methodsound

Around 08+ the Individual Audio option was upgraded for the E60, it is also called the Dirac system. More info on the Dirac system can be found here. Basically the Dirac system is the top of the line for the E60. It has the same number of speakers and channels as the Logic 7 system but with a more powerful amplifier, upgraded speakers, and the Audyssey DSP. It is a very good system yet it still lacks some punch. Looking at the frequency response measurement

you can see that the EQ is smooth, and follows a very desirable curve. For those of you that don't know what they are looking at here... this graph shows the treble making it up to 10K hertz before starting the roll off. There is also a small reduction in the difficult 2-4K hertz range, and a valley in the 2-400 hertz range. Notice the bass response below 200 hertz. It does not pick up until almost the subsonic range around 30 hertz. So the bass is there, but there is no punch to it. Most listeners would prefer about a 6 db gain starting below 200 hertz.

This can be achieved by adding a subwoofer to the system to produce the punch that the under seat woofers are lacking. One thing to keep in mind is how good the soundstage of the Dirac system is. It does a very good job of placing the musicians up on stage as if they are on top of your dashboard. We could add a subwoofer in the trunk, but the goal is to keep the drummer up on stage with the rest of the band... Now I will show you a creative way to enhance the bass response in the E60 M5. The design is going to be very light weight, removable, and not take up any cargo space in the trunk.

In this car we decided not to modify the factory carpet in the firewall, but if we had, the space that is taken up by the subwoofer enclosure would be even less than what it is now... which is minimal and usually not even noticed by the passenger. I started out by masking off the whole area where I wanted to make a mold of the car.

I also used aluminum foil as a thermal and molecular barrier.

I used 7 layers of fiberglass cloth and resin to create a uniform wall thickness that is about 3/16 inch thick.

Here is what the shell looks like out of the car.

I then made a recessed baffle for the 8" subwoofer

Here is the finished enclosure with dark charcoal backed carpet

Once inside the car it is a tight fit, so the small bracket on the floor is all it takes to hold the enclosure in place

There is a small gap built into the design that allows the factory floor mat to tuck in over the top of the enclosure

The enclosure face can support the weight of your feet, and even at 6'5" tall, a passenger of my height can almost get their legs fully extended strait out even with size 13 shoes on. It really is not taking up the area your feet would normally be resting in. So that is the sacrifice, now here is the payoff...

This measurement is with the subwoofer really creating some impact in the lower end. The system also sounds very natural with the new subwoofer just blending into the system rather than being set this high. I included a bass knob for the driver to use to tune to their listening taste/ mood. For the amplifier I used and amp with built in fans, and mounted it upside down from the rear shelf

Standing back, the amplifier is barely noticable


So there you go, here is a creative way to improve the bass response in the E60s with the Individual Audio option. This is not the only way to add a subwoofer, but it is a creative solution to share with you guys that you might not have seen before

nelson29

Looks great Micheal .

Just in case you didnt know, the CIC system that was available in the 2010 models output a flat full range non equalized signal. No summing or de-eq is required.

skelevirus

sweet!! really creative!

cleung

very nice. I was wondering how the bracket is fastened to the floor?

tran23

nice location on the sub

methodsound

The bracket uses clips that go into the carpet. It is similar to the front floor mat fasteners. ( It doesn't take much to hold it in place because the enclosure was formed to the shape of the car )

cryptyk

Woo! I just wanted to chime in and say how great this turned out. I don't trust my car with anyone, but Michael treated it like his own baby. Super professional to work with, and I'm incredibly happy with the result.
I'm 6'5" and I can easily fit in the front seat with plenty of legroom. And it sounds AWESOME. I told Michael up front that I just wanted something to merge in with the low end of the Dirac system, and that's exactly what he gave me.

This guy knows the e60 inside and out.
Thanks, Michael!