Once upon a time there was a little boy who owned an E60. This little boy liked music, but his car stereo could not play anything with more bass than what is in a 9 year olds voice. When he tried, the speakers would sputter and spit and generally sound like ass. One day the little boy got fed up with it. This is the story of what he did...

Now I am not a professional installer. I?m just a guy who likes to break things, so take this post for what it is - a crazy don?t-try-this-at-home internet posting.

Equipment List:

Alpine PDX 1.600 (600wx1 @2 or 4 ohms) 262.45

Alpine PDX 5 (75x4/300wx1)

Audiocontrol LC6i 6 channel Line Output converter 75

Earthquake SWS-8x (2)

Infinity Kappa 42.9i 4 1/2in speakers (50w RMS 150w Peak)

Infinity Kappa 6022i 6 1/2in speakers (60w RMS 180w peak)

Rockford Fosgate P2D412 12" Subwoofer (50-250 watts RMS/500 watts peak power) 192.95


Add-ons:

SRQ Customs sub box

BMW OEM Trim piece & cubby

I wanted to perform the simplest upgrade to the stock system I could while reaching my goal of hearing/feeling more bass. I did not really want to mess too much with pulling the car apart as I know (from prior BMW installs) these cars are engineered in such a way that makes adding and running wiring anywhere a nightmare. My plan called for switching out the rear deck speakers with higher quality speakers and switching out the under seat woofers. I also planned to add some trunk based bass and a pair of front 6 1/2" door speakers (which it turns out I didn?t need).

The first thing I did was replace the under seat woofers. Basically, I followed the BMW e90 Sub and Amp Upgrade DYI that's floating around. I removed the stock woofers added some polyfill to the enclosure, installed a spacer, filled all the gaps with hot glue and then installed the SWS 8's. Next, I removed the rear deck grills and stock speakers and replaced them with Infinity Kappas.

I ran the rear left and rear right deck speaker output along with the sub left and sub right output into the LOC. The LOC can sum signals into a number different combinations. For my installation I needed 3 outputs (2 for the subs and 1 for the mid/highs.)

One of the hardest part of these installs for me in finding the right positive/negative speaker signal wires. After some detective work (and trial and error) I found out the following:

Left Front Sub (coming out of little sub amp in trunk)

-Brown with Yellow stripe = negative

-Orange with White Strip = positive


Right Front Sub (again coming out of little sub amp in trunk)

-Brown with White Stripe = negative

-Red with Blue Stripe = positive


Left Rear Deck

-Black with Purple Stripe = negative

-Black with Red Stripe = positive


Right Rear Deck

-Yellow with Brown Stripe = negative

-Yellow with Black Stripe = positive



The high output and one sub output from the LOC went into the PDX 5 and the other sub output went into the PDX 1.600. Since the PDX 5 sub output is 300w RMS at 2 ohms and the SWS8's are 150ea RMS I ran the subs in parallel (pos/pos to positive on the amp and negative/negative to negative) to split the wattage between the two. It's a perfect match. The rear deck speakers are 50w RMS and the amp output is 75w RMS. I did this to ensure the smaller speakers always have clean power. This will keep them from blowing. I ran the output from the PDX 1.600 into the 2 12" subs in the trunk enclosure. The trunk enclosure was filled with polyfill appropriate for its size then I just dropped in the 12's and put it in. The SWS are crossed over at 250MHz. The trunk subs are crossed over at 100 MHz and the rest of the system picks up 250MHz up.

Interesting point? the stock subs are really mid-woofers and not true subs. If you cross them over lower you will have a mid-bass hole (where a significant portion of music takes place). This was my initial reason for adding the 6.5 in speakers (to pick up 100 MHz-up), but I found the SWS8?s handle 250 MHz and below very well.

The soundstage is rear biased enough to round out the soundstage nicely (with the blance controls centered). The only thing remaining is to Dynamat (or Fatmat) the rear trunk lid area for rigidity. The area behind the carpet cover (where the emergency latch is located) is under some stress from the subs (there is no place for the air to excape...I wish I had a ski port or better yet fold down seats!) and when the system is played the loudest it shivers a bit. The Dynamat will fix that.

I'm going to skip talking about tuning the system (adjusting gain, etc.) and running wiring because you can find that information all over the 'net and if you're doing this yourself you know (or should know) all that already.

To me the system sounds great and I can now listen to any genre of music I want to (and I like 'em all) without feeling that I making compromises to how I like to hear my music. And yes, I like it loud.

Full disclosure: I am by no means an audiophile. I care less about the perfect rendition of ?O Isis and Osiris in Act II, Scene I of Mozart's The Magic Flute? then I do for generally good rockin' road music. After all most of what I listen to and enjoy are compressed MP3's anyway.

Again, I'm just a guy sharing his experience and trying to give something back to the community. I could not have done this without this board and the resources and information on it, so I thank you guys.

Enough yakking - on to the pics...

 

Nice job looks very clean (except the LOC installed on the under side of the rear deck, but you'll need access anyway). How is the sound over the stock setup? I am thinking of replacing the single woofer in my trunk with a more powerful dual setup - our cars have too good sound dampening in the trunk. Also, are those earthquakes you installed under the front seats?

 

Yeah, I wanted the LOC to be accessible for easy adjustments, or else I would put it behind the drivers side panel with the amps. You can only see it when you look for it. For the most part, looking into the trunk it could only be seen by kids and midgets .

The sound is much better. The combo of the Earthquakes and the subs in the trunk gives me the thump (trunk bass) and clarity (underseat subs) you expect from an upgraded system. Another note...I tested this system for a couple of days at each build point (I added the rear deck speakers first, then the trunk subs, and finally the earthquakes). If you upgrade the trunk and underseat woofers you will need to upgrade and get more power to the rear deck speakers. If not the system will sound out of balance and too sub heavy.

For comparison, my wife's car has 1800w of power going to 1 12" Alpine Type X and 100w each to 2 Infinity 6x9's and 2 Infinity 6 1/2's. This car has a split fold down seat and the bass easily gets into the cabin. In fact, you can feel the thump of the bass on the back of your head when you get into it. The BMW is a different animal, but, IMO it sounds as good as the stock setup will get (for my requirements) without getting into serious fabrication.

 

It still looks nice and I hope it performs to your liking, just another question - why no Cap? Is battery drain not a concern when using an upgraded system in our cars? I ask because that was one of the reasons I went with a single woofer in the trunk and smaller amp, so as to avoid any battery issues down the road.

 

I didn't use a cap for 3 reasons.

1- A cap is to help with sudden voltage drops that occur when the battery can't keep up with the draw caused by deep base notes. Some of this is caused by the long power runs associated with a normal install (battery in the front of the car running to amp in the rear) and the corresponding loss of voltage due to resistance and other factors (too small gauge of wire being used for example). Being that our battery is so close to the amp the run is short. I wanted to see if a cap would be necessary with this type of install, so far it hasn't been.

2- The sub amp I'm running is only 600w. In my experience a cap doesn't add much value until you get above 1000w and your find your electrical system is poor elsewhere.

3- I have HID fronts and fogs. These only pull 35w each (compared to 50 or more for the regular fog & headlights). Less pull from those means I have more headroom for current elsewhere. Most of the flickering problem back in the day was because the damn headlights pulled so much power.

I had a 2 farad cap laying around if I needed it, but so far, like I said, I haven't. With the system full blast, listening to bass heavy music and the car idling I'm showing a constant 13.8-14.2v on my voltmeter.

In my experience, there are two basic ways a battery can be damaged by a upgraded system. One, the alt is overburdened (or failing) and it can't keep up with both the system demands AND charge the battery or two, you consistently listen to music with the car off and drain the battery to the point of no return (this is what deep cycle batteries are for). In either of these cases a capacitor isn't going to help. A capacitor, IMO, is really a band aid. It hides the fact that your system is volt poor. Again IMO, you're better off upgrading your alt before using a cap. With that stated, caps are relatively inexpensive and easier to install so they do have their place. The problem is some people think caps do things they don't.

 

Good points, maybe I just need a better sub then? My amp is 600w as well (JL Audio) and the sub just doesn't seem to hit as hard as I would like.

 

You still might want to add cap or another battery.... when i had pdx 1-600 with 1 alpine type r, my fog light was flickering slightly when i didnt have extra bettery, but as soon as i got secondary battery it went away.
I like what you did except i wouldve just mount amps outside so that you can easily tune the amp if you need to... like make it mount upside down to the top of the trunk...

well you can either tune sub as you want because they might have not tune as how you like it......

 

How hard a sub hits is in direct reflection to the amount of air moved - not necessarily the wattage of the amp. If you want to "feel it" more my advice would be to add more air movement (i.e. another sub) to your configuration. Are you using a sealed or ported box? A correctly sized ported box will sound louder (more boom) than a sealed box all other things the same (however, you do give up some accuracy.)

 

Excellent write-up!

 

Wow. Awesome work!