Mixed Soundsystem Help

Fri Mar 26, 2010 6:18 pm

Alright lads,

ive spent most of the day undoing the previous owners BS when it comes to wiring, now i need a little help with a few points.

the car is a late 316 so front battery.
ive run a power cable to the boot for a 4 channel amp. i plan to run 2 speakers on the rear shelf, and 2 speakers in the front from this amp. ive plumbed in an rca cable (opposite to the power) for this

where is the best point to earth the amp in the boot? the previous owner has ground off some paint on the boot latch, but this seems a bit crappy to me i would prefer to find a nice fat bolt. does anyone know where there is one in the boot?

second question. the head unit is quite i nice one i think, the problem is it only has 1 pair of rca cable outputs. At a later date i want to add another amplifier and run a sub off that in the boot.

my question is would i be able to by an RCA splitter and have 2 pairs of rca cable running from the back of the head unit to the boot? would i notice any difference in sound or power as the head unit would have to put out to 2 sources? would it damdage the head unit?

thanks in advance,
matty

Sat Mar 27, 2010 8:30 am

I've used a hex headed screw at the bottom of the drivers side comprtment to eart the 2nd battery i've fitted and not had any problems.

re splitting the signal to the future 2nd amp.
You could just split the signal just prior to it entering the 4 channel amp your about to fit.
That'll save running another 5M pr of rca's. You'd only need 1m or 2m leads instead.

Sat Mar 27, 2010 9:19 am

You can fit a splitter to the RCAs to run two sets of speakers, but you won't be able to fade the front/rear speakers to get a balanced sound in the car from the head unit (you could adjust the gain for front and rear on the amp to perform a a similar job, but it's fiddly and time consuming depending on how accessible the amp controls are). Your sound stage should be at the front of the car (you wouldn't listen to music with your back turned) with the rear speakers used for fill in and to provide some bass (bass is non-directional, so doesn't matter too much where it's situated). If the head unit has separate speaker cables for front and rear speakers I recommend you buy some adaptors that have speaker cable inputs at one end and RCAs at the other. You can buy these from any decent car hi-fi shop. Then you run 2 RCAs through the car to the amp and have the ability to control the sound. If you're going to the trouble of running cables and fitting an amp it's worth doing the best job possible to get the best outcome.

Sat Mar 27, 2010 9:03 pm

ok thank guys.
another quick question will i be alright running a single 0 gauge cable, then splitting it to power the two amps?

Wed Apr 14, 2010 8:27 pm

Single 0 gauge will be plenty good enough - unless you're going for massive power!!!! Make sure you got a fuse inline!!!

A lot of amps these days also allow daisy chaining - so you'll have an input for the rca's you've run and then an output so you can run a short rca straight to the other amp!! Prob better than using splitters, although you can do that if necessary!!
As above though, you still won't be able to fade front to back, but if you set it up using the gains on the amp, it won't matter (unless you're aiming to please people in the back sometimes!!), how often do you adjust the front/rear fade???

Sat Apr 17, 2010 1:20 am

miniblob wrote:Single 0 gauge will be plenty good enough - unless you're going for massive power!!!! Make sure you got a fuse inline!!!

A lot of amps these days also allow daisy chaining - so you'll have an input for the rca's you've run and then an output so you can run a short rca straight to the other amp!! Prob better than using splitters, although you can do that if necessary!!
As above though, you still won't be able to fade front to back, but if you set it up using the gains on the amp, it won't matter (unless you're aiming to please people in the back sometimes!!), how often do you adjust the front/rear fade???

ok man thanks for the help.
recon that the 0 gauge will be hench enough to run the 500rms sub i bought on a random impulse? i cant afford the amp right now, but will it work in the future?
gunna need a fat fuse in there! lol. can you even get 80amp fuses?!

i always aim to please people in the back. but thats another matter.

no but your right. screw the fade. i never liked it anyway.

Sat Apr 17, 2010 4:47 am

Please dont use the words such as "Hench" and "Fat" please they are very annoying and dont suit you unless you drive a BMX and are 23 years old with no aim in life

Sat Apr 17, 2010 10:25 am

randomspeedfreak wrote: gunna need a fat fuse in there! lol. can you even get 80amp fuses?!

Depending on which type of fuse you pick,you can get them up to 300amps

no but your right. screw the fade. i never liked it anyway.

If you use time correction, theres no need for it anyway.
It's all about how it sounds from the drivers seat

Mon Apr 19, 2010 1:49 am

you might have trouble finding a fuse block for 0 gauge and 80amp fuses,a 0 gauge block will be anl fuses that usualy come in 120amp or larger,80 amp fuses are normaly the glass type agu(?) fuses

Mon Apr 19, 2010 4:50 pm

Overkill on using 0 gauge, I would rather go with a decent 8 gauge or a 4 gauge if using 2 amplifers. Then get a decent fuse block at the back to split the power to the 2 amplifers, very few amps will accept a 0 gauge cable in any case.

Also your woofer power does not matter, a woofer does not make power, hence it does not need power, it is a passive device which uses the power and converts it into motion.

Amplifers need power and thats where the power cable comes in, always have a fuse near the battery , this is to protect the car , incase the cable gets knicked or shorts to the body , it should be the same or slightly more then the rating on the amplifer. If amp has 2 x 30A fuses, front fuse should be 60A if 2 amps are used then front fuse should be 120A . The rear fuses are to protect the amp against overcurrent draws.

So going to your original question.....what cable

4gauge is prefered , 8 gauge willl work.

Earth for the amp , use any good steel , expose it with some sand paper or a grinder, strip back the paint, then drill a hole and prefered method is a bolt with locking nut , and washers. Once it's tight , use some primer over the bare metal so it does not rust.

2nd Question , depending on the amplifer some have an Aux output which will allow you to get the same signal from the headunit and you would not need to run an extra RCA cable front to back , failing this you would use a Y-Splitter to take the 2 signals (l&r) and make em 4 signals, 2 L and 2 x R.

You would not get a degridation of sound if you use Y-Splitters either in the front Headunit (1M - 2F) or rear (1F - 2M)