B & W Matrix 805 high frequency imbalance

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A few years ago I purchased a poorly treated pair of B & W Matrix 805 speakers to use while reconing my home mades. I was really surprised how nice they sound and image and have been using them now regularly. I notice however that one side seems to have more balanced sound in the high frequency while the other side is still clearly playing through the tweeter but not as loud or extended.
My question is whether this might be caused by a crossover problem or is it likely to be a damaged tweeter? I like building speakers from plans but am really pretty unknowledgable about the real electronics involved. Anyone have any suggestions about probing this problem?
Swap the speakers round and see if the problem follows.

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It might be that your amp is unbalanced on bias current.

Possibly a tweeter or woofer is wired out of phase or wrong polarity. Maybe a weak solder joint.

Not rocket-science, these speakers. :)


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Thanks System7. Switching the speakers was of course the first thing I did to check and I don't have a frequency or dB meter so the problem is mainly detected by ear.
You are correct of course that it could be a lose solder joint etc. Especially when you consider the fact that these were a major bargain as the original owner apparently would come home tipsy once in a while and has tipped these speakers over a few times (that's what I meant by mistreated). The midrange, however, is still really sweet. I guess it's time I took them apart and looked but thought if someone has had this problem before it would clue me into what I might look for. Thanks for the crossover diagram. I will print that out. I'm not sure what kind of capacitors were used and perhaps they need to be redone.
I think it's gotta be said that tweeters are tweeters in the end. I'd strongly suspect that one of the tweeters has got damaged.

B&W Matrix 805

I could have a whole lot of fun with your 6" kevlar speaker and some sort of replacement unit, like this 72mm SB acoustics SB29RDNC-C000-4 unit:
SB29RDNC-C000-4 :: SB Acoustics

Some sort of attenuation with cheapie wirewound resistors might be in order, but essentially doable. You might need to knock up some sort of mounting, but that's DIY.
I took the driver out and looked around at all the solder joints, applied some cleaner to the push on connectors (actually that was a surprise to me that the joints to the drivers and the crossovers were push on and not soldered). Nothing looked out of place although the crossovers were a bit loose probably from being knocked over a couple of times. So it could be the tweeter. Strangely enough this tweeter looks to be in better shape than the other so I was wondering if there is something (possibly in the crossover) that would cause it to be louder than the other one?
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Interesting that this has been resurrected. I have not fixed the problem as I got my woofers back from the homemade system and then ended up getting some Spatial Hologram M4's which I really love. It piques my interest to consider putting some other tweeters in there though since the cabinets are bit hashed up anyway. Because of that I wouldn't want to put a lot of money into the repair, so if anyone has done a simple replacement with maybe an attenuator to balance. I would be interested in what and how you did it.

I still have the tweeter pods from my 805's if you wanted to try to find a match with yours.

Send me your address in a PM and I can mail them out this week.

I LOVED my 805 matrix speakers.. Driven by my JRDG pre and amp I had no complaints what-so-ever. Had the kids not broken the snap in tab that held the tweets I would still be using them. If you still have yours then use my tweets to find a match and then re-oil the cabinets.. They are worth keeping.
The box should arrive Wednesday.

Just me but I would try to keep them original. It would be hard to improve on it without significant outlay.

The scan speak revelators and new crossovers probably cost half as mush as the original 805's. ( and I don't know that I like them any more than the originals)
I get you Troy and will try to keep them original. I may even see if I can redo the finish on them as the black finish as I said is a bit hashed up and of course with the falls they apparently took, the covers have only one or two of the couplers to keep them on the speaker. Thanks for your help and advice. You definitely rock.
It could be as simple as old dried out Ferro fluid. There are kits with instructions on how to safely lift off the dome and voice coil assembly, cleaning out the old fluid and replacing it with new fluid.

Those things being old, maybe they lost some magnet strength.

Both very good points!!! But if QC was good (which it was) they should have aged the same..

Now he has 4 tweeters to play with and hopefully he can find 2 matching.
What a nice DIYer Troy is. He was so kind to send me his pair of tweeter pods for the Matrix 805s so I could use the 4 tweeters and get a good working pair.
Of great interest, because I had some spare parts, the suspect tweeter was removed and dissembled. (Remember these were badly abused, apparently by someone who would come home a bit tipsy and knock them off their stands.) Apparently on one of those occasions this particular tweeter had the magnet in the tweeter dislodged and decentered enough to pin the diaphragm coil. I was shocked though that from what I could detect, as I did not remove the magnet, the magnet seems to be held in place only by its strong magnetic force. It seems to me then that any relatively strong jarring could similarly displace the magnet in these tweeters even off center and in this case totally pin the speaker diaphragm against the outer wall. Does anyone know if the magnet is supposed to be held by a screw or something to keep it centered? The exploded view of the tweeter shows no such thing.
One other thing, I've searched all over the internet to see if someone has the diaphragms for sale and could not find replacements so would be interested in those as well as any information on the amount of ferrofluid needed for these tweeters
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