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Discussion Starter · #1 ·
Hi, just bought a 2000 z3 with HK system. Subwoofer was blown so i bought a new speaker. Still didn't work. Bought a used HK amp for the subwoofer. Still no sound.....help? Checked wires and they appear to be ok. All other speakers work fine! Frustrated...
 

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It sounds like you've checked all of the easy stuff. Of course it's quite possible that it's in the head unit, or that you replaced parts with defective parts. If the head unit has been replaced, it could be mis-wired. It could be broken wiring, but that's fairly rare.

It's time for some serious diagnosis. There are plenty of HK Stereo wiring diagrams on the net, Bentley manuals, in this forum, and elsewhere. Identfy the paths of the subwoofer signals. I would get a known-good amplifier such as a guitar amp, stereo amp, or car amp and start tracing the signals. Is it coming out of the head unit? Going into the HK amp? Out of the HK amp? Into the subwoofer? etc. I assume you are aware that there are two amplifiers for your HK system; the subwoofer amp is on the driver's side of the trunk. Older HK systems have only one.

Of course, most people will recommend discarding the HK amp (which has an amazing 10% total harmonic distortion) for a real audio amp. If you have the original head unit, it might be time to move up from cassette tapes. Then the speakers were pretty poor when new, and have only gotten worse. In short, this might not be worth spending much time on.
 

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Discussion Starter · #3 ·
Hi Blacklane, thanks for your advice. took the car into a car audio place. bought a kenwood stereo and connected a kicker 6.5" subwoofer thru existing amp. Now, we have the opposite problem! cannot independently control the subwoofer and it drowns out all the other speakers. They suggested maybe connecting an RCA or perhaps another amp. I'm thinking another amp. Any recommendations for an aftermarket amp that goes from a Kenwood head unit to one 6.5" kicker subwoofer? Thanks
 

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I'm in the middle of a complete stereo upgrade, so I don't have any results yet. Lots of people run RCA cables from the head unit to an amplifier in the trunk. That's what I am doing and I can say it's not for the faint of heart. You start by removing the seats to simplify things, then the roll hoops, subwoofer enclosure, back carpeting, trunk carpeting, glove box, and finally center console. Now you're ready to run the wires inside the console, around the roll hoops, and down into the trunk on the passenger side.

Luckily I had my folding top off, which greatly improved access as well. I was even able to weld some nuts to the front trunk wall to mount the amp. Not many people have that opportunity, although there are some nuts already welded to the trunk wall on the driver's side that you may be able to use.

Do a search in this forum on "stereo amp." You will get over 100 hits on different approaches and solutions. One good one is here:
http://www.bimmerfest.com/forums/showthread.php?t=542006&highlight=stereo+amp
 

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Discussion Starter · #5 ·
OK, i'll just try replacing the amp with a 50 x 2 that should be good to power a kicker 6.5" subwoofer.....good luck my friend....i do not envy you....better think about any other things you might want to do to the car (i.e. ejection seats) now that you have it apart!
 

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A couple months ago I replaced the head unit in the 2001 and installed Boston Acoustics speakers up front and behind the seats, both are driven from the head unit. The sub and stock amps are out of the system. An improvement over stock but still nothing to write home about. As you would expect really missing the low end.

I've just started work on the 2000. I've just installed identical Boston Acoustics up front and behind the seats. I have a Kicker on order to go into the stock sub enclosure and will power them with a Alpine 5 channel amp fed by the stock head unit. I'll post once I have some results but it sounds like you will be a week ahead of me.
 

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Discussion Starter · #7 ·
Hey Dane,
I finally take the car into an audio place and they recommend changing the head unit. Bought a kenwood and they connected it up....still no sound! The stock HK amp is fine. The head unit is new and the subwoofer speaker is new. They tap into the rear speaker wires and run it thru the amp and we get sound......the only problem is that the subwoofer drowns out all other speakers. They are now recommending RCAs out of head unit to control the amp or possibly an after market amp like a 50 x 2 to drive the subwoofer....

Why can't anyone fix this? so frustrated but will keep on trying!
 

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I have the door, kick panel and behind the seat speakers installed, the amp just arrived today and I got notice that the subwoofer shipped today. So, by next week I should have the amplifier and sub amplifier out of the car and available if you need them.

If you end up going with an aftermarket amp I'm putting in a Alpine MRX-V60 which is a five channel. It was less than $300 with shipping and allows me to take both BMW HK amps out of the car.
 

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Discussion Starter · #9 ·
Thanks! I think im ok for now...gonna see if i can get back to the audio place next week to follow up. been looking for headliner rivets which attach the headliner to the convertible top. I think it may be an aftermarket product. They are coming loose and the headlner is falling around the back window.

Good luck to you!
 

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I now have two Z's (ok, one Z and one M) side by side with similar but different stereo's. The black car has a Kenwood head unit driving two way Boston Acoustic (BA) component speakers (bas/mid in kick and tweets in the door) with BA two way's behind the seats. The subwoofer and both BMW HK amplifiers have been removed. It sounds good, better than original with a much brighter sound though lacking in low end thump. It plays clean and solid up to mid/moderate volume levels but it does noticeably distort if you turn it up to teenager levels.

Next to it I have the blue car with the factory head unit driving a Alpine amp and the same exact BA speakers as the black car. At normal volume levels it is difficult to detect a difference in sound. The system with the amp though can play much louder with nice clean sound. Once the subwoofer arrives on Monday I think it will give the edge to the system in the blue car but I still don't expect serious bass.
 

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Last week I finished the work on the blue car. I have to say I think it is how the car should have sounded when new. The locations of the speakers is not perfect so I find the BA tweeters a bit bright but easy to bring in-line with the treble control. The bass from the 6" kicker is... I'm torn between saying "good" and "I'm surprised". At it's worst it is much better than the stock sub. I don't know if it is the speaker or the amplifier. It does not have the car rattling thud needed to gain respect in the hood but it is very capable of easily playing my tunes over highway & wind noise with noticeable bass . I should have done this modification 6 years ago when I bought the car.

I am quite pleased with the quality of sound from the stock head unit. For the life of me I cannot figure out why BMW put those two crappy amps behind it.
 
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