audio problems

Will777888 · Post by **Will777888** » Sat 17 Feb, 2007 09:33

Dear forum members,
I am having audio problems. Perhaps someone has experienced similar and could give me some advice ?
The car is a 2001 Z3 3.0. The audio is BMW Business radio cassette. The stereo powers six speakers- a pair of tweeters at the front (in the doors), a pair of woofer / mids at the front (in the footwell), and a pair of full range (!) at the rear (behind the seats). The problem is that the front mids cut out intermittently, but the front tweeters continue to ‘tweet’ as normal. In fact the front mids had been out for the last few weeks, but suddenly came back on yesterday ! They switched on and off a few times over the 1/2 hour journey. Before yesterday, the switching had been intermittent, with the off phase becoming longer and longer, until they stayed off. The rear speakers are unaffected, and like the front tweeters, have always been on. I have used the fader and balance controls to ascertain that it is definitely both front mids that are intermittent, and that they definitely are switching completely off at the same time.
The handbook for the stereo labels the connection pins on the rear. There are a pair of +/- terminals for the (4) front speakers, and a pair for the rears. I note that there is no separate tweeter output for the front pair. I assume that the front wires either:
• go direct to the mids, where the signal passes through a high pass crossover (capacitor), and thence to the tweeter, or:
• go direct to the tweeters, where the signal goes through a low pass crossover (inductor) and thence to the mids, or:
• no crossovers are involved, and the wires piggyback off the mids to the tweeters (or vice versa).
The bit that I can’t understand is: assuming the problem to be a loose connection, or a short, or a crossover breaking down, then surely the problem would only manifest on one channel ? What could possibly be switching both front mids on and off simultaneously ? Any ideas before I start to rip the dashboard apart ? Thanks.[/b]

trickyb · Post by **trickyb** » Sat 17 Feb, 2007 10:39

Will,

If the system is original, the front speakers have their own amplifier attached to the nearside front footwell speaker. It's a strange set-up, which means when/if you change the head unit, you'll invariably have to change the original speakers away from the paper cones. If both fronts are going off at the same time, it's either a feed to that amp problem, or the amp itself/

Do a quick search of the forum for 'head unit' or 'speakers' and you'll get plenty of info and pictures to help you along.

Good luck

Guest · Post by **Guest** » Sat 17 Feb, 2007 10:47

Your problem is almost certainly to do with a small amplifier that is attached to the back of the mid speaker in the passenger footwell. This amp (such as it is) has separate power and is remotely switch on from the head unit. As this fault is intermittent I suspect a loose connection or a dry joint on the circuit board. A new unit form the stealer is about £70 from memory, so its best to put out an appeal to those that have upgraded their systems.

just as an FYI. In your setup, the rear speakers and the door tweeters are powered directly from the head unit, but both footwell mid/woofers are powered from that speaker amp. That is why the mids cut out and the others don't.

Search on "footwell amp" and you will find a lot of information.

Simon

Will777888 · Post by **Will777888** » Sat 17 Feb, 2007 18:52

Thanks guys,
I'm really impressed by the knowledge base on this forum, and the willingness of people to give help. I only wish I had the knowledge to help others in return.
I suppose the extra amp on the front mids explains the better sound when faded front not rear. I had assumed that better speakers were fitted up front. What a wierd setup !
Will.

Will777888 · Post by **Will777888** » Sat 17 Feb, 2007 19:23

Have followed links. Shall probably just attempt to bypass defunct amp. Thanks a lot chaps.

Will777888 · Post by **Will777888** » Wed 07 Mar, 2007 20:31

Thanks for the advice chaps. I fixed the stereo ! I fitted a new relay from Maplin. £1.31. Beats the BMW price of >£100 for new speaker / amp assembly. The Maplin part number is JM 67.

Straight_Six · Post by **Straight_Six** » Wed 07 Mar, 2007 21:47

i too have the same problem where the footwell speakers dont work, but i have an alpine head unit so im guessing this isnt compatible for the speaker amp.

how easy is it to change the speakers? obviously ill be buying a set of door components, so ill need to replace the tweeter's and the speaker's. and ive noticed the door components im after come with crossovers! where would i stick these?

Lee

Guest · Post by **Guest** » Wed 07 Mar, 2007 21:54

Straight_Six wrote:i too have the same problem where the footwell speakers dont work, but i have an alpine head unit so im guessing this isnt compatible for the speaker amp.

how easy is it to change the speakers? obviously ill be buying a set of door components, so ill need to replace the tweeter's and the speaker's. and ive noticed the door components im after come with crossovers! where would i stick these?

Lee

its not a case of not being compatible. The footwell speakers and amp have no specific relationship to the BMW head unit. All you have to concern yourself with is that the footwell amp gets it remote turn on dignal from the head unit. Just make sure the amp remote wire on the head unit is wired into the BMW to ISO adapter. Also, the footwell amp is designed to work with a standard low power head unit, so a high power unit may over drive it somewhat.

Straight_Six · Post by **Straight_Six** » Wed 07 Mar, 2007 21:59

cheers si!

i remember not connecting my remote turn on into the bmw harness because i only used this before to power an additional amplifier (didnt realise the door speaker had an amp). i will take it out tommorow and give it a try.

can you remember which wire it needs to connect to? i know each wire has its function labelled (as you told me before).

DorsetZ3 · Post by **DorsetZ3** » Mon 02 Apr, 2007 19:27

I have the same problem (tweeters and rears working -front intermitent). I have tried Maplin for that part but it is now discontinued...

Anyone know where else to go?

Also where does this relay thing go- I only have very basic knowledge so as simple instructions as possible would be great

siwilson · Post by **siwilson** » Mon 02 Apr, 2007 20:48

The relay is actually on the amplifier circuit board. IMO its not for those that are not experienced in soldering a circuiot board.

DorsetZ3 · Post by **DorsetZ3** » Tue 03 Apr, 2007 17:56

pity - can anyone recommend anywhere - i live in dorset. Halfords are really great and have been really helpful, but am not sure they will be able to help with something like this. Really after someone to do the job quick and for a fair price - far easier if you go to somone who knows what they are doing?

any ideas?

Will777888 · Post by **Will777888** » Tue 03 Apr, 2007 20:52

As has been mentioned on other posts regarding this problem, you could always find an amp/speaker unit from a breakers.

Straight_Six · Post by **Straight_Six** » Tue 03 Apr, 2007 23:17

UPDATE!!! *** JM67X***

for anybody looking for the part number "JM 67" on maplins website, this does no longer exist... or will forgot to add an extra 'X' at the end! lol

the relay you need to search for is... JM67X

i have recieved my relay from maplin, although i dont need it now because i bypassed my amp lol!

Lee

mich · Post by **mich** » Tue 03 Apr, 2007 23:18

Will777888 wrote:Thanks guys,
I'm really impressed by the knowledge base on this forum, and the willingness of people to give help. I only wish I had the knowledge to help others in return.
I suppose the extra amp on the front mids explains the better sound when faded front not rear. I had assumed that better speakers were fitted up front. What a wierd setup !
Will.

Here is a cheap easy fix http://www.zroadster.net/forum/viewtopi ... highlight=