I.C.E. Install- Wire routing

[HustleRussell]

Right, I have finished installing the head unit and now I have to install amplifiers and sub woofer. First I must run the following wires from the HU to the boot area;
-2x RCA
-Switch live for amplifiers
-2x speaker wires from amps to front components
no main power or earth wires to run because the car is a BMW with the battery under the rear seat.

I'm pretty sure most of the car's wiring runs along the nearside sill, so where should I run the new wires I need? I'm guessing avoid nearside sill and use offside or go under the center console? Can I run the 5 wires I need in one bunch or do they need to be seperated from one another?

[Ozzie Osmond]

No risk of "mains hum" with 12v DC in a car so you can have them all together. The real question is whether you're using good quality shielded cable between HU and boot amp.

[liner33]

I usually run them under the centre console if possible

[Andy_sx]

Personally I would run all cables down the middle, as there will be a power supply running from back to front, and then split left and right for the components

[Mr Happy]

Ozzie Osmond said:

No risk of "mains hum" with 12v DC in a car so you can have them all together. The real question is whether you're using good quality shielded cable between HU and boot amp.

Not quite correct, a high amperage DC supply in close proximity can still introduce interference into RCA cables etc. Admittedly, shielded cable will go some way to combating it, but shielded RCA and speaker cable is usually more expensive than it's regular, off the shelf unshielded cousin.

The general consensus for audio wiring is power down one side, signal down the other. The amp remote is a very low amperage wire (less than 0.7a usually) and can safely be run alongside signal cabling. Some RCA cables actually provide provision for the amp remote in their cable jacket.

If space is an issue, then RCA up the middle, signal down one side, power up the other would suffice.

ETA - as this is a BMW, try to keep your RCA and speaker cables away from the front-to-back power cable for the car. If that runs up the drivers side, then run your signal cables up the passenger side.

Edited by Mr Happy on Friday 15th February 12:01

[Dave200]

Mr Happy said:

Ozzie Osmond said:

No risk of "mains hum" with 12v DC in a car so you can have them all together. The real question is whether you're using good quality shielded cable between HU and boot amp.

Not quite correct, a high amperage DC supply in close proximity can still introduce interference into RCA cables etc. Admittedly, shielded cable will go some way to combating it, but shielded RCA and speaker cable is usually more expensive than it's regular, off the shelf unshielded cousin.

The general consensus for audio wiring is power down one side, signal down the other. The amp remote is a very low amperage wire (less than 0.7a usually) and can safely be run alongside signal cabling. Some RCA cables actually provide provision for the amp remote in their cable jacket.

If space is an issue, then RCA up the middle, signal down one side, power up the other would suffice.

ETA - as this is a BMW, try to keep your RCA and speaker cables away from the front-to-back power cable for the car. If that runs up the drivers side, then run your signal cables up the passenger side.

Edited by Mr Happy on Friday 15th February 12:01

Having previously disagreed, and ended up disassembling my Golf a second time, I would wholeheartedly concur.

[HustleRussell]

RCAs are these Audison ones which looked decent for the price;

http://www.caraudiodirect.co.uk/con-ft2-550-connec...

Sounds like since the main wiring loom of the car goes down the nearside, I can bunch all my cabling together and route it under the center console or down the offside.
Thanks for the advice.

[HustleRussell]

Actually the car's main battery earth runs under the center console, can that induce interference into the system if I run my cables alongside it?

[HustleRussell]

Sorry to bump my own thread but I could really do with an answer to this last question

HustleRussell said:

Actually the car's main battery earth runs under the center console, can that induce interference into the system if I run my cables alongside it?

[Mr Happy]

HustleRussell said:

Sorry to bump my own thread but I could really do with an answer to this last question

HustleRussell said:

Actually the car's main battery earth runs under the center console, can that induce interference into the system if I run my cables alongside it?

I'd try to keep signal cabling as far away from any power cabling as possible (incl earth cable).

If I was in your situation, I'd bundle it and whack it up the offside. Just be careful if you have to cross any power cabling.

[DrDeAtH]

Run it up the side of the tunnel. It will be a shorter run, and far enough away from the main earth. Also you will avoid paralleling the main loom along the sill
Run the amp switched live separate from the RCA lead also (dont use the RCA lead with it integrated) running alongside will be fine.

Make sure also that all connections to the main earth point are CLEAN and TIGHT, otherwise you will introduce hum.