Re: MB Quart drop in speakers (more) (archive)

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The MB Quart set that is the drop in replacement for the E36 is the QM 325.20/.21. This set consists of a 4inch coaxial for the door and a 5 1/4 inch for the kick panel. The kit also includes a mounting adaptor and grill for the the door speakers, which is required since the factory grills are part of the drivers. The MB Quart drop-in set uses a coax for the door because E36s without premium sound only had one pair of speakers in the doors.

The RSB 325 is a generic 3 way set (generic meaning not for a particular make/model). However, the mounting kit for the E36 door speakers in the QM 325.20/.21 set can be used with any of the MB quart 4inch drivers and can be ordered separately through your local MB Quart dealer. So, assuming the outer diameter of the tweeter is the same as the factory tweeter hole, the 3 way set can be a drop-in replacement with the addition of the 4inch mounting adaptors if you have separate tweeter and mid holes in your doors. The RSB 325 set comes with the Musicomp crossovers which are bigger and have different wiring options like bi-wire and bi-amp. Bi-amping allows you to use separate amp channels for the doors and the kick panels. Using seperate channels allows you to better balance the levels between the doors and the kick panels. I am not sure of the retail price of either set. I think the RSB 325 set has been superceded.

Since, the listener is positioned closer to one side in an automobile the sound from the speaker closest to the listener will arrive before the sound from the other side. This screws up imaging.
In the quest for perfect imaging, the pros have discovered that placing the speakers as far as possible from the listeners ears will minimize the difference in the distance the sound travels from the left and right speakers to the listener.
Therefore, the "pros" will fabricate custom kickpanels which position the speakers for optimum imaging. In the E36, the kick panel locations are tucked way up under the dash so mounting a set of coaxials there will not yield very good sound since the dash blocks the tweeters. The disadvantages of custom kick panels are they are expensive, and on the drivers side you will lose the dead pedal, which I find useful in "spirited" driving. They also make it obvious to theives that you have an expensive audio system.

If you use a three-way set the factory locations in the E36 are not that bad. If you use a two way set, with a high crossover frequency the distance between the tweeter and mid will be too great and the set will not sound right. Even with the a/d/s/ sets which have a lower crossover frequency to allow them to be farther apart, it will sound like there is a gap in the midrange response because the mids are so far under the dash. Adding a 4 inch mid in the door fills in the midrange nicely. This will allow an even lower crossover frequency between the doors and the kick panels, which minimizes the effects of the distance between the drivers. Now the kick panels will be reproducing only the lower less directional frequencies.

One last bit of advice on speakers: I highly recommend listening to any speakers especially MB Quarts. Some people find the tweeters to be very bright and painful at high volumes, especially the older titanium dome tweeters. Speaker designers have since refined the titanium dome tweeter so they aren't that bad. Some people actually like them. I don't know anything about your hearing or your taste in music so my only recommendation is to listen before you dish out your hard earned cash.

: Okay, since I've already seen more than a few messages about MB Quart speakers. I guess I'll just jump in the bandwagon and ask some more questions myself. Stereo gurus, your help is greatly appreciated.
: Here're the questions, I know there's the so-called "drop-in" component speaker system made for the E36 3 series, but is it the QM 325.20/21 model? Or the RSB 325? I've seen another guy advertising a set of RSB 325 3-way component speakers as the drop-in replacement speakers for E36 3 series. What gives? Which is the actual direct drop-in model anyway? It seems to be that RSB 325 appears to be more like the direct drop-in replacement speakers since it has the tweeter, mid, and the woofer, versus the QM 325, which only has a mid (with a built in tweeter) and a woofer. How does the QM 325 compare to the RSB 325 component speakers? Does anyone know the retail price for each set?
: Lastly, I've seen many stereo pros opting for MB Quart speakers that only go in the kick panels. They simply disconnect and leave the stock mids and tweets untouched. My question is, if MB Quart's made drop-in replacement speakers for the E36 3 series already, why bother to go thru all the troubles of modifying the kickpanels? Is it actually a better choice over the drop-in way?
: Any inputs? Suggestions? Ideas?
: Sorry to have so many questions.

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