I have the standard US sound system (10 spkr). I'm thinking of upgrading the woofers under the seats (they don't seem to keep up with the mids and tweeters). I've searched the forum for as much info I could get before I start the actual upgrade. But I have a few questions, if anyone could answer them, that'd be appreciated.....
1) What's the exact dia size of the speakers under the seat??? What's the Mounting depth???
2) Are the speakers really rated only for 40w max??? This is one reason why I want to upgrade them. I rather have a speaker that could handle 40w nominal and 100w max.
3) What's the best way or what should I look out for when taking out the front seats???
4) Is the audio signal already filtered (high-pass/low-pass) before it gets to the oem teenie-weenie amp in the trunk???
5) Is that teenie-weenie amp used by anything else??? It would be really cool if someone sold a aftermarket wiring harness for it.....

Thanks for help!!!.....

 

I looked at upgrading my system a few months back however I was using an aftermarket stereo specialist to do the work. Although I did not finish the job I do remember a few of the details discussed about BMW stereo upgrades. First and for most you will need to by pass the amp supplied with your system because it does not provided enough power to push aftermarket subs. He recommended an Amp by Phoenix Gold (not sure of the exact model). He also recommended the JBL Clean Sweep to clear up the sound. This device attaches to inline with your factory unit and splits the signal for better sound. You can a do a search on JBL and find the specs. There are also some slim line aftermarket subs producing great sound that already fit the enclosure under your seats.

I will contact the shop in the morning to get the details and post the details tomorrow.

B2

 

I have the Logic 7 which is very good, but the bass is a little muddy. I took my aftermarket system out of my M3 before I sold it, and plan to put my 600 watt Diamond Audio amp and 10" Diamond Audio sub in the trunk. I've been told this is possible with I-drive, and has no effect on the main system. Should be pretty nice, and my God I have a huge trunk now so why not use a little of it.

 

Thanks B2round, that would be great if you could get the info.....
Darkside, I want to throw a 10" subwoofer in my trunk too. My overall plan is to replace the so-called woofers under the front seat, with something more efficient. Nothing that will thump the my license plate off the car, but a strong and responsive speaker that will fill the bass void. Of course, replacing those speakers I'll need to replace/bypass the teenie-weenie amp in the trunk with a better one. Which is why I'm hoping there's a clean full-range signal going into that oem amp that I can tap off.....Once I get that going, I'll add a subwoofer to fill in the low-freq bass.....Then I'll thump the license plate off the car!!!

 

Check out www.bavsound.com.

I just say their add in the latest issue of Roundel. Don't know how good they are.

 

Hi Coastal_CV,
The problem you will be facing is not only regarding the low power of the oem amp. It is also due to the head unit rolling-off low frequencies at high sound intensity (volume). In order to protect your oem speakers of the car, while increasing the sound volume, the head unit keeps increasing the low frequencies (bass) unitl it reaches a point where it stops the bass at certain level and increases the rest of the sound frequencies, so no matter what amp and speakers/subs you buy, the bass will not be always there at high volumes.

In order to solve this problem you have to buy a de-equalizer, which B2round referred to. It is actually JL Audi CleanSweep, not JBL. Anyways, this device will de-equalize the frequencies curve you are getting from your head unit to a flat curve that you can control on your own using a seperate equalizer, or if you want it more simple, you can just de-equalize the signal you are going to give to subs instead of altering all the sound properties of other speakers in the car.

So basically buy 1 or 2 subs, an amp for the subs, and a JL Audio CleanSweep. Split the signal coming from the head unit, connect it to the CleanSweep, then to the amp, then to the new subs in the trunk. This is the easiest way to get bass in my opinion. It will be much easier than trying to change the OEM subs under the front seats.

Shebs

 

I disagree. I think the easiest way to get clean bass is to put in a 12" sub in the trunk, cleanly. Not as pretty and takes up trunk space, but your most bang for your buck. The teeny weeny amp in the back left of the trunk drives the two 'subwoofers' under the front seats, only. The rest of the speakers are driven by the head unit itself, unfortunately. I spliced into the output of one of the channels going to the front underseat subs to get the signal, then ran it into a line-level converter, then to the JL 250/1 amp. The battery is in the trunk which makes for an easy install..

My car sounds much better now....

check it:

http://forums.e60.net/index.php?showtopic=11606

P.S. I too would like to know if the signal that goes to that subwoofer amp in the back is filtered or not. If it doesn't contain bass-only frequencies, then that would make upgrading the rest of the speakers MUCH easier!! I suspect the head unit sends a low-pass frquencies to that little amp, though it could be the little amp filtering them. If you find out, let us know!

 

When I discussed this with the installer of my system in my M3, as I understand it the subs under the seat are left in and can be demphasized by how the base is controlled on the main system. I really didn't understand it but they have done a lot and did a hell of a job on my M3. I just want a cleaner base with more low end punch, but nothing to interfere with the main system.

 

You say that the amp powers the sub woofers under the front seats only, right? No, because I have only 8 speakers, without the two subwoofers, and i still have an amp. Can you explain this to me? I am sure that my speakers are driven by the amp, since I have an amp and no subs.

Shebs

 

Apologies for the delay but as promised the name of the subs are 8" Earthquake SWS. They have great sound quality and fit right into the current sub compartment under you seats. I am not sure about the price but I am sure you can find more information on the web. I think I was quoted a total install price of $2000 for the JL Clean Sweep, Phoenix Gold AMP and Subs.

It really sounded nice in BMW at the shop. I ordered the parts but decided to trade the car instead

B2