MB QUART RAB 1450: GENERAL INSTALLATION NOTES System design

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GENERAL INSTALLATION NOTES

System design

The success of any car stereo system relies on several factors, such as the system design, execution of the installation, and system setup.

This section is intended to assist the installer by offering several tips and hints about good installation practice. Please remember that any

system is only as good as its weakest link.

Determine the system format, e.g., single amplifier, active, front/rear and so on. Then choose the amplifier power points according to personal

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taste. Please remember that higher power systems are not necessarily useful purely for high sound pressure levels, but also to establish a headroom

capability, to reproduce musical peaks cleanly without distortion. Lower power amplifiers will clip earlier than their more powerful cousins, and

cause loudspeaker failure when overdriven, due to the harmonics generated by a clipped signal, thus overheating voice coils.

Choose loudspeaker and amplifier mounting locations. Loudspeaker location is always a matter of compromise between space and sound stage

imaging. Amplifiers should be mounted with the fins running vertically for best convection cooling, to minimize overheating.

Purchase the best quality RCA cables you can afford, for reliability and less engine noise interference in the audio system.

Installation

General:

Mount the amplifier/s in the chosen location.

Run the wiring so that RCA cables are at least 18“ away from power and speaker cables. Keep RCA cables away from electrical devices in the vehicle

that can cause electrical noise, such as fuel pumps.

Power and ground connections:

Use a sufficient gauge power cable, at least #8 per amplifier. In a multi amplifier system, it is advisable to mount a large enough fuse right at the

battery, and run a master +12 volt power cable to a fused distribution block near the amplifiers. It is then a simple matter to connect the +12 volt

terminal of each amplifier to the distribution block.

Ground each amplifier with as short a ground lead, again at least #8 gauge, directly to the vehicle chassis. Use a ground distribution block, if you

wish, but it is extremely important to keep the main ground lead from this distribution block to the chassis as short as possible, not more than 12“.

The ground connection integrity to the chassis is very important, and the best way to achieve a good, solid electrical and mechanical contact is to

use a large round crimp lug, crimped and soldered to the ground cable. The next step is to scrape the paint off the vehicle chassis, slightly larger

than the ground lug, at the connection point. Drill a clearance hole in the chassis, the same size as the lug hole, and use a bolt, spring washer and

nut to securely fasten the ground lug. Use petroleum jelly to coat the bolt/lug connection, to prevent oxidization with time.

TIP: Use the same approach when installing head units, equalizers or any audio equipment for that matter - run short individual grounds from each

piece directly to the vehicle chassis, to minimize ground loops and system noise.

All power, ground and speaker connections should be crimped and soldered for reliability. Make sure that none of the cable insulation can chafe

against exposed metal in the vehicle, causing short circuits to the chassis.

Safe connection sequence:

After all cables are run, connect speaker wires to the speakers and amplifiers, then run and plug in RCA cables. Next, connect all power grounds

and remote turn on leads. Now connect all +12 volt cables to the amplifier/s and distribution blocks and fuse holders. Finally, connect the main

+12 volt cable to the battery, with the main fuse removed, and we are almost ready to power up the system.

Power up the system:

The following procedure may seem like overkill, but there is nothing more frustrating than turning on a system for the first time, and it does not

work properly immediately.

First, make sure the head unit is off, and turn all level controls to minimum (anticlockwise), including the head unit volume control. Set all equa

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lizers to 0 dB (no boost), and all crossover frequency controls at approximate frequencies, as recommended by the loudspeaker manufacturer. Set

all input selector and crossover switches as required for the application.

Remove all amplifier fuses, and insert the main fuse at the battery. If the fuse does not blow, you can insert the fuse in one of the amplifiers, and

we are ready to turn on the system.

Turn the head unit on, insert a CD, or select a radio station, and increase the head unit volume control. If the system sounds fine, turn off the head

unit, and install fuses in the remaining amplifiers, one by one, till the complete system is powered up and functioning properly.