Vista woofers replaced! Again!

Hello,

This actually should be a continuation of my previous thread: http://www.martinloganowners.com/forum/showthread.php?11303-Vista-bass-drivers-fried-again!-What-s-wrong

That's how one of old woofers looks like
The other have just slight deformation on membrane.
Both old woofers have separated inner tube(glued) to the wavy yellow fabric.

Good news is that fix was rather inexpensive and easy. The bad news: no more listening at "realistic" sound levels.

Kudos to ML for discount on woofers and for gratis PSU board to correct slight imbalance between two speakers.

Are you a heavy R&R guy? heavy metal guy? What is the DIY Pre? are you sure it dosent leak any DC? My Vista are new & I tested pushing them hard no ill effects. I am cutting off the bottom octave. Do you keep the woofers pointed directly into the sun during the day?

beek: I listen to classic, jazz and occasionally some Peter Gabriel, Bowie, Genesis etc. I have do DC offset and I do keep my speakers in shade all the time.

I'm no expert but it doesn't look like electronics issue - coils are ok and weren't fryed. It rather look like mechanical issue with driver itself.
The tube with coil should be glued to fabric membrane (as showed on photo). When it gets separated the speaker aluminum membrane gets a lot of free movement and it results in membrane deformation. Low quality glue used and high volume levels probably is a cause of driver failure. That's my diagnose. Tell me what you think.

Its just weird that two sets of woofs go?
There are too many variables to in question about on the net.
I heard a Krell int. Push some small ML's and it was incredible.
There are some real heavys out here hope they can.help out...
Bill

Hola...as being servicing speaker for over 40 years by now, I guarantee you that it is an over driven problem. Too much flame red level. On the other hand, could be a transient, a very low frequency (like a rumble turntable) in the subsonic area. You can't listen it, but sure it is there and can cause this!. Do you use a turntable?, or this was made by a cd player? Bad capacitors could produce these kind of very low frequency transient. The strange thing is that both speakers were blown at the same time. What kind of amplifier are you using with them? You can tell us more regarding the kind of music that you were listening, and what happened!... you must listen a big booooooooooommmmmmmmmmm!!!!!! to do this kind of problem. My 2cents my friends,
R.

I'm sorry... what are these "coils" you speak of? OK... sorry for the assinine comment.

The voicecoil doesn't always have to go completely bad (i.e. heat-induced warping) for physical cone damage to occur. As Roberto suggested, ULF long-throw and/or massive transients can cause deformation as well without sustained overheating of the coil. (although in all likelyhood, the coil is taking a beating).

While I agree that there are likely some QC threshold issues with these child-labor-fueled factory woofers, I don't think it's the primary cause... but it could elevate the woofer's sensitivity (i.e. increased likelyhood of damage) when driven by an unintentionally unfriendly signal.

Check for visible "breathing" of the woofers during operation... you might even try inserting some 25Hz rolloff F-Pads (inline RCA attenuators) in series with the inputs of your amp to attenuate any rogue ULF activity (this assumes the amp itself is not the perp)

OK... now I'm off to google "speaker coils"... so alien sounding

The voice coil wires seem to be cut? How can this be, assuming it wasn't done deliberately or by accident. Me thinks it could be a current issue that burned out or heated up the coil so much that its materials began to separate and wires melt. I admit this is weird indeed!

Wait I just thought of something else, may not apply.
Do you have any teenage boys that are home when you are not?
I have heard a few of these stories...