help me diagnose speaker-failure!
 

Hi guys, I have come across a loudspeaker problem and thought that experienced loudspeaker-builders like you could maybe figure out what is wrong! any help would be highly appreciated!

the problem:
I bought a pair of speakers (Dynaudio M2, passive) and had the previous owner send them to me through UPS. They arrived without any drivers/cones pushed in, but I could see that they were treated pretty rough, the dampening material inside came down, the shipping-boxes were pretty **** and UPS did not care at all about the "this side up" signs.

Anyway, set them up, connected them and found that one tweeter was not playing back any sound. The second thing I found was that this speaker, though correctly connected) was out of phase with the other one.

So my guess is that through the handling maybe an internal connection has gotten disconnected. But what about the out of phase thing? can a loose connection inside reverse the phase of a speaker?

If you have any theories what happened inside these beauties, please let me know!

Thanks a lot,
Patrick

Generally no a loose connection cannot alter the phase completely of the whole speaker, which is what you are saying I think.

In some instances if a shunt component became disconnected it could alter the phase such that now you get a sizable notch at the xover frequency, thats not whats happening here though.

I once had a pair of loudspeakers that were wired differently to each other, one needed to be wired black to red and the other black to black, strange. But this could have happened here.

The previous owner might have opened them up and gone poking around with a soldering iron and soldered the bass drivers wires back on the wrong way round.

The tweeter not working could simply be a loose connection or a problem with the tweeter itsself. There is a chance that in transit a large knock to the speakers caused the voice coil of the tweeter to become misaligned such that its now unable to move freely in the gap. If you have a multimeter I would suggest putting it into AC mode and just playing some music thru the speakers and place the meters probes on the tweeters terminals. Although most cheap meters are meant to work well at single freqeucies it shoud be sufficient to see if there is any signal getting through.

:captain:

WildCowboys: Please do not try to get around the autocensor again. I had to go in and manually do it, and extra work like that makes me grumpy.

thanks for the input 5th! I will try to investigate further what happened....

sorry sy, I did absolutely not know that the auto-censor reacts to stuff like totally incorrectly spelled profanity. amuses me, but of course I won´t do it again!

regards,
pat

Pat,

I can empathize with you on the damage to your speakers. The last set of tweeters that came to me in the mail should have read "don't bounce these like a basketball". They have now been reassigned to holding the monthly bills on the fridge door. ;)

I think what Mr. Y was saying (S.Y. are his initials) is that he had to go and fix it manually because the auto sensor didn't catch it and profanity is shunned on this site. It's not needed to make your point, even though it feels good to vent sometimes.

Good luck with the speakers, let us know what you find.

Cheers,
Cal

Sounds like you should be billing UPS for damages to me...

l try to get something from ups but I doubt that they will pay for an internal damage! the only real sign for rough handling is that the dampening material came down and is now almost falling out of the bassreflex-ports...


rock on,
pat

Surely the sign of rough handling is the fact that the product you bought is non functional! most probably due to UPS delivery.

yeah but UPS will say the seller sent me broken stuff and that they are ok outside so I have no proof of shipping-damage! don´t you think? to me the dampening material is the only proof. this does not happen at home or in a studio, only through rough shipping!

It seems like an stupid state of affairs to me. To maintain custormer satisfaction and to make you feel confortable using UPS again, you would think they would want to give you the money for damaged goods. Unfortunately thats not how the world works, ok in some parts it does but most no.

Lets hope you can locate the fault.