MTX Audio 4405 Adjusting the Gain, Typical Speaker Wiring Configurations, Troubleshooting

AMPLIFIERS

Adjusting the Gain

1.	Turn the gain controls on the amplifier all the way down.
2.	Turn up the volume control on the source unit to approx-
	imately 3/4 of maximum.
3.	Adjust the front channel gain control on the amplifier
	until audible distortion occurs.
4.	Adjust the front channel gain control down until audible

Typical Speaker

Wiring

Configurations

5-Channel Amplifier

Mono Amp and Bridged Stereo Amp

Impedance Requirements

— 2 ohm minimum for sub (mono) channel

—4 ohm bridge minimum for stereo channels

—2 ohm stereo minimum for stereo channels

Note: The information shown for bridged stereo channels is good for both the front and rear channels

Troubleshooting

Read this if you wanna be a do-it-yourselfer – or give us a call at 800-CALL MTX.

Problem	Cause	Solution
No LED indication	No +12V at remote connection	Supply +12V to terminal
	No +12V at Power connection	Supply +12V to terminal
	Insufficient ground connection	Verify ground connection

	distortion disappears.
5.	Follow steps 3-4 for rear channel and sub-channel gain
	settings.
6.	The amplifier is now calibrated to the source unit’s out-
	put. The rear and sub channels may be adjusted accord-
	ing to your personal taste.

4 ohm
4 ohm		4 ohm
	+ + - - +
	-	L L R R
	s
	u
	b

Two 4 ohm speakers for sub channel

One 4 ohm speaker for bridged stereo channel

OK

8ohm

8ohm

8 ohm	8 ohm
8 ohm	8 ohm

+ + - - + - L L R R s

u b

Four 8 ohm speakers for sub channel

Two 8 ohm speakers for bridged stereo channel

OK

4 ohm
4 ohm	4 ohm
4 ohm	4 ohm

+	- +
s	L L R R
u
b

Three or more 4 ohm speakers for sub channel

Two 4 ohm speakers for bridged stereo channel

NOT

OK

	Blown power fuse	Replace fuse
LED on, no output	Volume on head unit off	Increase volume on head unit
	Speaker connections not made	Make speaker connections
	Signal processing units off	Apply power to signal processor
	All speakers blown	Replace speakers
Output distorted	Head unit volume set too high	Lower head unit volume
	Amplifier gain set too high	Lower amplifier gain

Definitions of Common Terms

Balance reversed	Speakers wired L + R reversed	Wire speakers with correct orientation
	RCA inputs reversed	Reverse RCA inputs

The following list of terms with their definitions is offered as help in understanding the set-up and operation of your amplifier.

1.Crossover (xover) - an electrical filter with high-pass or low-pass characteristics that divides the frequency range into playable bands for certain speakers. Subwoofers, mid-bass, midrange and tweeters are all designed to play different frequencies and should do so to avoid damage. The xover point is where the playable frequencies cross from one speaker to the next at -3dB below reference level.

2.Full-range - refers to signals which cover the entire audio frequency span from 20Hz to 20kHz.

3.High-pass - simply put, this blocks lower frequencies which damage smaller speakers, and passes the higher frequencies for smaller speakers like the midrange and tweeter.

4.Low-pass - you got it, this is the inverse of a high-pass. It blocks higher frequencies and passes the playable lower frequencies to the larger speak- ers, like subwoofers.

5.Impedance - the resistance to the flow of current in an alternating current circuit (such as with music). Line level circuits are typically a high impedance of several thousand ohms, while speaker level circuits are usually a low impedance of a few ohms.

6.Line level - the type of signal produced at the outputs of tape decks, CD tuners, preamplifiers, etc., with a typical value of a volt or less in a high impedance circuit.

7.Speaker level - the type of output that is meant to drive speakers. These signals are sometimes called high level and are usually connected by two conductor speaker wires.

8.Signal - the signal of an audio system is what is heard from the speakers. These signals may be high pass, low pass or full-range.

We don’t have enough space for Electronics 101, so if you have a good, bad or amusing question, please call us TOLL FREE at 800-CALL MTX! (800-225-5689)

Some balance reversed	Some Speakers wired L + R	Wire speakers with correct orientation
	reversed
	Some RCA inputs reversed	Reverse appropriate RCA inputs
Bass is boomy	Thunder EQ too high	Lower setting
Bass is weak	Thunder EQ too low	Raise setting
	Speakers wired out	Wire with correct phase
	of phase
	Not using MTX woofers	Buy MTX woofers
Blowing fuses	Excessive output levels	Lower volume
	Amplifier defective	Return for service

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