i have the hi-fi option in my car.I replacing all speakers exept the dashboard gonna be components...i have very good quality HU unit as well.I'm not planing to upgrade the amp.

qustions:

can i feed the speakers from HU and the woofers from amp?

is factory amp bridgeable?

what is the best solution for conection?

Any reply are welcome.Just wanna solve this and start the install

 

If you have the HiFi option then all the speakers are now fed off the amp. Assuming that your head unit feeds the amp on all channels you can cut into the outputs from the amp to the front speakers and feed them from there. I don't think you would get good results feeding the fronts directly from the head units, different level of power to the fronts, mids and backs would be a challenge.

 

ok...i was asking in ABT yesterday on setup and they told me i have to change the amp.Because it will not work.I just dont believe that but question follow= shut i just get amp?

 

I guess it would depend on what speakers you are putting in. I just know that when I did my upgrade I started with the speakers, Focal 100KP's in the dash (corssovers in the trunk with new wires to the dash), Focal 5WS in the doors and Focal 100 Slimlines in the rear. Used the OEM amp and it worked fine, although it did not have the power of the new amp. A month or so later I put in the JL Audio 6450 6 channel amp. With a 6 channel amp you only need one amp, it uses two channels for the front, two channels for the rear, and two channels blended for the door subs. Sounds great. I did put in new RCA cables from the HU to the amp, using an adapator I got from Becker. Used the stock wires for the doors and rears as new wire would be a pain to run.

 

do you hear big improvement with the new amp over the existing one?

 

The Focal speakers take a bit of power to really produce, so with the OEM HU you had to set the volume pretty high to get much out of the speakers. This in turn lead to more distortion as the OEM HU does not have a very high output. With the JL Audio amp the output level of the HU is much lower. As I remember there is actually a low level output socket and a high level output on the HU. I think I used the low level output. But with the power of the amp this is where the volume is really produced, and the signal/sound is much cleaner. I am able to use the balance and fader on the HU.

So the answer is yes, the sound using the amp is much better. But remember that the OEM HU is only about 40W (don't remember exactly) and your HU may be much higher. If that is the case than you might not get as big an improvement.

 

So you used factory wires with you setup exept the dash correct?...I have one JL amp but only 4 chanel.If i decided to use that JL i have to feed rear speakers from HU correct?

 

I doubt the OEM HU have 40W. Maybe 40W maximum but also at maximum distortion. Continuous, it is most likely not gonna go over 20W per channel. That typically includes most aftermarket headunits, possibly including the one that the OP had purchased.

With the stock headunit powering the speakers, it is ideal to go with speakers that has a high sensitivity. Every 3db increase in sensitivity is equivalent to double the power. 40W RMS amp with 90db speakers yields the same output in volume as 20W RMS amp with 93db speakers.

If you don't want to use an aftermarket amp, then I suggest you go with speakers that has a very high sensitivity to get more volume with less distortion. I would highly encourage to use a separate amp for all speakers. However, if you are not willing to purchase another amp and would like to use what you have, which is the JL 4-channel, then the best way would be to use 2-channels for the front and 2-channels for the door mounted subs. The rear speakers aren't that important for a proper soundstage so you could either leave them out or use the headunit's amp (at low volume) for a slight rear fill.

 

The only problem with using two channels of a 4 channle amp for the doors is that the doors are subs, so you need to deliver only the low frequency to these speakers. May be possible with a 4 chanel amp, not sure though.

 

There are some amps with separate built-in crossovers for channels 1 & 2 and 3 & 4. Therefore, that shouldn't be a problem. Don't know if the OP's JL has that feature though. If not, that can be achieved with either through the headunit or an external electronic crossover. If through the headunit, if it's got 2 sub-outs, then connect both directly to 2 channels on the amp. If one sub-out, just use a y-cable and connect both ends to 2 channels on the amp. Then use the headunit's built-in crossover. OP did say he already has a headunit but don't really know its features. Really depends on what type of equipment he has and how much more is he willing to invest if his current equipment comes out short.

 

I stopped by my local mobile audio shop and my guy said to upgrade the head unit first and see how the speakers sound. I am putting in a single DIN and I'll get a storage cubby for the bottom panel with all those useless "equalizer" buttons. Are you doing the same or oare you doing a double DIN and moving the climate control?

 

i upgrading single din unit (i dont think double din looks good in this car).I just installed new speakers all around and have new 6 channel amp delivered thursday.I'm exited to have everything done.
The new HU should help if you put something decent.I have change my HU to PIONEER DEH P800PRS which is amazing.This unit have 16 band equalizer and coper body.
I will post pictures by next weekend with new install done...btw speaker upgrade is easy if you do research and choose the right size.

 

Try to pm DHARN and he will help i think....I did very simular setup like him and i dont think you go wrong...BTW CHEEEERS DHARN (thanks for responds)

 

fourempties - The audio shop has it backward. The speakers are the weakest link in the OEM system. Any HU will sound bad through bad speakers, and the OEM speakers are pretty bad. I did focals all around, with a JL Audio amp, still using the stock HU and CD changer. I will hold my system up to any HU playing through the OEM speakers.

So my advice, start with the speakers, next the amp, last step should be the HU.

 

I actually have a couple of point of views and both are based on my personal experience. Even though I do agree that the speakers are generally the weakest link in an OEM system, sometimes it can also be the amp. Rather than start with the speakers first and next the amp, my suggestion is to just do both the amp and the speakers at the same time.

Starting with the speakers first without the amp, it really depends on which aftermarket speakers are used. If it is something that is not sensitive (meaning a lot of the good ones), the OEM amp will just have a hard time driving them and increasing the volume to make up for it would just lead to more distortion. Going with mid- to high-sensitivity speakers without upgrading the amp in the beginning may be a better starting point but a lot of those speakers are just decent, not really great speakers.

The other side of the argument, yeah, it is possible to improve the sound of OEM systems with a headunit change. Been there, done that....a couple of times (even though I usually do audio system upgrades -h/u,amp/speakers- in one shot). I really can't explain why but, yeah, there were improvements (but these are in one of my BMWs and MBenz, so I really can't say for Porsche systems but they all should be similar). A headunit change alone can also yield more audio tuning capabilities that is absent in an OEM headunit but possible with aftermarket headunits, plus you get MP3, ipod, USB, and whatever capabilities.

IMHO, both are good ways to start an upgrade. One can start with the headunit, and if not satisfied with the results, continue to do an immediate upgrade with the amp and speakers. And vice-versa.