KEF Q150 total blowout (literally)

[Frugal]

A friend told me that he thought he may have blown his speaker. This is what I found under the grill. Never seen this before!
Pioneer SC 67 running one pair of KEF Q150. Not looking for advice, just wanted to share.

 

[Phase 2]

Damm the bad luck!

 

[Beave]

Looks like Q100s, not Q150s.

I've seen a few (maybe 2 or 3) pics online before of people doing that to their Q100s or Q300s when overdriving the midwoofer.

 

[davidscott]

Wow never saw anything like that before without some actual physical damage to the driver.

 

[Russdawg1]

Are you sure your friend didn’t blow them by stabbing them with a knife instead? I’ve never seen a cone explode like that. Usually a “blown” woofer means the voice coil has been fried or separated from the rest of the woofer

 

[Beave]

Do a Google image search and you'll see a couple of other KEFs with very similar damage. When that thin aluminum cone exceeds its 'safe' range of motion, it bends and cracks.

 

[killdozzer]

Hurts my eyes and soul. Such waste...

 

[ryanosaur]

Wow. Strangely fascinated by this.
On one hand, I feel for your friend. My KEF audition was cool... great sounding speakers. Wouldn't wish that on anybody.
On the other hand, the part of me that got listening fatigue during that same audition is jumping with glee.


My guess is the speaker was suicidal for being put on its side in a cabinet. That should be a crime.

 

[ichigo]

Looks scary...I think I'll stick to 3 way coaxial with a sub to avoid this...

 

[tyhjaarpa]

Are you sure your friend didn’t blow them by stabbing them with a knife instead? I’ve never seen a cone explode like that. Usually a “blown” woofer means the voice coil has been fried or separated from the rest of the woofer

These are not typical speaker elements as they have basicly two elements in one.

I would assume he has blasted those speakers really loud and possibly over driven amp to cause massive clipping.

 

[Kvn_Walker]

Looks like he bought the wrong tool for the job. Must have been playing them very loud and possibly full range to boot (or crossed over lower than a 5" speaker should ever be).

 

[<eargiant]

Doesn't surprise me. Even my LS50 which I assume have better drivers couldn't take a clean full range signal at anything approaching ~90dB in a small room. Thap, thap, thap.

 

[KenM10759]

Was that 90dB measured from a listening position or the standard 1 meter? My LS50's don't have any distortion like that at -90dB from my 1 meter away listening position.

 

[<eargiant]

Was that 90dB measured from a listening position or the standard 1 meter? My LS50's don't have any distortion like that at -90dB from my 1 meter away listening position.

From the listening position ~ 8' away. I discussed my experience in the thread linked below starting on post #46.

https://forums.audioholics.com/forums/threads/legacy-studio-hd-vs-kef-ls50.111132/page-3

 

[GrimSurfer]

LOL. So that's what they mean by "sound breaking up" at the edge of a cone!

For aluminum to fracture like that means that it is either a special alloy or was heated treated for stiffness (or both).

 

[<eargiant]

LOL. So that's what they mean by "sound breaking up" at the edge of a cone!

For aluminum to fracture like that means that it is either a special alloy or was heated treated for stiffness (or both).

If I saw that picture in isolation and not with the background the OP provided I would've never thought that extensive damage like that could have been caused by being overdriven. It actually looks like it incurred extreme physical damage, like getting kicked with a boot .

 

[lovinthehd]

Hurts my eyes and soul. Such waste...

Didn't you have KEF LS50 cone damage from handling/contact?

 

[killdozzer]

Didn't you have KEF LS50 cone damage from handling/contact?

Indeed. That's why I relate with the guy. But my damage was almost non-existent. I managed to straighten it out easily.

Trying to see something positive in the whole story, I thought to myself; this was the only way to learn just how soft the membranes are. Being used to paper cones, I might have done far more damage just trying to clean them. (remember; the damage was done with a slightest of flicks of my hand holding a glasses cleaning cloth in an attempt to dust them of - one uncontrolled flick and I touched the membrane).

I said back then; I appreciate these boxes, but they would HAVE TO include a warning about these Al/Mg membranes. They bend if you look at them angrily. Or at least a warning that these are not suited for the households with small children. Remember, they are being produced with no grills.

Perhaps it's KEF trying to get us addicted to these cool little players so that we come back for more when we inevitably dent them. And dent them we will...