Subwoofer - The Unofficial BMW M5 Messageboard (m5board.com)

Racin' Randy · 14th May 2002, 22:54

I just wanted to share my experience of trying to enhance the stereo in my 2000 M5. I scouted around the area and talked with about 5 different 'installers' and asked for their opinions.

What I was looking for was additional bass response expecially at low listening levels. I thought the OEM solution was very weak in that area.

Most of the installers began their speel by saying we should put a big-*** box in the trunk and take out the ski pass thru pad. NO WAY !! First of all, I have the fold down seats and I use all of the trunk on ocassion for a bicycle, and plus, I was looking for a stealth install if possible. The 2nd option was to find 2 10" free air subs and mount them where the '01-02' M Audio speakers are. This proved to be a monumental task with not many manufacturers making free-air subs anymore. I did find some, but then the amp to drive them was not only big, but expensive as well. So....grabbed an idea and measured the space available in the pull down tub on the right hand side of the trunk. There was just enough space to put a 10" sub. The trick was going to be to find a sub that needed very little cubic feet of air.

I settled on the Cerwin Vega 10" sub and an amp that would fit behind the panel on the left hand side behind the CD changer and just below the Nav system. The box was fiberglassed in for complete air tightness and a board cut to fit the front of the tub. The tub was then covered in grey carpet (albeit not a good match), and then the sub installed.

The only issue was finding the proper way to tap into the current system. Most of the inputs first tried resulted in horrible performance, but in the end the system sounds much improved and everyone that has listened to it has commented that it greatly enhanced performance. I can drive with 1/2 of the back seat down, or up, but it is a bit better with it down to allow the sound through to the front of the car.

Now, the next step is to locate some carpet (felt) that is the same color as the original BMW grey and redo the covering of the tub. Anyone have any ideas where to secure some of the stuff???

I also made the tub where it can still fold down for access to the fuses and taillamps. I also have the Ballasts behind that tub for the Bekkers taillamps.

I will take some pictures soon and see if I can figure out how to post them. Anyone wishing further info, please feel free to ask.

RR....

P.S. Dinan Stage III goes on this weekend.

BlueBomber · 14th May 2002, 23:16

Hello Randy...

Very informative write-up. I have been doing the exact same research and came up with a similar solution. I will be going with a single 12" JL audio sub. The mono amp (haven't decided which one) will be attached upside down in the space between the two stock subs. The stock subs will be disconnected.

I too did not want a large box that would what little trunk space I have (no fold down seats)!

400hpJunkie · 14th May 2002, 23:31

Had either of you considered the spare tire well? I think the air pump's pretty optional, so I think you could do a completely stealth install under there pretty easily, probably enough for at least a 10", maybe even a 12".

Are you doing sealed or ported enclosures?

CM5GO · 14th May 2002, 23:48

How did you tap into the signal without RCA outputs for your amp?

Did you use in line converters off of the speaker wire?

I have always had very bad performance from that type of rig.

I am curious because this is the only reason I havent upgraded my system.

BlueBomber · 14th May 2002, 23:50

I personally will be going with a sealed enclosure. I think putting the sub in the "wheel" is just too much work (and probably will cost more than I want to spend). Although to be honest, I haven't really looked into the wheel well option.

400hpJunkie · 15th May 2002, 00:41

Wheel well enclosures are actually pretty easy to do. For the M5, I think you'd only need to do 2 peices, a back and a top, and then seal them down and dynomat & fill the interior. You could even leave it hidden under the matt without losing too much.

I've done plenty of them in my time as an installer/owner of my own shop a long time ago. If I get some time this weekend, I'll try to put something quick together to demonstrate how to do it.

Also, if you're mounting upsidedown, take care to make sure the amp doesn't overheat. Most amps are made with the idea that the heat will rise away from the amp. Nothing a small fan can't fix.

Richard in NC · 15th May 2002, 02:04

Randy et all;
The 10in. sub in the corner sounds like a solution I heard when researching subs for my '99 540i. But I already had installed a JL mini sub (twin 8's) that was mounted behind the read seat. It sounded OK but needed the ski hole opened on my fixed rear seat to sound better. The installer had no problems tapping into the leads for the 540i premium audio subs (Nokia box standard in '00 M5s). He used some sort of line level converter and added a 150 watt amp as well. Since it was a lease vehicle, I didn't do the ski hole and eventually had the sub taken out before trading it. My M5 has the M audio option and sounds good enough to leave in place. Although, I may upgrade the door speakers.

AndyMenard · 15th May 2002, 02:43

I decided on the two sub (free-air under rear deck) approach. And it sounded GREAT!!! Installer used Dynamat between the new deck and the car's rear dash and we used 2 10" Kicker free-air subs, driven by a Precision Power 2X150 watt amp in bridged mode. He used a line level converter and also installed a gain control knob inside the car. It looked great but more importantly is sounded fantastic!! Much much better than stock. I also changed all of the interior speakers and went with MBQuart Q Series... the entire installation totally transformed the otherwise stock sound system.

Total cost (installed) including the MBQ's was around $3000.00 with $1200.00 or so being for the subs only.

Jim Catington · 15th May 2002, 02:43

I've been struggling with the same problem (lousy bass response) since I bought mine in 8/00. It seems everyone wants to cut new holes in my car to fix the problem. There seems there is no easy place to mount a sub woofer or install better woofers in place of the existing ones.

This will sound dumb, but I have gotten some substantial improvement by just increasing the fader settings more to the rear. It has boosted the level of the weak-assed woofers that came with the car. Actually had to reduce the bass setting on the tone adjustment. Like I said it is not perfect by a long shot, but it is better and I don't have any new holes in the car.

Racin' Randy · 15th May 2002, 06:54

I'll have to check with the shop to see where they ended up getting the input for the sub amp, but I will tell you that I seriously considered using the tire well, but quite frankly, that is where I store all my sh**, such as window cleaner etc. And, I didn't want to have to perforate the trunk cover, and after a recent experience with a flat tire about 200 miles from home..............well, let's just say that I didn't want to do without the pump. The M5 is my only 4 wheeled vehicle and I pretty much have to depend on it. The amp that I installed only has a gain control on the actual unit and I don't have a remote, although I have been able to do enough fine tuning through the 'tone' control settings to alter it when you get a recording that has excessive bass.

I think all these alternatives are good to learn about and I think in the end, I chose this method because when it comes time to ship the M5 off, I can easily pick up another tub and then save the speaker for another use.

I do also know that a friend of mine replaced all of the door speakers in his '01 with MB Quart and his take on the deal is that it really didn't help all that much. That is why I went the additional sub route and am very happy with the results. I was used to the stereo in a C5 Vette which has a much smaller and tighter cabin area and the bose speakers. I just wasn't happy with the 'down low' response of the stock system.

Also, I completed this deal for less than $650!