Please help - do I need to rewire for replacement receiver

[AttyGirl]

I recently purchased a 2002 Boxster as my second "fun" car (yes, women can have a midlife crisis also - we just get them earlier. . . ). I want to replace the factory stereo and add Bluetooth and aux. I found an Alpine receiver. I also found some new door speakers as the current factory ones do not appear to be working (at least I don't think that they are - when I fade to back there is no sound). I don't know a lot about car stereo systems - but I went on Crutchfield and spoke with a guy to confirm what I wanted to purchase.

Here is the question - I am being told that I HAVE to bypass the factory amp because if I don't, the sound will be worse than it currently is with factory unit. In order to do this, I will need to rewire the entire car. Crutchfield told me that the two harness sets worked with a 2002 Boxster - the guy who is going to install is the one telling me that it won't work. He said that the problem is that the Alpine unit will amplify the sound, then the wires will de-amplify it, and once it passes through the factory amp, it will be re-amplified - and finally the sound will go to the speakers and be crappy. He told me that this is a Porsche issue (and one of the joys of ownership).

I am confused (to say the least). If it needs to be completely re-wired in order to sound good, I'll do it. It's just after browsing through info on the web, I'm not sure if I need to. The reviews on Crutchfield for the harnesses say nothing about reduced sound quality - and several of the posts are with respect to Porsche Boxsters.

Also, the guy at Crutchfield told me that I should spend money and replace the dash speakers - and the guy installing said that I should only replace the door speakers. Thoughts??

I'd really appreciate any information. Thanks!!

[juicepro]

Here is what I recommend and it won't cost a lot. Buy an alpine cde-103bt from crutchfield, use the existing amp to power the dash and door speakers off the pre amp connection on the back of the deck. I recommend you replace the dash speakers with the alpine ones also. You can leave the door speakers alone for now. They are just woofers for bass only.
Later on you can install speakers in your rear storage compartment and use the alpine decks built-in amplifier to power those. I'm running 4 Polk audio 3.5" in mine, they sound great.

[Nimbus117]

The door speakers are normally subwoofers so the fader wont work with these, it will however if you plug some rear speakers into your amplifier. You should be able to hear some noise from the door speakers - just bass though so no medium or high frequencies.

I used the head unit to power the dash and rear speakers and an Alpine amp to power the door subwoofers. You dont need to re-wire everything, I did however put in new cable from the headunit to the dash speakers. I have a Pioneer double din so ran a 3m phono lead from the headunit to the amplifier. If the headunit you are getting doesn't have phono sockets you can use a LOC (line output converter) from the speakers. It's not a big job, biggest improvement are the rear speakers.

[AttyGirl]

Crutchfield no longer carries that model. I'm looking at one that I think may be the new model - 147BT. They suggested that I replace the dash speakers with Helix Blue B4x. I was told that if I install both of those I can run it through the stock amp. They told me that they don't really know for sure what the specs are for the stock amp but think that it has enough power so I don't need to replace.

I was also told that the rear speakers won't help much when driving because I really only use it with the top down. Based upon your reply (and the other one I received), the rear speakers are a good addition. Did you upgrade any of your wires?

[AttyGirl]

I'm so glad that I posted my question because I told my soon-to-be fiancé that the door speakers had sound because I felt vibration and that I thought they were subwoofers!!

Why did you decide to power the dash and rear speakers from the head unit? I really don't know very much about car stereos so I apologize if that is a stupid question. . . . .

If I use the harness from Crutchfield, I assume that means I would be connecting the head unit to the stock amp - and the dash/door speakers would run from the amp (is that how it is set up currently with the stock head unit?). Crutchfield said that the amp would be able to power the new dash speakers (Helix Blue B4x - they recommended).

[AKnowles]

FWIW, I replaced my stock apmplifier and speakers. All of them. I'll be putting in a real set of subwoofers in the door this fall. Unlike many here, I'm a beleiver in replacing the stock wiring. If you just want better sound than the stock speakers then go ahead and just repalce them and use the adapter to use the stock amplifier too.

If you want the best possibke sound for your car, then consider a new amp, new wires, and new speakers. It will cost more - a lot more if you don't do it yourself as it requires removing your dash, door panels, and fishing wires through a lot of nooks and crannies (particulalry the existing rubber boot between the door and car frame) - but you will get much better sound.

[Nimbus117]

Originally I wired in a 6 channel amp but I got really bad alternator whine. Eventually I found using an old 2 channel amp and connecting the front and rear speakers to the head unit got rid of it. Anyway, the headunit's amplifier is plenty loud enough and the extra power of the Alpine amp over the Porsche one really brings the door subs to life.

The sound difference with the new headunit and rear speakers is impressive. I did replace the dash speakers but that was quite a subtle improvement. You dont need to replace all the wiring etc, if there is a difference you certainly wont be able to hear it - is a car after all. A bit of sound deadening in the doors is far more worthwhile.

Cant comment on the Crutchfield wiring as I just added a couple of wires to the cars ISO connector but here's a how to on the rear speakers:

Pelican Technical Article: Installing the Boxster Rear Speaker Kit - 986 / 987

[gavinyuill]

Originally Posted by AttyGirl

Here is the question - I am being told that I HAVE to bypass the factory amp because if I don't, the sound will be worse than it currently is with factory unit. In order to do this, I will need to rewire the entire car. Crutchfield told me that the two harness sets worked with a 2002 Boxster - the guy who is going to install is the one telling me that it won't work. He said that the problem is that the Alpine unit will amplify the sound, then the wires will de-amplify it, and once it passes through the factory amp, it will be re-amplified - and finally the sound will go to the speakers and be crappy. He told me that this is a Porsche issue (and one of the joys of ownership).

I am confused (to say the least). If it needs to be completely re-wired in order to sound good, I'll do it. It's just after browsing through info on the web, I'm not sure if I need to. The reviews on Crutchfield for the harnesses say nothing about reduced sound quality - and several of the posts are with respect to Porsche Boxsters.

Also, the guy at Crutchfield told me that I should spend money and replace the dash speakers - and the guy installing said that I should only replace the door speakers. Thoughts??

I'd really appreciate any information. Thanks!!

This is complete nonsense. The head unit you are looking at has both amplified and non-amplified outputs, as nearly all systems do these days. When I replaced the head unit in my 97 base, I used this adapter:

Metra Part # 70-1787 | Volkswagen wire harness | Audi wire harness | Metra Online

it plugs straight in to the boxster harness and provides non amplified feed to the amplifier and amplified feed direct to the dash speakers. There are a couple of wires to connect to the harness that comes with your head unit, but all the wiring can be done outside of the car, there is no need to touch the harness in the car at all. Please take your car somewhere else if they insist on rewiring it.

There is a handy DIY here:

Pelican Technical Article: Changing Your Boxster Stereo Head Unit / Installing Boxster Ipod Integration - 986 / 987

As far as replacing speakers, the dash ones are the ones to do, it does make a big difference.