Help Rewiring my Sound System

[Moya]

I'm a car audio noob and I want to rewire my sound system. I figure it can't be too ihard :p. A local (reputable :zip:) shop did the install for me (8 months ago), and although it's ok, It's got a few issues. For a start I get engine feedback in my speakers, which I'm told is because they've run the signal and power lines down the same side of the car. On top of this, my HU atm is doing weird shit where it random turns off/on while I'm driving.

So basically, because of this, and because of my somewhat arrogant attitude of needing to know how everything works, I want to redo the cabling. At the same time I'll hook up my rear speakers to my HU (current not connected (thanks again local installer!!!).

So this is a pretty newbie thread, so heres some newbie question :)

1. Do I need to disconnect the battery for any of this stuff? I think I'm fine with most things but the part I'm unsure about is when it comes to when and how to disconnect the positive (+) terminal on the battery. I don't reeeally want to electricute myself.
2. Any tips in regards to the cabling? Is there, should I or do I need to insulate either the power or signal cables while running them down the car?
3. What's the best way to guarantee a decent ground?
4. How do you remove an Alpine HU (9831) from it's DIN?

Mucho Gracios

[EuroDude]

1. You cant electricute yourself from the 12v battery, unless maybe if you touch positive with your mouth or something - ouch! But yeah you should disconnect it if you are reconfiguring the power cabling. ps. I think its safer to disconnect the negative terminal first, then the positive terminal. Then reconnect the Positive, then negative (check your car manual regarding battery replacement).

2. Ive been told insulating the cables wont help much at all, its better to buy high quality cabling - expensive copper cables that resist oxidization.

3. Run the power cable the opposite side from the RCA and stock speaker cables. Its possible that at the moment in your car, the RCA's are on one side, and the stock speaker cables (for the rear speakers) are on the other side, so you may want to route the power cable through the center - I did this in my Euro and it was acually easier to do that rather than through the side thanks to the solid carpets in the Euro.
Also to avoid alternator noise, make sure the Amp's metal casing is not grounded to the car chassis. My Audison Amp has plastic screw holes so its alright, but if the holes are metal on yours, you may want to screw a thin flat piece of wood (MDF) to the chassis first, then screw the Amp onto the Wood.

4. Dunno, google for "Alpine remove head unit". The Sony's come with a metal key device you stick into the sides to release the clip, which may be similar to the Alpines.



The stock rear speaker cables should still be in the back somewhere near the speakers, and may be connected to the HU. Unless the installers were lazy n00bs.

ps. You can use a cheap multimeter (DC voltage) to determine which speaker wire is '+' and '-'. Play some music and the voltage should jump up and down (use the lowest DC voltage setting on the multimeter - which should be "2", not "20" or "200"). If it gives a negative reading, then swap the multimeter probes around to confirm which speaker wire is '+'.

[Slow96GSR]

1. You cant electricute yourself from the 12v battery, unless maybe if you touch positive with your mouth or something - ouch!...

You can get a burn though. That hurts more then the shock does! Stick yer arm across a set of terminals and see, my boss did that to a Stinger sp1500 and well... 3500 amps was painful!! Duh!

Oooooo now they have the SP2150 (http://www.stingerelectronics.com/web/prods/batteries_power2.asp) out!! Nothing like 5k amps in 1 small package!! Time to start a new order! Anyone here want any? I'll get prices shipped to 9005, where a friend lives so I know the code!, and post it here if that's ok with the mods.

[zorrt]

1. Do I need to disconnect the battery for any of this stuff? I think I'm fine with most things but the part I'm unsure about is when it comes to when and how to disconnect the positive (+) terminal on the battery. I don't reeeally want to electricute myself.


12v isnt enough to "electrocute you but like slow96gsr you can get a painful shock. Best to disconnect incase you accidentally blow a fuse = more $ and time wasted. You can just disconnect negative (10m nut) just undo it and tuck it in somewhere where it cant accidentally earth itself (car body). You can leave the positive terminal connected.


2. Any tips in regards to the cabling? Is there, should I or do I need to insulate either the power or signal cables while running them down the car?

Most say insulating such as wrapping foil around cables are myths. Never tried so I cant confirm. You already know the idea of running power and speaker cables opposite side of each other. Stick to that idea. More work but less chance of noise being induced into system. I use twisted speaker cables. They are round so harder to work with but theologically when wires are twisted, any noise induce cancel each other out due to the way the signal travels. Do a quick google search for thorough explaination. This applies for more than just speaker cables. Network cables work on same principle to help signal quality.


3. What's the best way to guarantee a decent ground?

Best place for grounding is on solid metal blocks on your chassis. One section is where your selt belt buckle is. That bolt it drilled into the car body which makes it a suitable place to earth your amp.


4. How do you remove an Alpine HU (9831) from it's DIN?

I would assume all din plates are the same. Normally comes with 2 stick like thing which you insert into the sides of the din which releases the lock and it should slide right out. If you don't have then you'll have a bit more trouble. Just find 2 piece of metal that can fit into the sides.

[mugeneration]

just to add to what zorrt said, when you do your grounding, it helps a little bit more to sand off the paint as well. Doesnt make much difference really, but it does give a slightly better ground.

[Moya]

Thanks all. One more stupid question, I know I need RCA cables for hooking up the HU to the amp, then the normal wire cables to go from amp to speakers.

But how do I hook it up from the HU directly to the speakers (for the rears, dont want an amp)?

Thanks

[Fr3aKi3]

There should be cables on the wiring loom which are designated for the rear speakers. You can join the cables on the wiring loom with those from the speakers and you're all set.

If you want a solid connection between the cables then remember to solder and heatshrink it.

[zorrt]

Thanks all. One more stupid question, I know I need RCA cables for hooking up the HU to the amp, then the normal wire cables to go from amp to speakers.

But how do I hook it up from the HU directly to the speakers (for the rears, dont want an amp)?

Thanks

You can always use your existing wiring to hook up your speakers if you choose to go without an amp. Just connect the speaker wires when you install your headunit (those grey white purple and i think green ones are your speaker cables).

If you get a wiring harness to suit your car (strathfield car radios etc etc sells them) you wont need to cut your existing cables. Just connect the wiring harness to the one that came with the HU including all those speaker cables) and then connect that to the one on your car.

May I suggest you read www.installdr.com before you attempt this?

[SPL77Civic]

just to add to what zorrt said, when you do your grounding, it helps a little bit more to sand off the paint as well. Doesnt make much difference really, but it does give a slightly better ground.


Whenever creating an earth point, sand paint right back to bare metal and preferably use a bolt to ensure a really good tight earth.

Sanding back should be done, it only takes a little effort and the difference can be very noticable, if you just earth to a painted or poorly sanded area, you run the risk of a dodgy earth an dodgy earths are the cause of many issues like engine noise, amps running hot and into thermal protection, blown rca outputs on headunits etc.

Do it properly the first time and you dont run those risks.