Audio guys, need some help. crossover caps.

This is a front , center channel .

I just did a quick test again, wires from Amp directly to tweeter, i get sound, but not full volume ( obviously as it's just a puny tweeter )

Bottom line, not going to waste any more money on this.... time for a new center ... been wanting a B&W for a while now anyways.. :twisted:
 
You have a bad connection / component in the cross over if the tweeter lights up when you bypass it. Should be easy to find/ fix. Inductor should not go bad, and the resistors are reasonably bullet proof. There is nothing else in the circuit. Make sure you check the wires at the inner terminal connection. I have found a bunch of them hanging by a thread on older speakers.
 
speedmd said:
Sounds like a shorted cap possibly caused full range to enter and overload the tweeter. My guess. If you really like the speakers replace the driver and get rid of those electrolytic caps while your at it. If not, new reasonable sounding ones are not much more. http://www.ebay.com/itm/Polk-Audio-Monitor-30-Series-II-BLACK-Bookshelf-Speakers-NEW-PAIR-/390778296452 They have improved some also. http://hometheaterreview.com/bookshelf-speaker-reviews-wiki-information/
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SpeedMD, the non polarized caps are in fact dual back to back polarized caps... i was 5000$ high end speakers using seperate polarized caps. it work fine.

I would doubt that the tweeter would have blown due to shorted caps since it's a 12dB crossover and that there is an inductor in paralle with the tweeter, making not really possible to have low or mid freq in that tweeter. the inductor have blocked that.

Often the 12dB crossover high psss section caps blow because their tolerance is too wide and that they dont match exactly the inductor cutting frequency. so teh caps take too much current trying to push in the inductor some lower frequency. As well it work for few years but then the caps heat more and more over the use and blow.

Also it happen that they blow when the amplifier will have too much distorsion, pushing hard on the caps and speaker coils...


Doc
 
Ypedal said:
This is a front , center channel .

I just did a quick test again, wires from Amp directly to tweeter, i get sound, but not full volume ( obviously as it's just a puny tweeter )

Bottom line, not going to waste any more money on this.... time for a new center ... been wanting a B&W for a while now anyways.. :twisted:
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What is the resistance you measure on that tweetter?

a 4 ohm should measure about 3.4 ohm and a 8 ohm should measure the double. if you are close to that range your tweeter is ok.

B&W is very great high end speakers but not the same quality range as polk audio. Polk are lower quality.

You should not be disapointed with B&W !! there is some great on ebay!

Doc
 
the inductor have blocked that.
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Yes at 6db / octave. Most tweeters will overload in parallel with a big inductor if the juice is turned up to reasonably high levels. It is just a tiny tread of wire in the voice coil. I am also interested in what the resistance is showing on it. Agree, B&W is good also. I went to powered monitors on my pc. Love them.
bx5a.jpg



Nothing I have found works like a polypro or polyester cap in a 6db xover in a speaker. Some Metal foil are nice also. Not had any good luck with little can caps.
 
Ypedal said:
http://www.ebay.com/itm/B-W-Matrix-HTM-Center-Speaker-Nice-Lowest-Price-On-eBay-/121286895728?pt=Speakers_Subwoofers&hash=item1c3d432870

maybe ?
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That tweeter there would make positioning this speaker awkward would it not? For a center speaker it seems on odd choice for the to place it there given most of these sit under a tv.
Nice that one was made in England. Now they are made in china. Having said that they are made very well still.
I haven't used this exact one but have B&W speakers and have been really happy with them and cant recommend them enough.
 
Damn, I wrote it this while you posted lol
It's still interesting... I think


That resistance sounds a little low. I would of liked to of heard it. I guess it could be fried solid, so the small hf signals from the x-over can't shift it. Cooking the coil till the ferro fluid becomes treacle will stop the coil moving about so much. Making it an easier load to drive. So lower frequencies could slip through the cap. Higher one's will get through the coil. The slope would increase from 12bd, but the extra power wastage from letting more through the cap then grounding more away with the coil will be high. All power the smoked cap would have to supply.

Well.. It's an interesting story if nothing else. Can you separate the magnet from the faceplate? I don't see any screws, but do see the voice coil may of took a direct hit(or it's the lighting)

Looks like a typical 100mm faceplate with 25mm soft dome. Not a big budget build so some soft (maybe silk) dome ebay one would do. I didn't expect such low measurements, making my 1-3 estimate out a little. It's about 4khz and most tweeters this size will do that. If you wanted to fix it.

Ebay have a section devoted to loud speaker parts. I picked up both tweeters from some flagship missions (£1300) for about £10 the pair.

I'm going after morel and dynaudio stuff mainly. The missions use the car tweeter format though. The magnet within the voice coil. Tiny things compared to putting it round the outside. Perfect for a car 6x9 repair.
 
Ypedal said:
Done.. i picked up that BW from ebay. 450 Can$ with shipping etc. .. spendy.. but should last a lifetime.

8)

Anyone want to buy a cheap Polk for parts ? :p
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Nice! Id love a review once you recieve it. Audio is massively subjective so nice detailed one would be awesome. Im sure you you will wish you did this sooner once it arrives.
 
ok.. some weirdness..... or maybe it's just me being dumb... but here is the story.

I removed the tweeter from the box, and disconnected the leads.. tested resistance again and showing no resistance.. :?

tweet1.JPG

The silk dome is not sitting perfectly flush, it's slightly down on one side and up on the other.. no clue if this is normal or a sign of problems... but the 0 ohm part can't be a good thing right ?
 
Its most likely cooked rubbing or broken. The fact that you were getting lower resistance would suggest that the coils burned off some of the insulation shorting a few wraps together. The dome may have also unglued itself in some spots and it lost the coils position and rubbed the coil and unwrapped / damaged itself in the gap. The coil former ring at times separates from the dome. It is not a high end / expensive tweeter and would not be worth reworking. If your interested in finding out what went wrong, just separate the dome from the face plate (Exacto knife) frame and it will pull out with the voice coil attached after you cut the wires leading up to the coil.

If you decide to rebuild them, get a pair of tweeters that have a rear chamber so you can run a lower crossover frequency. This has been the trend and it does make a big difference in their clarity.
 
yeah.. she's fully cooked alright..

tweet3.JPG

so what would have given out first?.. the coil or the cap ? :lol:

and i'm not complaining, this poor bastard survived more parties and abuse than any speaker should ever have to... 3 amps.. beer spills.. if it could talk... ... i'd have to kill it. hmpf.
 
this poor bastard survived more parties and abuse
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I See that it lost the war. :p Hard to tell what came first. My guess is you overheated it and melted insu. and a few turns shorted together. The newer magnetic gap fluid helps prevent this. The shorted coils cascade to lower the impedance and increase current. Was the dome unstuck at all? Does the coil show rub areas? Amazingly fine wire isn't it. With its age the woofer driver foam surrounds commonly rot if they are not rubberized cloth or sturdy rubber (no cracking) types. If they are foam as they appear, they are not worth putting money into IMO. Good to steal for the winter beater car or the ebike stereo :lol:
 
Ypedal said:
speedmd said:
ebike stereo :lol:
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Ha !!.. now there's an idea !!!!! 8)
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You could play harley hog or your favorite vintage two stroke sounds! Blipping the throttle type sounds when at stop lights. :lol: or Locomotive horn sounds when someone gets too close in a car. :evil: or even cop sirens!
 
Arrived this morning !!! :p

Wanted to clean the dust out of everything and re-do all connections to every speaker in the living room.. but just had to plug it in first for a quick test !!

Sounds amazing, voices are crisp and clear, no more boxy sound a definite improvement over the old polk.

found a QC sticker inside the tweeter head, built 1997
 
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