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Subwoofer started rattling


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Hi all - just wondering if anyone can offer some advice for an 18 month KEF KUBE 10 subwoofer that's started to rattle loudly, mostly from thundering sound effects in movies.

 

It's like the front mesh cover is vibrating. I've read it could be a tear in the cone, but not sure if this would mean I could hear it all the time, under any type of sound/volume?

 

I can't figure out how to open it up (if possible) to see if I can see any damage. Is this something that should be possible?

 

Thanks.

Edited by RocketShip
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Mine does similar, although usually from the back panel, so I get out my allen key and tighten up the back panel.

Hopefully a similar fix for you.

 

Edited by illusion
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2 minutes ago, illusion said:

Mine does similar, I get out my allen key and tighten up the back panel.

 

Thanks. Good to know it might be normal. Which model subwoofer do you have? Mine just has screws around the back panel and a bunch underneath. 

KEF-Kube-12b-Subwoofer-Rear-Panel.jpg

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This is the rattle noise, assuming it's not normal as I only started hearing it recently. Unless I've got it turned up too much or something configured incorrectly? 

 

 

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It's hard to tell for certain from a video recording, but it sounds to me like over-excursion of the woofer - possibly to the extent that the voice coil former is hitting the back plate.

 

It could be that you're asking too much from a compact 10" subwoofer.

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3 minutes ago, pete_mac said:

It's hard to tell for certain from a video recording, but it sounds to me like over-excursion of the woofer - possibly to the extent that the voice coil former is hitting the back plate.

 

It could be that you're asking too much from a compact 10" subwoofer.

Thanks - yes it does only occur when there's a lot of bass so maybe what's happening. It's just odd that I haven't heard it in the last 18 months I've had it. Shouldn't it have some sort of protection against physically bottoming out? Might be best to send the video to the dealer and KEF to see if  something has gone wrong as it's still in warranty.. Thanks again.

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1 minute ago, RocketShip said:

 Shouldn't it have some sort of protection against physically bottoming out?

 

Some drivers are designed to minimise the chance of this occurring  (with a 'bumped' back/bottom plate) but the reality is that any over-driven woofer can bottom out if over-excursion occurs.

 

Unfortunately active subwoofers don't have fail-safes in place regarding over-excursion due to incorrect settings/adjustments - and believe me, it's very easy to overdrive smaller subwoofers in an effort to get more out of them. I've got a HSU 10" sub which is a fantastic sounding sub, but it's very easy to over-drive it in my 6m x 3.6m room when trying to keep up with the main speakers at louder levels.

 

 

driver_excursion_1-1.png.db41e3036a9ebbe704aab7d0a7adb3e2.png

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2 minutes ago, pete_mac said:

 

Some drivers are designed to minimise the chance of this occurring  (with a 'bumped' back/bottom plate) but the reality is that any over-driven woofer can bottom out if over-excursion occurs.

 

Unfortunately active subwoofers don't have fail-safes in place regarding over-excursion due to incorrect settings/adjustments - and believe me, it's very easy to overdrive smaller subwoofers in an effort to get more out of them. I've got a HSU 10" sub which is a fantastic sounding sub, but it's very easy to over-drive it in my 6m x 3.6m room when trying to keep up with the main speakers at louder levels.

 

Ok, good to know. Maybe that is just what I'm experiencing. Any chance this has caused permanent damage? Obviously something I need to monitor regardless. The only way around this problem is to buy a bigger sub then?

Edited by RocketShip
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19 minutes ago, RocketShip said:

The only way around this problem is to buy a bigger sub then?

 

Or turn down the volume on the sub you have.  :)

 

Andy

 

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47 minutes ago, RocketShip said:

Ok, good to know. Maybe that is just what I'm experiencing. Any chance this has caused permanent damage? Obviously something I need to monitor regardless. The only way around this problem is to buy a bigger sub then?

 

It shouldn't cause damage if prolonged over-excursion hasn't occurred.

 

There's also the chance that there could be some other driver-related issue (e.g. the woofer dust cap is loose, or the spider has become partly detached). This could account for the issue only occurring recently (although, it also assumes that there are no other variables e.g. different program material with more bass content, changes in volume levels or crossover setting etc).

 

A physical inspection of the woofer should generally reveal any problems re: the dust cap or spider.

 

re: a bigger sub... I can hear the 'SVS' chant in the distance...

 

 

 

Edited by pete_mac
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1 minute ago, pete_mac said:

 

It shouldn't cause damage if prolonged over-excursion hasn't occurred.

 

There's also the chance that there could be some other driver-related issue (e.g. the woofer dust cap is loose, or the spider has become partly detached). This could account for the issue only occurring recently (although, it also assumes that there are no other variables e.g. different program material with more bass content, changes in volume levels or crossover setting etc).

 

A physical inspection of the woofer should generally reveal any problems re: the dust cap or spider.

 

re: a bigger sub... I can hear the 'SVS' chant in the distance...

 

 

 

Yeah, I'd love to know how to open it up to check if anything was lose. I unscrewed the bottom but couldn't remove it easily and it looks to be completely sealed. Tip for next time is to buy a sub that I can access..

I'm already thinking SVS; would need to sell this Kube first though. I guess the classifieds here might be a good channel for that, hard to ship it though with its weight!

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For anyone with a similar issue, I spoke with Kef and they have suggested the volume on the rear of the unit is just too high. Which leads me to think you guys were right and I'm just expecting too much from a smaller sub.

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6m x 3.6m room is no place for any 10" sub.. 2x 12" minimum or 15's

 

sounds like the KEF needs to go . svs are not the only sub maker but depends on your budget. 2nd hand the 2000 range pop up for around $900.. the 1000 range owners always want too much haha

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These days most subwoofers are using very high powered Class D amplifier. Very cheap to make now .The Kube hax 300 watts RMS ( 600 watts peak ) . Along with movies that have 95% effects and 5 % story line the drivers are under real pressure to keep pace and can easily bottom out .

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4 minutes ago, mavi said:

These days most subwoofers are using very high powered Class D amplifier. Very cheap to make now .The Kube hax 300 watts RMS ( 600 watts peak ) . Along with movies that have 95% effects and 5 % story line the drivers are under real pressure to keep pace and can easily bottom out .

Yup, that sounds exactly right. Perhaps I should have done more research before investing over $1000 in it! I guess it is better to go for a bigger speaker with more power like the SVS 2000?

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  • 4 weeks later...

Reminds me when I had similar weird rattling in the sub, turned it upside down and my 2yr olds wooden blocks fell out the bass port. He must have had great fun posting them. 🤣

Took quite some time to get the last two out.

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  • 2 months later...
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On 20/06/2020 at 9:46 PM, navlrac said:

Reminds me when I had similar weird rattling in the sub, turned it upside down and my 2yr olds wooden blocks fell out the bass port. He must have had great fun posting them. 🤣

Took quite some time to get the last two out.

thats a classic ! :D those ports are just so inviting I guess hehe

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