View Full Version : How to upgrade a 540i6?

10-06-2003, 11:29 AM
Hi all. I'd like your views on what to do to upgrade my 540i6 sound system. I've got the basic, non-DSP system. I listen to Jazz, Rock and some Classical, and I prefer quality to ear-splitting volume. In particular, I'm not interested in fuzzy, non-descript thumping that can be heard two blocks away, and very much prefer a nice tight bottom. :)

I was thinking about MB quart speakers (perhaps the PCE 213), a JL Audio 500/1 and a JL Audio 10w3v2 in a separate enclosure. I'm also thinking about adding Sirius radio. My car's a 2000, so its not pre-wired.

I'd like some comments from the experts out there. Here are my specific questions:

What would I have to do if I wanted to mount a sub (or maybe two) in the rear deck in order to get fast, tight base.
Is there better value out there for the money than the MB Quarts?
What would be the best way to integrate the Sirius? (I want to keep the CD player)

10-06-2003, 09:41 PM
The good news is that nearly every possible upgrade has already been done, so very little trailblazing still needs to be done.

Subs: I have a sealed enclosure mounted in my spare tire well, but don't recommend that you go my route. PITA is the best way to describe it. Putting free air (aka infinite baffle) subs in the rear deck is a smart way to go. Any competent installer can do this. I do suggest that they mount the speakers on a board which, in turn, is mounted to the rear deck. This will significantly reduce rattles and other vibrations in the rear deck. A pair of 10" subs would be awesome. You can go as big as 13" (Focal) but I think that would be overkill unless you are a die-hard bass-head. You can also go with a sealed enclosure in the trunk. The big issue is sound propogation, or the lack thereof. Getting bass through the trunk wall is just plain hard, making you crank it louder which increases the likelihood of rattles. The ideal solution would be a cabin-mounted sealed enclosure, but there just isn't enough room, unless you wanted to place two small enclosures (for 8" subs) in the footwells for the rear passengers - that'd work great if you only rarely had rear passengers. My next install will probably have multiple smaller subs in the main cabin.

Amps: JL makes good stuff, but I'm biased. I have the 500/1 running the sub and a 300/4 running the mains. Lots of other good brands are out there, including a/d/s/, Phoenix Gold, and Xtant.

Main speakers: This is where it gets personal so please don't take anyone's advice - just go listen! I happen to think MBQs are overly bright, but others swear by them. I am more fond of a/d/s/, Diamond Audio (which I have), JL Audio, Dynaudio, Canton, and other mellower speakers. I give you these names only to help you find a good audio shop where you can compare these brands and others. Expect to pay $300 or more for a good set of 5.25" 2-ways.

Can't help with satellite radio.


10-07-2003, 05:26 AM
BillP -- Thanks a ton. :D Bright is something I would like to avoid, so I'll watch for that when I listen.

If I go the infinite baffle route, are there particular subs that I should consider, and do I need to worry about sealing the trunk somehow?

10-07-2003, 08:59 AM
The beauty of infinite baffle subs is that the area behind the sub doesn't need to be perfectly sealed.

Sealing does two things:

1. Creates pressure (positive and negative) in the sealed chamber which prevents the speaker cone from extruding more than it is rated to do (i.e. prevents it from blowing itself up)

2. Keeps the out of phase backwaves from cancelling those coming out of the front of the speaker

#1 is needed if the speaker is designed expecting such pressures but not needed (and, in fact, harmful to the sound) if the speaker is designed expecting no such pressure.

#2 is needed to keep the volume of low frequencies audible and coherent. BTW, a vented enclosure inverts the backwaves so that the resulting energy from the vent/port augments the waves coming from the front of the speaker rather than cancelling them - the science of this is tricky and extremely precise, that's why homemade sub enclosures are almost always sealed.

Furthermore, even a tiny pinhole in a sealed enclosure will completely screw up the goals of #1 but only impacts #2 by perhaps 0.01%. If your trunk isn't perfectly sealed (and it isn't and you don't want it to be for HVAC reasons), you can't use a driver designed for a sealed enclosure but a driver designed for an infinite baffle application will be fine with perhaps 1% loss of volume due to the minor amount of leakage you will inevitably have.

Sub drivers are almost always rated for specific applications (sealed, vented, bandpass, infinite baffle (or free air)) so look for that when you choose a sub. A good installer may also recommend a driver not specifically rated for infinite baffle - if you trust him, go for it. Experience is worth a lot in this area.


10-07-2003, 02:10 PM
Thanks again BillP. This is great. :D :D Exactly what I was looking for. If I understood you correctly, it sounds like I can go the rear deck route so long as I obtain a sub that was designed for an infinite baffle application and still get very satisfactory results.

Assuming my installer (me) has little experience with infinite baffle subs. Have you (or anyone else here) heard any particluar models that sound good?

10-07-2003, 04:59 PM
I have heard three subs in BMW infinite baffle installations:

* 10" M Audio subs - available from the dealer, good, but not great, they are also not cheap at ~$180 each.

* 13" Focal subs - WOW! Focal is not cheap though.

* 12" (I think) Crossfire (I think) subs in AK's car. Very good and very loud given a fairly low powered amp (120w??).

Folks may disagree with this statement, but I don't think it is nearly as important to be picky about the brand/model of sub as it is to be picky abou the brand/model of main speaker. Installation is 80% and the sub is 20%. Given that you are the installer, doh! :D