Some great questions here, and this has the makings of a great and long-lived thread if it breaks correctly.

Got it. Don't have to replace the OEM receiver, the Bus CD isn't bad, but got it. There's a guy who has a website selling custom bezels to mount aftermarket gear into the X5 dash opening. Looks great.


I would usually not use every speaker provision in the X5.

The pros and cons of the three-way BMW speaker architecture used in the E36, E46, E39, X5, etc., have been debated over and over (there's some great posts on bimmerforums about this).

Confining the discussion to the X5:

The 6.5 provision in the bottom of the door will take many (not all, but many) Euro 165mm frames. However, it's a bad place for upper midrange to try to come from. It's low in the door, and the seats in the X are tall - but also, speakers have a performance phenomenon called "beaming" - as they play higher and higher notes, their off-axis performance gets worse and worse, or, stated another way, their output gets narrower and narrower like a flashlight beam. This is a physics law that is governed by the diameter of the driver and the frequencies being played - you can't design it out. You can make it less objectionable by designing a woofer with a rising response at the top end - but all the response curves I've ever seen for speakers that do this show a ragged response curve up there.

So BMW's response was to install a cone mid in the top of the dash and a tweeter playing only very high notes in the inboard part of the side mirror sail.

The cone mid they use is not anything that is used by mainstream suppliers and is almost impossible to replace directly.

On top of that, any three-way woofer/mid/tweeter system becomes complicated with relative loudnesses and what not. The DSP amp has specific output channels for each driver, with each one tuned to a specific output level (edited to add: for the impedance and efficiency of the OEM driver, AND only playing a narrow band of notes for that specific driver).

If you DID put together a midwoofer/midrange/tweeter combo that fit into the locations, you would need to address the physical disparity of the various drivers. It would be sily to expect most passive crossover designers to have expected this configuration. The best results would be obtained by using dedicated channels for the midwoofers and the mids and tweeters - but that's not cheap.

What we've done in the X5 and in other BMWs is to use a soft-dome tweeter that plays low into the upper midrange, and position it in the dash, and leave out the side tweeters entirely (the BMW tweeter is very small and it's very hard to get good aftermarket tweeters in there). This then allows use of a 165mm midwoofer that is not explected to handle as much of that midrange vocal/horn/string detail. Simpler setup, but using far better components. I recommend a crossover freq of 1800 to 3000, and components that work well in this config include Dynaudio, DLS, Morel, Hertz of Italy, and a few others.

When you use MBQuart or Focal or some others with high crossover points, you get a hole in the midrange in the X5 that leaves out a lot of detail.




If you would let me I would not wire the rear speakers. Rear speakers diffuse the stereo image, which in the above scenario would be in the windshield most of the time, and since your right ear has a clear shot at the passenger rear door, the front stage effect would be ruined.

But if you strenuously objected and just had to have rear speakers, I would use a really good point-source speaker and leave the top mid holes in the door unused. The Morel Integra 6 is the finest automotive coaxial available and that's what I would use if we could afford $400 for the speaker and another $200-350 or so for additional amplifier channels.

Short of that, DLS, Hertz, and Morel maoe good $150-$200 coaxials. I would avoid the components to A) lowerthe tweeter, and B) save money for the front components, which are FAR more important from a sound quality point of view.


Not sure what you mean here, but in a sense, we would. Whenever tweeters and midwoofers are used with passive crossovers, they are technically in parallel from a wiring point of view, but not from an impedance overlay point of view - the job of the passive crossover is to prevent these speakers from being seen as a parallel load on common frequencies. That probably made no sense, don't worry about it.


OK, here we go.

HU - if it's OEM, the balanced outputs from the aft-mounted tuner module go into a balanced-compatible amplifier, OR a balanced adapter (some LOCs do this, the Zapco BTL does this), OR into a Jensen Transformers Iso-Max isolator.

From there we would go into either a 3,4,5, or 6-channel amp, or two amps. I would choose amps that will fit under the load floor (is yours the sliding or the lift-out?) and probably that have fan cooling if possible.

The output of the fronts would go to a passive crossover that is also in the back area, the outputs of those would go to the tweeter and door woofer wires. Door mid wires are unused.

Then I would use as robust a 6.5 as would readily go in the front door. For example, the Dynaudio MW160 woofer is a lot of work to install, the MW160GT is not very much work to install. Does the non-GT sound better than the GT? Maybe a little, I don't know, but it's not worth the work in my opinion - the GT sounds great.

If you are going with the tweeter in the top of the dash, almost everything fits. The huge Scan-Speak Alpine F1 and the Dyne Esotar and the Morel Supremo don't fit, but darn near everything else does.

The actual architecture is a function of budget. At $2K installed, my choices are very different than they are at $5K installed. At the lower prices, I might suggest robust 6.5s all round and no subwoofer.

If you were a client of ours, I would ask for you to decide on rears, on budget, and on the HU. I personally think that I can get the X to sound damn good with the Business CD.

Here's one we did (the amps have since been replaced)
http://www.xoutpost.com/stereo-system...005-4-8is.html

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