Kef ls50 meta cone cracking

Page 2 - Seeking answers? Join the What HiFi community: the world's leading independent guide to buying and owning hi-fi and home entertainment products.

plastic penguin

Well-known member
I can't believe listening to music at high levels, unless it's constantly played at distorted levels will cause such rips. These LS50s weren't made in huge numbers, so it's hard to swallow this pair got past quality control.

I would suggest the OP isn't giving the whole picture.
 
  • Like
Reactions: Al ears
It’d be nice to see a full photo of the drivers, but the first pic looks like external damage, the second pic looks like overdriving/fatigue. Fatigue doesn’t necessarily take place outside of the speaker’s and amplifier’s power limits - play bass heavy music, causing the drivers to move out further than theyre comfortable with, and you’ll end up with what looks like the right sided photo. A speaker like this should be used carefully in larger rooms or at higher volumes, and really, anyone wanting high output levels with heavy bass output should really be looking at another speaker. This is where a good dealer comes in, and shows the downside of buy-whatever-you-like mail order.
I will restate that if the speaker was used with an amp that is within the speakers stated specs it shouldn't end up with defects like this whatever type of music that was played through it.
You don't see manufacturers stating 'not for heavy metal' very often....
 

Tinman1952

Well-known member
May 19, 2021
1,365
798
2,070
I can't believe listening to music at high levels, unless it's constantly played at distorted levels will cause such rips. These LS50s weren't made in huge numbers, so it's hard to swallow this pair got past quality control.

I would suggest the OP isn't giving the whole picture.
Agreed. I suspect a UFO........unidentified flying object! 🙄
 
I will restate that if the speaker was used with an amp that is within the speakers stated specs it shouldn't end up with defects like this whatever type of music that was played through it.
You don't see manufacturers stating 'not for heavy metal' very often....
I don’t mean heavy metal, and I agree with your statement, but play heavy, exaggerated bass lines through systems and you can’t play them as loud as more neutral sounding music because the bass is too much. Continuous heavy bass played loud enough will result in what is show in the second photo - too much cone excursion.
 

Edbostan

Well-known member
Aug 5, 2021
163
77
170
I have a pair of Kef ls50 meta speakers bought in October 2021,noticed this morning that the meta cone has cracked in one place and showing signs of cracking in other areas. I will contact my supplier to get it sorted under warranty, but am interested in what might have caused the problem. The other speaker is perfect . My amp is a Vincent sv-237mk. I would be interested to hear if any other member has had a similar problem
The cracking seems to be near those ribs. Perhaps the ribs have weakened the integrity of the cone.
 

bigfish786

Moderator
Jan 29, 2013
553
351
19,270
Had a quick Google this morning and there are several other occasions of this happening to kef speakers. Hope the op can get these sorted,
makes you wonder if it’s too stiff to cope, or is there some obvious mismatch I am not aware of?
 

rayolight

Well-known member
Jul 21, 2021
77
34
70
Had a quick Google this morning and there are several other occasions of this happening to kef speakers. Hope the op can get these sorted,
makes you wonder if it’s too stiff to cope, or is there some obvious mismatch I am not aware of?
Really interested to hear this,have sent a message to kef no reply yet. NOBODY, goes in my music room,I do all cleaning, speakers see NO direct sunlight,my AE500's have similar metalic cones but no problems with them. I'm at a loss
 
  • Like
Reactions: Gray

rayolight

Well-known member
Jul 21, 2021
77
34
70
It’d be nice to see a full photo of the drivers, but the first pic looks like external damage, the second pic looks like overdriving/fatigue. Fatigue doesn’t necessarily take place outside of the speaker’s and amplifier’s power limits - play bass heavy music, causing the drivers to move out further than theyre comfortable with, and you’ll end up with what looks like the right sided photo. A speaker like this should be used carefully in larger rooms or at higher volumes, and really, anyone wanting high output levels with heavy bass output should really be looking at another speaker. This is where a good dealer comes in, and shows the downside of buy-whatever-you-like mail order.
The speakers have definitely not been overdriven, The strange thing is the sound from the speaker is not distorted,i only noticed the damage by accident
Pictures enclosed
 

Attachments

rayolight

Well-known member
Jul 21, 2021
77
34
70
The speakers have been looked after like all my equipment and definitely not thwacked as has been mentioned, the kefs are only 8 months old,I cannot stress enough that they have not been overdriven ,the room is only 10 x12ft,i have no children here, I'm 73 ,and average volume on my amp is 3. It was only a shadow on the speaker that made me look at it. I have noticed no problem with the sound which i find amazing, no fluttering which you would expect from a paper cone,think i could probably join break with superglue at a push if the supplier decides to be awkward. Interesting that there have been other comments regarding this problem on the web.
 

rayolight

Well-known member
Jul 21, 2021
77
34
70
I'm not very hopeful as I agree it does look as though the speaker has been damaged, which i can assure you it hasn't. Am sure the supplier will do everything he can to get out of replacement. According to kef the speakers are guaranteed for 5 years and I have only had them since last October, perhaps they should send a disclaimer if you play level 42 music. At a push I think I can join the tear with superglue. As I have mentioned before, there is actually no noticeable degradation in sound to my ears which I find amazing. It was only by chance I noticed the tear. Will have to wait and see 👀
 
I'm not very hopeful as I agree it does look as though the speaker has been damaged, which i can assure you it hasn't. Am sure the supplier will do everything he can to get out of replacement. According to kef the speakers are guaranteed for 5 years and I have only had them since last October, perhaps they should send a disclaimer if you play level 42 music. At a push I think I can join the tear with superglue. As I have mentioned before, there is actually no noticeable degradation in sound to my ears which I find amazing. It was only by chance I noticed the tear. Will have to wait and see 👀
If said dealer wants to keep your custom it is in his best interest to replace them.
 

rayolight

Well-known member
Jul 21, 2021
77
34
70
I've tried to send you a small video ,to show how little the sound is affected but apparently this is not possible
 

AEJim

Well-known member
Nov 17, 2008
80
19
18,545
I can't comment too specifically on the speaker (being from another manufacturer) but it's feasible for the cone to have been damaged that way in use - you have a powerful amp and vinyl in particular can put out some hefty low frequency information (not always audible) which can really push a smaller speaker driver even at modest volume. I experienced this happening first hand on very early AE1 mkIII's.

It's certainly the case you may not hear any obvious ill effect, there will be air leakage and the break-up/stiffness/dispersion will have altered but if the coil is undamaged it can be surprisingly subtle. If indeed the coil is undamaged it's another sign they may not have been overdriven for warranty.

The dealer should be your first port of call - they know you as a good customer and will be able to talk to their KEF rep. They may want to inspect the speakers and have them in for repair, at worst you may have to pay for a new driver if they determine it as "user error". Often it's at the dealer/manufacturer's discretion when the cause isn't obvious.

If you let me know your AE1 serial numbers I'll tell you the day they were made to clear up any confusion as to their age. ;)
 
The speakers have definitely not been overdriven, The strange thing is the sound from the speaker is not distorted,i only noticed the damage by accident
Pictures enclosed
Sorry, but from those photos, there’s no way that can happen to those drivers. They’ve either been stressed, or physically damaged. If they’re never stressed, aluminium cones will last many, many decades.
 

ASK THE COMMUNITY

TRENDING THREADS

Latest posts