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In Reply to: More Info On Sound System Upgrades... posted by jvr on June 04, 1999 at 20:33:30:
: Folks: This can be a result of the installers personal preference as much as that of the equipment. An 8" sub may be a little small for a relatively large E34/E39, but unless it was distorting, the thin sound was probably the result of the installers preference in the set-up. This points out one of the major concerns in the final satisfaction you will have with a sound system. Make sure that your installer is willing to let you be a participant in the set-up process. Take the time to spend the final hour or so of the installation working with him/her to set up the overall balance to your taste. It'll be worth the time. : Replacing the amp in the trunk is an easy task on the E39. I foresee one MAJOR problem with this setup however: calculating and adjusting the crossover points for the factory speakers. The guy I spoke with wired his like this... : 40w to each front channel (tweet+mid+woof=1 channel) : I do not know how he did the wiring to string the tweet+mid+woof onto one amp channel. In the E39 each speaker has it's own separate channel and the amp internally crosses them over. This raises another huge question. How do the 3 individual speakers get crossed over in this setup? He didn't mention adding any crossovers. Maybe the E34 does have external crossovers, but I know the E39 does not. Neither does the E34. I assume that the installer fabricated some type of passive crossover for the task. Otherwise the tweeters would probably be blown by now. It is possible to do, but doing it to the level of a factory engineered crossover is usually beyond the level of most installers. Not because of inability, some guys out there are REALLY GOOD, but because of lack of time and/or sophisticated equipment. This can also contribute to the bright frequency balance you commented on. The tweeters and midrange drivers are a bit more sensitive than the woofers in the front, and need some attenuation at the crossover to sound balanced. Perhaps the guy is running them flat out, resulting in a treble boost. : So, I just wanted to share this information because I have not heard of anyone just replacing the amp. I'm hoping Bob Hazelwood will read this and have some comments (The guy I spoke with knew you) Kewl. Who was he? on the difficulties associated with calibrating this setup. I know you already commented on your setup and the approximate crossover frequencies used. I'd like to find out how to actually do this calibration and give this proposed setup a try. I'd hate to drop my car off and pick it up at the end of the day with the work completed. I get serious satisfaction doing this stuff myself and knowing how to tweak it is very important to me. The Nokia speakers are pretty picky when it comes to the crossover. I have only done active set ups using the factory speakers, so I am not a big help when it comes to passive crossover recommendations. I only know the starting points I would pick for the tuning process. My inclination would be to start with the following passive crossover components: Woofer: .50mH inductor in series with the positive wire. 25uF cap in series with a 4-Ohm resistor, and this combination connected in parallel to the woofer. Keep in mind that I am not saying that this is the optimum crossover. It's just the components I would pick to start the tuning process with if you like to tinker. These suggestions are simply in the ballpark, not necessarily in the right seat. BTW. For those of you intereseted in an independent test of the a/d/s/ speakers, the October 1998 issue of Car Audio and Electronics has a comparison test of the 335is against the Focal, Dynaudio and Infinity competitors. Bob Hazelwood
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: 40w to each rear channel (tweet+mid/woof=1 channel)
: 40w to sub (he has a dual voice coil sub, so it's got 2 separate stereo channels wired to it)
: Total of 6 channels on the P640 amp
Midrange: 2.5-Ohm resistor, 6.8uF cap, and .05uH inductor all in series, with the resistor first in line (closest to the amplifier) and the inductor closest to the speaker. This group in series with the midrange.
Tweeter: 2.0 Ohm resistor and 2.2uF cap in series with the tweeter.
'93 525i 5-sp. Sharked, BL/ss'd etc.
BMW CCA (Boston)
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