Fitting Aftermarket HU Questions

[S4_dan]

Hi,

Done a search but can't find exactly what i'm looking for.

Got myself an 1kw Amp and a nice sub, along with a sony HU i've had for a while but never fitted.

Pulled my Concert out and checked the wiring. The standard ISO leads has correct power backup, earth etc on it but the speaker ISO plug only has four wires (Front speakers only)

The rear speakers seems to be fitted into a small blue block with much thinner wires. I presume these wires go to the amp & sub already fitted? Does the said amp also drive the rear speakers?

On that basis, what are my options for getting the rear speakers to work?

1) Buy an ISO adapter harness?
2) Rewire the rear speakers directly to the Sony HU?
3) Would i need a 2nd amp for the rear speakers or would the HU drive them ok?

Any other pointers would be appreciated.

Cheers,

Dan

 

[ScottD3]

1) Buy an ISO adapter harness?

You can buy an ISO adapter but wiriing it up your self is easier.

2) Rewire the rear speakers directly to the Sony HU?

You can wire them in directly or use the orignal Audi wiring that goes in to the amp. The rear amp powers the rear speakers and sub.

3) Would i need a 2nd amp for the rear speakers or would the HU drive them ok?

Head unit or orignal audi amp will be fine.

When I wired my head unit up I used the stereo speakers in to the orignal Audi wiring which went in to the amp.
And all works fine.

Why not use the amp to power the speakers or a 2nd amp?

 

[aragorn]

The audi amp is pish, and is also built into the OE subwoofer on an avant, so will likely end up in the bin when you fit your nice sub.

Your options are basically to rewire the speakers into the head unit, or do what i did and buy a second amp to power all four door speakers.

I'd seriously recommend the latter, giving the speakers a nice true 50-60W RMS power rather than the ~20w you'll get from a head unit really makes a difference.

 

[S4_dan]

Ok, i've fitted my sony hu and for time being i've connect the rear speakers to and hu harness as normal and used the antenna live for powering the amp. I've got sound in all 4 speakers and amp. HOWEVER, i keep getting like 'spike' surges through the rears and sub. I've turned bass right down on HU but no difference. Still getting a loud crackling spike noise every few seconds or so.

 

[S4_dan]

I do have a smaller amp sat in a Saab 900 Turbo i'm restoring so I might pinch that to run the 4 speakers. Sony HU says it gives 50w per channel so would fitting an amp be much difference?

 

[S4_dan]

another question, does the internal nearside cloth trim need to come out to remove amp/sub? The sub i have is already in an enclosure but might look to adapt it so it minimises the loss of boot space for the pushchair, toolbox and shopping etc.

 

[ScottD3]

another question, does the internal nearside cloth trim need to come out to remove amp/sub? The sub i have is already in an enclosure but might look to adapt it so it minimises the loss of boot space for the pushchair, toolbox and shopping etc.

Yes.

 

[aragorn]

Your Sony HU will be rated at 50w "MAX" power and something like 20-25w RMS (real) power. A proper power amp will be rated usually at least 50w RMS.

The JBL GTO4000 i have in the avant will do 50w into four channels, and the JBL i have for the saloon will do 75w into two channels

 

[S4_dan]

Right, got OEM amp/sub out. Now struggling to get the pesky door cards off to rewire the speakers. tried a search but coming up with nothing??

 

[ScottD3]

The door cards lift up once you removed the screws behind the door handle.

 

[aragorn]

two screws at the very top edges as well.

 

[S4_dan]

I got two screws out at the side near top of the trim and one from in door handle area. But it is still stuck solid?

So there is only 3 screws securing the trim?

 

[tonya4]

after you have removed the screw near the handle,remove the small trim behind it and there is another 2 screws behind it.

tony

 

[S4_dan]

after you have removed the screw near the handle,remove the small trim behind it and there is another 2 screws behind it.

tony

The pull/close handle trim? Or the swing handle that opens the door?

I've tried to remove the pull/close trim but it wont budge and i dont wat to break it like i did with the wooden trim after following a bum guide on auditech world forum

 

[tonya4]

the pull/close handle mate.It will be tight,but will come out.

tony

 

[AndyMac]

You don't pull it out, you just push it down to reveal the 2 main screws.

 

[Foxmeister]

2 screws either side at top of card, then one under door pull, when you take the screw out pull the plastic down, it splits from rest of handle, theres a further 2 large screws behind this, then hold the door card by handle and lift it up off the door.

 

[S4_dan]

Trim in green circle won't budge.

Trim in red circle is secured to door trim from rear of trim. I know 'cos i've broken a clip on back of it tryin to pry it off.

So i'm baffled.

 

[tonya4]

the bit of trim in question is behind the handle,you can just see the top of it in your pic.Its the bit that the screw goes through.

tony

 

[Bradderz_1988]

I'm sure the panel has a blank cap about in the centre behind the grab handle and iirc the grab and chrome handle bit comes of with the door card when you lift the panel off the door !

 

[AndyMac]

Remove the screw behind the grab handle where the blue arrow is pointing then push the cuff down which the red arrow

 

[S4_dan]

Yup, sussed it now! lol. Was looking too much to realise that the little piece pulled down.

Well, card off, speaker wire unplugged.

What is the most preferred way of running new wire from the speaker?

Continuing to use Audi's wiring from speaker to B Pillar

OR

Connect the thicker speaker wire i have direct to the speaker and feed through the B pillar/door connector?

 

[AndyMac]

run new cable all the way, release the rubber boot between the door and the pillar to help guide it through

 

[aragorn]

Isnt the OE cable pretty chunky?

I just made my connections at the head unit ISO loom, as i couldnt be ***** messing with the doors.

 

[andybnwc]

Its really not worth running new cables through the doors unless A they are already damaged or B doing a full door build

 

[S4_dan]

The wire to the front speakers are fairly thick. The wires for the rears are thin. There are thin from HU to the amp then to the speakers. So was wanting to rewire with larger guage wire.

 

[AndyMac]

There is no stock speaker wiring from HU to rears. The rears run off the amp in the boot, the wiring from HU to amp is for low level pre-outs, which you definately cannot use for speaker cable as it is only single wiring and a screen, the screen is earthed, so if you try and use this it will fry your HU. You can by all means tap into the rear wiring at the amp so you don't have to route it through to the doors, but you'll still have to run new cable from HU to boot.

 

[Foxmeister]

Not much point in upping the gauge of the wire, unless your using a decent powered amp and front speakers that will benefit from it.

16 gauge is more than enough for most standard, slightly amped stuff.

 

[S4_dan]

Yeah i'm aware that I have to rewire upto the OEM amp/sub connector if leaving original speaker wire in situ from there on. Those wires to the speakers are still thin but not as thin as from the HU to the amp connector. Front speakers wiring is fine.

I'll prob just run all the new amp wires and speaker wire along the Nearside trim to the boot and join speakers wires onto old amp connector.

Shame i'm not fitting this into a vauxhall as the trim is so ****** easy to remove and replace!! lol