMENTS for correct setting.

7."Motorboating": The amplifier power indicator going off repeatedly when the audio system is on

8.Whining noise when engine is running with noise varying with the accelerator (noise level varies with source unit volume control)

Check the amplifier's connection to the battery. Check battery voltage. If low, recharge or replace battery. Check all ground connections.

Reroute power cable from battery to source unit directly, bypassing the battery terminal in the fuse box. Check power connections to be sure they areclean. Check ground connections to be sure the ground wire is in direct contact with the bare metal surface of the chassis (with that spot scraped clean of any paint, rust or grease).

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