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View Full Version : Which is positive on stock speakers?



zhandax
09-21-2007, 05:38 PM
I replaced the rear stock speakers with 5.25 MB Quarts (4 ohm). When I turned on the radio, I didn't hear the rear speakers. I faded all the way rear, and I get some sound but it is not very loud and sounds tinny. My first thought is I may have the bass drivers out of phase. I used the wide connector to the wide one on the speaker (Quart usually uses the wide as ground). Does anyone know if the wide one on the car is ground?

The other possibility is I blew the amp since I did not want to pull out the seat, disconnect the battery, put the seat back in to install the speakers then pull it back out to reconnect the battery and put it back. But if that were the case, I should not hear any sound at all??

Of course this happens immediately before I leave to drive 200 miles to a football game tomorrow.

pingu
09-21-2007, 07:31 PM
It's been a while since I played with the speakers (maybe someone else has done so more recently?) but I think that the narrow terminal is negative (this sticks out in my mind as I initially assumed that the wide terminal would be negative).

Getting the terminals the wrong way round (e.g. if you had the rear speakers anti-phase to the front speakers) would knacker the deep bass but wouldn't affect the treble. If the treble is also faint then maybe you've got a bad connection. I'd be surprised if the amp blew simply by leaving it connected to the battery (and presumably in standby?) whlle connecting new speakers.

Torque
09-21-2007, 08:49 PM
i could have sworn it said on the speakers when i pulled mine out years back (at least on the tweeters in the front doors)

zhandax
09-21-2007, 09:17 PM
I looked and did not see a + or - on the stock rear 5.25s. I did discover something interesting though, I had intermittent front drivers speakers (I thought) but when I faded full front and full left, discovered that the front driver's was doing the same thing as the rear (low volume and tinny). I removed the amp and jiggled the straight in connector (which I assume is "IN") and removed the right angle connector (which I assume is "OUT") and now I have full front sound. It did not work for the back, though. I could not get the straight in connector all the way out, though. Do the clips push in or pull out? I may have made a mess trying to spread them out.

kev535i
09-21-2007, 10:58 PM
big terminal is +ive

zhandax
09-21-2007, 11:12 PM
Would you call this a teutonic faux pas? Quart makes the big one ground, and BMW makes the big one positive?

I pulled one rear speaker and switched the leads, but unfortunately, this did not get the sound back to normal. I seem to have a deeper problem. Still barely hear the tweeter, and no woofer.

pingu
09-22-2007, 05:17 AM
Maybe a faux pas on the part of Quart - all the car speakers I've ever seen (not a vast number but never Quart) also have the narrow terminal -ve, wide one +ve.

Have you tried temporarily re-connecting the old speakers to see if the treble and bass come back?

zhandax
09-22-2007, 12:54 PM
Good call, pingu. Yes, the old ones still work. And I finally found the old Quarts I pulled out of the 528 which still had the connector ends attached and realized that the + and - are on opposite sides of the speaker. As such, both lugs are the same size. There is my lesson in humility for the week. At least I fixed the problem with the front left cutting out.

I still wonder if the clips on the straight connector squeeze or pull apart. I will have to get the connector off when I install the new amp.

kev535i
09-22-2007, 07:54 PM
a simple test to check polarity of speakers is to apply a small voltage to them - use a 1.5volt battery- and touch wire to battery terminal you should see speaker cone pulse in forward direction when +ive is to +ive -- dont leave battary connected -- just a quick touch - i do this after an install just to make sure all wireing is ok