Custom Subwoofer Enclosure and Amp Installed

[carlgo]

Wow, years and years ago I did the Essam version and contributed some to the thread, and I return to the forum and it is still a hot subject, with different versions and 32,000 hits!

BTW, mine is still going strong. Cut a hole in the trim panel and installed a grill so it looks stock. Frankly I wouldn't worry too much about tiny differences in volume as I doubt you could hear the dif, but some of the new boxes look very nice indeed and so why not.

Mine was also updated with new speakers so it is vastly better than the awful original.

[X5Boise]

Originally Posted by carlgo

Mine was also updated with new speakers so it is vastly better than the awful original.

Just curious, which subwoofer did you use and what are you using now? Thanks.

[X5Boise]

Finally got around to try to install the amplifier and to my dismay, the Alpine MRP-M500 amplifier doesn't fit in the floor space by the L side of the spare tire and access panel. Some other folks got it to fit, but I think with my nav, CD changer, and iBus controller, the current space is about 1/8" a bit too tight in depth and I don't feel like grinding any part of the unibody down. Will have to wait a few more days to get a new amp: probably a Kenwood X500-1 (7 3/8" depth) or MTX TD500.1D (5 9/16" depth) (both 300W RMS x 4ohms). Both will easily fit in the space (measured 3x to make sure).

Nonetheless, the subwoofer and amp wiring all installed and ready to go...

[X5Boise]

Since I'm waiting for my new amplifier, I thought I'd spend some time modifying the rear cargo cover. I used a 10" metal mesh two-piece cover from eBay ($16 shipped)--the inner piece is a metal ring (about 1/2" deep lip) with mounting holes for screws/bolts, the outer piece is the metal mesh that snaps in place.

I measured where the subwoofer would go on the rear cover, then used the inner metal mounting ring to estimate where to cut the plastic cover. The inner side of the rear cover has a deep pile carpeting which can be lifted from the "mushroom" rivets to reveal the inner plastic cover. An angle grinder was then used to cut the new hole in the cargo cover. The deep plush carpeting was cut with a basic utility knife to reveal the speaker.




The metal inner ring was mounted with #8 bolts (3/4" length; round bolt side facing the speakers) and the accompanying nuts (both were purchased at Home Depot). The included screws that came with the speaker cover were too long and the locking metal tabs were designed to be unsuable for this particular application. I used a medium threadlock on there so the nuts wouldn't work loose over time. After that, I just snapped the outside mesh cover in place--looks factory clean and stealthy and the cargo area is still fully usable (see photo).



If you desire more "stealth", from the cut-out circular deep pile inner carpeting, you can peel a thin layer off of it, and get a 10" piece portion to stay just inside the mesh cover so that the PIONEER logo doesn't show through. Alternatively, you could use a very thin pieice of black cloth to wedge in place as well (to hide whatever speaker you may have behind the speaker grill mesh).

Now I just need the smaller footprint amp (Kenwood X500-1) to get here so I can finally get the missing bass from the factory setup and put the project to rest.

Again, thanks to all of those before who lead the groundwork on this project to make this a relatively easy task.

[aimtimes100]

wondering how the OP setup is holding up.i placed the amp in the same location as his and there was an interference of some sort.constant static noise and when i moved the aftermarket amp it was fine

[nigwhyrito]

I mounted my Alpine mrp m850 under the spare tire. its been going strong for over a year. I also have the sliding floor so it made my install even harder. but the spare tire fits in just the same and my amp has not overheated yet. this includes 5 and 6 hour drives to sc and NJ. I just pushed the amp as far as I could towards the front of the vehicle and dropped the spare tire over it. The tire sits a little bit crooked but once i put the put the removable black cover on its in there and everything opens and closes correctly. Those alpine Mrp m series amps were made well. I never seen a post about them getting hot.

[aimtimes100]

interesting choice.i was thinking of mounting on the panel so that it fits on the backside of it where the 2nd set of fuses are but wasn't sure how practical it was due to over heating.i suspect my amp just over heated so many times it finally just shut down.so your amp fit between the battery and the vertically mounted green box under the floor?

[nigwhyrito]

ill get you some pics today.. its too early for me to go outside right now.
Im checking my harddrive now to see if i have any install pics too.

[X5Boise]

I spent my afternoon installing the smaller Kenwood X500-1 (300W RMS mono) amplifier along with the Stinger SGN12 line output converter (requires splicing into the factory amp wiring--which is relatively simple to do), and I must say that adding a 10" subwoofer helps out with adding in the missing bottom-end that my E53 has sorely been missing. While not windows shattering bass, which I did not want from the getgo, listening to music in the car is actually quite enjoyable again.

I had upgraded my tweeters, mids, and midbass from BSW, and I thought they were a good upgrade for cleaner sound than the stock speakers. However, the midbass speakers didn't do much for bass (no improvement over the stock speakers, except for better clarity), so I ended up with building the subwoofer box that originated with Zerochief (mostly), Essam, and a few others.

The smaller Kenwood X500-1 fit in the place that my original Alpine MRP-M500 amplifier could not fit in before. I have nav, non-DSP 10 speaker radio, and a CD changer in my 2005 X5 4.4i, and with the iBus module in the same rear cargo area, it was hard to fit the Alpine amp in place (1/8" too deep). The low footprint Kenwood fits great with room to spare on 1/2" MDF mounting plate I made (see picture). This MDF plate stablizes and firmly holds the amp in place so it doesn't rattle in the trunk nor short something out.



The amp was rotated so only the low level inputs faced the spare tire (easier to remove the spare tire by a quick disconnect of the cable), and allowed me to be able to easily access and adjust the amp settings, and lastly, made for a cleaner look (hides the bulky ground, remote, power inputs and speaker outputs).



In any event, I'm extremely happy with the subwoofer addition, and once I get a bit more tweaking on the gain, crossover, and bass boost over the next few days, it should dialed in. A hint for folks who may be tuning the subwoofer--once you put in the carpeted rear cargo floor, it will attenuate your bass a bit. I tried tuning without it in place and thought I had it right where I wanted it, but once I put in the carpeted rear cargo floor, I had to turn up the gain a bit to compensate for the damping. For reference, my Kenwood settings (per my preferences and my subwoofer box): bass boost: +3db (@ 40Hz), low pass crossover: ~90 Hz), and input sensitivity (~1.6 volts)--subject to change over the next few days as I tweak the sound a little more.

Enjoy!

[X5Boise]

After driving around a few more days, here are my updated Kenwood X500-1 amplifier settings (based on my custom box and the Stinger SGN12 line output converter)--may help others tune their system:

• Bass boost: +1db (@ 40Hz) [previously was set too high and bass sounded muddled]
• Low pass crossover: ~80 Hz [near where the midbass speakers cutoff]
• Input sensitivity (~1.0 volts)

Nice clean sound without sounding overly harsh or synthetic. Again, just my baseline settings for my particular setup to help others that may want to tune their setup. Nonetheless, everyone will have their own preferences.

================


Also, as a reference to tap the Stinger SGN12 (or any line output converter; or directly to the aftermarket subwoofer amp if it has speaker level inputs) off the factory BMW amplier harness wiring, here are my notes. Again, this is for a 10 speaker, premium, non-DSP system--if you have a 6 speaker or DSP system, these notes won't pertain to you:


2 subconnectors on the main BMW amplifier wiring harness: a grey subconnector and a black subconnector.


GREY SUBCONNECTOR
White (plain white): remote on lead [near the back 2/3rds of the grey connector]
Twisted pair #1: Blue with black stripe (+) // Brown with Orange Stripe (-) [midbass, rear door speaker tap; one side (can't remember if the L or R side)]

BLACK SUBCONNECTOR
Twisted pair #2: Yellow with black stripe (+) // Brown with Orange Stripe (-) [midbass, rear door speaker tap; other side from above]

I used butt connectors to splice the factory amplifier harness wiring with the Stinger line output connector. There are other methods you can use as well. From there, you hook up the line output converter RCA jacks and the tapped remote on lead to your added-on aftermarket subwoofer amp, and you should be good to go.

Good luck with the install. You'll enjoy your car's stereo that much more!