I've done a couple of audio upgrades in X3s. We specialize in invisible, non-invasive, and musical installs. No "Pimp My Ride", no thump.
Well, we recently did the most complex sound system in an X3 so far, and it's still pretty darned invisible, and it sounds great.
We retained the factory HU. The non-DSP X3s have full-range, non-equalized balanced preamp outputs to the amp from the HU. These outputs are sensitive to loading and can go into high-current protection shutdown with many OEM interface methods.
Do it right, and it works great. I've learned from experience with other X3s how to make this work.
The system diagram;
We installed the following:
- Morel Hybrid Ovation 4 components in the front doors (bi-amplified). These have a 28mm silk tweeter that plays down to 1800 Hz, a 2" motor coil, and neodymium magnets on the mid for small size. I played these 4" mids very low and it worked very well. (I also damped the backs of the doors ).
- Morel Integra Ovation point-source speakers in the rear doors (using passive crossovers)
- A flat 8" woofer in the rear (more on this later).
We also amplified the OEM underseat 6's as midbass speakers.
We used Zapco amps because they work great, they sound amazing, and they have true balanced inputs, which work great with the X3 HU when interfaced properly.
- A Zapco DC360 4-channel amp in the floor (Sub and midbass).
- A Zapco DC360 4-channel amp in the driver's side panel (F mids and F tweets).
- A Zapco DC200 2-channel amp in the driver's side panel (Rear coaxes).
For these amps to fit we modded the pocket - we made it shallower:
To run this many inputs off of the F output of the BMW HU, we used a Zapco Symbilink line driver as a buffer amp.
One reason we were using so many channels is because the client wanted time correction for each of the drivers. The DC amps have DSP functions built in. Each front driver, the rear point-source drivers, and the sub are all arriving at the driver's head in perfect alignment. When you play the test disc track witha voice at "left - left center - center - right center - right", the vocals are perfectly palced, and then when you play misc, it's amazing to see how much location information there was in the recording that really IS audible in a car. In short, amazing imaging.
We know that that doesn't work well for a front-seat passenger, so we installed a Zapco DRC controller in the center console. This has 5 presets for easy control of the amplifier's DSP functions - time alignment, crossover, gain, and equalization. The system is programmed for driver's seat time corrected and non-time corrected presets. The DRC color is programmed to matche the BMW illumination.
Now, the MB Quart RUA-210 is the only speaker I've found that can be dropped into the X3 due to depth limits. However, that speaker just wasn't going to cut it for this client - it's not that great a speaker.
If you remove the door panels and take off the grilles, you can mod the front of the door panel behind the grille by cutting a slightly larger hole in it - exposing the black plastic plate behind it. Then you can front load the Morel woofer.
Then you take the metal mesh off of the plastic frame it's wrapped around. There is a sheet of black cheesecloth behind the mesh, and a layer of foam behind the cloth. Cut the foam away from the tweeter and mid holes (yes, the BMW tweeters have a 1/8" foam sheet over them!) and then cut a larger hole in the black grille frame that will accomodate the frame OD of the Morel driver.
Then glue the frame back on the door panel. Repeat three more times. Lots of work but it works MARVELOUSLY ! The Morels do NOT hit the back of the grille, either. Tested with a 14VDC Makita battery.
I attribute the image height to the high position of the mid and tweet in the doors. The midbass is not bad, much better than stock, but I'm concerned about blowing an OEM woofer so I don't drive those underseat speakers as hard as I could. With any kind of acoustic music, the drums are solidly in front of the listener.
On the woofer, I usually use an Avincar 8" I get from an OEM maker. very shallow, very musical, works in 0.3 cf. But this client had 80% rap songs on his iPod. I was worried about output. So I tested and used a Pioneer flat 8" woofer. It had that peak that rap music often wants, and was better for that than my 8" is. If I had to do it again, for this kind of music (which is NOT my specilty) I would use a flat 10", I think... but I didn't have room for a bigger amp - this 8" is running on only 180W!
We also have made the woofer enclosure in the past very thin, and left the corner pocket usable. In this case, we made it larger, for more low-end thump - not my speed, but something I felt was a good call in the circumstances. I was very pleased with the match on the upholstery.
System sounded great, imaging was amazing, not a hint of engine noise, and looks stock!