Hoping for some quick advice if any to avoid a $200 rewiring of the car.

I have a 2005 Coupe and everything was stock.

I just purchased the Alpine X305 head unit and very pleased with it. Connects to my Iphone 3G, charges and plays as expected. I also had the Alpine Bluetooth adapter installed as well and this works perfectly with the Iphone and my 8700 Blackberry.

The install was done by techs at Futureshop and actually I was pleased with the work and the install charge was cheap!

Afterwards though I realiszed that the rear speakers were not engaging. Checked the fade and all audio settings. All speakers and the amp are still all infinity stock.

The suggestion from the techs is to rewire (for $200) and by-pass the amp and run from the HU to the rear speakers.

I am hoping to learn a proper solution and maybe even do this myself.

Thanks all!

 

I have the exact same deck and thought the same thing. At lower volumes I had no rear sound, but it acts more like a sub and only puts out lows. Turn it up louder and listen and feel the back wall.
Did they put on the wiring harness?

 

Yes...I believe they did...

Harness and an antenna...

Recoton AAMP BAA22 and Recoton AAMP BHA1784

I'll have to do another sound check and tweak my audio settings i guess but a significant difference having most of the sound in the front.

 

Keep in mind that there is no true rear speaker in the car, so if you fade it all to the rear you won't hear anything. If you leave the fade in the front or just in the middle on higher volumes you should hear the "rear" speakers kick in.

 

this is what i bet the issue is



you have a fancy head unit that has filter built in for high pass and low pass.

the tech probably set a high pass filter on the head unit to limit the bass to the front speakers. the car only accepts input from front input on your head unit and then splits to rear at the amp so all signal modified for front affects rear as well.

most members put capacitors at the door it self to limit the bass.

now the frequency is as follows and this is a rough each user picks his settings

subs: 60hz-80hz and below

mid bass: 63hz-300hz

mid range: 200hz-3k

tweeter: 3k-12k

what they did was set a filter and block all frequency below a certain range so limit 80 hz and below and that is where the main bass notes are at between 30hz-80hz.

if you disable the filters on your headunit you should be able to hear the bass on your speakers in the rear

again keep in mind the speakers in the rear which have a port hole is subwoofers no voices will come out of it but low end notes.

cliff notes: disable all filters on the head unit since front wire on head unit is split to all speakers in the car.

 

Also adjust the front to rear fader so that it's 100% to the front. When I installed my new deck I thought the same thing, and after re-adjusting the fader to the max in the front I the woofer came back to life.

Just need to install the bass blocker caps on the door speakers to get some real bass now

 

I have seen other posts regarding capacitors in the doors. Its what confused me a little regarding if the rears acted more like subs or were true rear speakers.

Thanks for the comments guys.

 

If you disable all the filters, which helps the mid-subs behind the seats, what happens if you have a separate sub in the trunk. Will it still work?

 

Depends where the lead for the sub in the "trunk" is connected. If it's connected to an aftermarket head unit that has a sub woofer output, and that sub is connected to that outlet, then it won't matter what the front and rear outputs are doing - if the sub output is on, the sub in the "trunk" will work.

If the "trunk" sub is connected to some other outlet, it's going to be handled however that outlet is set up. If the low-pass is off, the sub will not do much. If high-pass is off, you should hear the sub.