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Today, I was working on my S75 speakers, and they had the frets off. My four year old son, who normally knows not to touch daddy's speakers, was helping me. The phone rang, and I went to answer it. I quickly realized that it was the wrong number, and went back to the room to continue with my project.
In the 10 seconds since I left this room, my son managed to dent both the midrange and dome phase link on one of my S75 speakers.
Any recommendation on how to repair the dented drivers? Of course, I just recently ordered a cap kit from Martin for this pair of speakers, so I would like to get everything working properly before I replace the caps on the crossover.
Thanks for your helping advance!
Pete
You have to be careful to not make it worse, be gentle so you don't misalign voice coils or such, but you can usually make it better or fix it.
One way is to take a very fine needle and poke it thru the driver material in the center of the dent, and gently pull out. Often you can pop it back out that way. Another approach is to use tape, wrap it around your finger so that the sticky side is out, stick it to the dent and pull gently. You want a tape that will stick enough to pull it out but not be so sticky that it damages the material when you pull it off afterwards. Be gentle and go slow and you should be able to save the drivers as long as they aren't to badly damaged.
Good luck with it.
Jeff
I'm afraid I'm recovering from the BeoVirus.
What Jeff said.Or a vacuum cleaner.Place the nozzle on the dent before switching on.
Martin
Oooh, good idea, I'd forgotten about the vacuum cleaner approach!
Some vacuum cleaners have a slider at end of the nozzle that opens up so the suction can be adjusted so it is not quite as strong. If you have a vacuum like that you might want to start with it all the way open first to avoid any damage.
John
Had exactly the same problem last week when my granddaughter found that she could take the fret off the BV6-22 that was standing on the floor in the office awaiting a new home. Within moments she had pushed the central dome of the two speakers inwards. These are fairly small but stiff domes.
Unfortunately the domes also now have creases in them, so they have resisted the vacuum cleaner approach (using a correct diameter tube selotaped to the suction and with a hole in the side to vary the suction with a finger), and the sticky tape solution did not work either.
So I am left with either the needle approach suggested by Jeff, or another idea on the web seems to be to epoxy matchsticks to the domes, gently pull out, and twist the matchsticks off. Sounds like a high risk of dome damage to me!
Another idea might be to carefully epoxy cotton thread to various points on the dome, pull out carefully, and then simply cut-off the cotton close to the dome face if it looks like pulling it parallel to the dome material will not release it without damage.
Last resorts: just leave it (does it affect the sound? ) or glue new domes on to replace the damaged ones. They are just dust caps, aren't they???
Graham
The good thing is that this doesn't seem to affect the sound as much as you'd think. Depends on how the driver designer did his job, if the dust cap is used to push the drivers freq response higher it will be more of an issue. More of an issue for tweeters than most woofers I think. If you can get them pulled out, a few creases won't be that important as long as the general shape is right.
One type of driver where this is critical is extended range or "full range" single driver systems, in them the shape of the center dust cap area is used as the high freq radiator and damage to it will significantly affect sound, but I don't think B&O, who pay a lot of attention to power response in the room and such, push their drivers out of the freq range you might expect to use them on in best practice. Extended range and full range drivers are a niche oddity appealing to a certain hifi set.
I know this could be a completely different thread about children and their creative interactions with B & O equipment. But, my daughter when she was 3 decided it would be interesting to play a CD on my Beogram 8000 turntable. The outcome was the needle at the end of the stylus was snapped off. This I discovered when I tried to play a record and the sound quality was non-existent.
vikinger:Unfortunately the domes also now have creases in them, so they have resisted the vacuum cleaner approach (using a correct diameter tube selotaped to the suction and with a hole in the side to vary the suction with a finger)
I modified a vacuum cleaner nozzle for this purpose by threading a length of silicone hose through the nozzle and filling around it with expanding foam.
The silicone hose is the type commonly sold for use as as vacuum lines in car engines and is a similar diameter to the air hoses used in aquariums but much softer so tends to seal better against the speaker dust cap.
This allows you to pull the dust cap at specific points and tease it back out again rather than trying to pop the whole thing back out in one go.
Hope this helps.
Martin.
My solution.
This is how one of the 6-22 speaker domes looked after vacuuming. Still two sharply dented areas. These are relatively small speakers, with a fairly stiff dome tightly radiused and more like a tweeter in a large speaker cabinet. (Not stiff enough to resist a child's attention!)
Note that the vacuuming was not focussed on the surrounding area!
Next, cut matchsticks are epoxied (Araldite Rapid) to the centre of the indentations, and held in place by tape placed across the speaker.
30 minutes later, epoxy seems sufficiently set. Tape is removed.
Whilst holding the dome carefully with finger and thumb (to prevent the whole spealer cone from being pulled forward) the matchsticks are carefully pulled forward. In one case the matchstick came away with the epoxy, in the other case I had to use tweezers on the epoxy residue. The epoxy forms a good bond with the rubberised dome surface, but will peel away afterwards with some manipulation.
End result is not perfect, but a lot better than the initial situation.
If your speaker domes have the same rubberised surface as the 6-22 speakers then epoxy could be the way to go.
Thanks to everyone who replied. I used the bent sewing needle method to pop out the dust cap on the 4 inch paper cone midrange driver. This worked well, and only took a minute. I still haven't tried to pop out the phase link, which is a 2 inch dome driver. I'm afraid to poke a hole in the dome. Also, it's tough to use a vacuum on this, as there is a plastic guard protecting this driver. I'll have to try the silicone tubing and vacuum method here, once I get a minute. I appreciate everyone's help!
A simple solution is to cut it loose (the whole dust cap), re-shape it and glue it back.
//Bo.A long list...
BO: A simple solution is to cut it loose (the whole dust cap), re-shape it and glue it back.
Some dust caps look as if they could easily be detached by lifting carefully with a sharp knife or scalpel. The 6-22 speaker dust caps looked too well bonded and too small to try this approach.