Removing "ding" from speaker dome...

nickds1 · 19th July 2009, 02:37 PM

I have a pair of KEF XQ 5s, and very nice they are too (a semi-permanent loan from a friend in the industry... currently driving it with a Perreaux 2150B/SM2 combo for a bit of fun...)

However, on one unit, there is a small "ding" in the metal dome in the centre of the top driver - it came like that, and as its a loan unit, I can't just ask for another! I'd like to fix it as a favour (I'm an engineer...)

Is there a way to reliably "pull" this ding? Does its presence make any acoustic difference?

Thanks

chris661 · 19th July 2009, 05:30 PM

Yeah, there's lots of ways.

My personal favourite: the hoover.

Put it to the speaker dome, switch on, switch off (after 1 or 2 sec), remove nozzle.

If you pull it off before switching it off, you can cause mechanical damage.

Other options are things like needles which can poke it back around, but I find this tricky.

Acoustically, the dink will affect the dispersion and operating frequency of the dome (more of the former than latter).

Chris

Ron E · 19th July 2009, 10:10 PM

is this a tweeter or is it a woofer dustcap?

If a tweeter, don't use a vacuum, and I'd be hard pressed to tell anyone to use a vacuum even on a woofer dustcap. Sticky tape may work , but on a tweeter the metal is very thin and you may just make it worse. On a dustcap, a small pin can be used to tease it out. one thing that might work on a tweeter is to shoot it with canned air, holding the can upside down so that liquid comes out and makes it suddenly cold. I've never tried this, but it is the basis behind a lot of paintless dent repair in automobiles.

I had a tweeter where the metal dome was dented and it was measurable. I took the tweeter apart (D25AG35) and pushed the dent out form the inside. It no longer matches the other one, but looks/measures better than before. Any difference in sound was subtle.

Just looked up that unit, the metal bit in the center is a tweeter, and on top is a super tweeter. Whatever you try, you may just make it worse. That's an expensive set of speakers, and you might be better off replacing the dented unit, or writing KEF to find out what they recommend.

Andersonix · 19th July 2009, 10:43 PM

I've tried fixing dented metal dome tweeters, but it always left behind creases, even if I could actually dismantle it to reach the back side. In this case, I'd like to see pictures of the actual damage before suggesting whether to proceed with a fix.

planet10 · 19th July 2009, 11:31 PM

Quote:

Originally posted by Ron E
I took the tweeter apart (D25AG35) and pushed the dent out form the inside.

That is the approach that i'd take... i doubt the tweeter will ever be the same again thou -- by how much depends on how big the dent it.(once the metal foil is stressed it won't have the same strength again).

dave

Inductor · 20th July 2009, 03:51 AM

Quote:

Originally posted by planet10
That is the approach that i'd take... i doubt the tweeter will ever be the same again thou -- by how much depends on how big the dent it.(once the metal foil is stressed it won't have the same strength again).

unless (it) was made of Nitinol (memory metal)

nickds1 · 20th July 2009, 06:45 AM

The vacuum technique had already occurred to me, but I ruled it out as being too crude and possibly dangerous. I do have a small vacuum pen used to pick up SMDs and was considering that - a vacuum cleaner would be horrendous...

The guy who leant me the speakers is the one that dinged them - he's very much a pro with excellent subtle hearing, and he can't detect any difference between the two units.

I suspect that there are wider issues with the system anyway - the SM2 has a small"issue" on one channel, but the speakers sound terrific with the rebuilt 2150B.

Mooly · 20th July 2009, 06:47 AM

Bit of sticky tape and gently pull ?

chris661 · 20th July 2009, 08:49 AM

Sticky tape requires pushing at the dustcap/tweeter in the first place, causing even more damage.

Sorry, I was under the impression that it was a woofer that needed sorting out. Tweeters are altogether far more delicate.

Chris

flaevor · 20th July 2009, 09:18 AM

*Disclaimer I have never tried this with a metal dome.*

But you can take a tube, like the cardboard one from the paper towel or toilet paper roll. Place it over the tweeter and suck. This way you can control the amount of suction and duration. This works great for fabric domes i have never tried it on a metal dome.

19th July 2009, 02:37 PM	#1
nickds1 diyAudio Member Join Date: Aug 2005	Removing "ding" from speaker dome... I have a pair of KEF XQ 5s, and very nice they are too (a semi-permanent loan from a friend in the industry... currently driving it with a Perreaux 2150B/SM2 combo for a bit of fun...) However, on one unit, there is a small "ding" in the metal dome in the centre of the top driver - it came like that, and as its a loan unit, I can't just ask for another! I'd like to fix it as a favour (I'm an engineer...) Is there a way to reliably "pull" this ding? Does its presence make any acoustic difference? Thanks __________________ Nicko "The whole plan hinged upon the natural curiosity of potatoes" - S. Lem

19th July 2009, 05:30 PM	#2
chris661 diyAudio Member Join Date: Feb 2008 Location: Lancashire Blog Entries: 7	Yeah, there's lots of ways. My personal favourite: the hoover. Put it to the speaker dome, switch on, switch off (after 1 or 2 sec), remove nozzle. If you pull it off before switching it off, you can cause mechanical damage. Other options are things like needles which can poke it back around, but I find this tricky. Acoustically, the dink will affect the dispersion and operating frequency of the dome (more of the former than latter). Chris __________________ "Throwing parts at a failure is like throwing sponges at a rainstorm." - Enzo My setup: http://www.diyaudio.com/forums/multi...tang-band.html

19th July 2009, 10:10 PM	#3
Ron E diyAudio Member Join Date: Jun 2002 Location: USA, MN	is this a tweeter or is it a woofer dustcap? If a tweeter, don't use a vacuum, and I'd be hard pressed to tell anyone to use a vacuum even on a woofer dustcap. Sticky tape may work , but on a tweeter the metal is very thin and you may just make it worse. On a dustcap, a small pin can be used to tease it out. one thing that might work on a tweeter is to shoot it with canned air, holding the can upside down so that liquid comes out and makes it suddenly cold. I've never tried this, but it is the basis behind a lot of paintless dent repair in automobiles. I had a tweeter where the metal dome was dented and it was measurable. I took the tweeter apart (D25AG35) and pushed the dent out form the inside. It no longer matches the other one, but looks/measures better than before. Any difference in sound was subtle. Just looked up that unit, the metal bit in the center is a tweeter, and on top is a super tweeter. Whatever you try, you may just make it worse. That's an expensive set of speakers, and you might be better off replacing the dented unit, or writing KEF to find out what they recommend. __________________ Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan Science is a way of thinking much more than it is a body of knowledge. --Carl Sagan

20th July 2009, 06:45 AM	#7
nickds1 diyAudio Member Join Date: Aug 2005	The vacuum technique had already occurred to me, but I ruled it out as being too crude and possibly dangerous. I do have a small vacuum pen used to pick up SMDs and was considering that - a vacuum cleaner would be horrendous... The guy who leant me the speakers is the one that dinged them - he's very much a pro with excellent subtle hearing, and he can't detect any difference between the two units. I suspect that there are wider issues with the system anyway - the SM2 has a small"issue" on one channel, but the speakers sound terrific with the rebuilt 2150B. __________________ Nicko "The whole plan hinged upon the natural curiosity of potatoes" - S. Lem

20th July 2009, 08:49 AM	#9
chris661 diyAudio Member Join Date: Feb 2008 Location: Lancashire Blog Entries: 7	Sticky tape requires pushing at the dustcap/tweeter in the first place, causing even more damage. Sorry, I was under the impression that it was a woofer that needed sorting out. Tweeters are altogether far more delicate. Chris __________________ "Throwing parts at a failure is like throwing sponges at a rainstorm." - Enzo My setup: http://www.diyaudio.com/forums/multi...tang-band.html


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

19th July 2009, 10:43 PM	#4
Andersonix diyAudio Member Join Date: Jan 2004 Location: Silicon Valley	I've tried fixing dented metal dome tweeters, but it always left behind creases, even if I could actually dismantle it to reach the back side. In this case, I'd like to see pictures of the actual damage before suggesting whether to proceed with a fix.

20th July 2009, 06:47 AM	#8
Mooly diyAudio Member Join Date: Sep 2007	Bit of sticky tape and gently pull ?

20th July 2009, 09:18 AM	#10
flaevor diyAudio Member Join Date: Jan 2005 Location: Germany	Disclaimer I have never tried this with a metal dome. But you can take a tube, like the cardboard one from the paper towel or toilet paper roll. Place it over the tweeter and suck. This way you can control the amount of suction and duration. This works great for fabric domes i have never tried it on a metal dome.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
What makes an amplifier "bright", "warm", or "neutral"?	JohnS	Solid State	51	13th December 2009 06:42 PM
3" dome speaker	knarfje	Multi-Way	1	24th June 2008 02:15 PM
DIY "speaker box" ("BOOM BOX"). Help needed.	MASantos	Full Range	6	2nd September 2007 12:00 PM
6.5" silver flute with 1 1/8" dayton silk dome tweeter	jadenlinkletter	Multi-Way	10	28th February 2006 07:20 AM
Je labs 300b round 1 : Ding! Ding!	TubeHound	Tubes / Valves	9	13th October 2002 08:28 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read