Fixing a dented dome on a loudspeaker

[ppppenguin]

I've been given a pair of Alesis M1 Active Mk II speakers: https://www.alesis.com/products/view/m1active-mkii One has a dented dome on the woofer. Not the easiest thing to photograph but I've attached one anyway.

I can't imagine it will affect the sound but I'd like to straighten it out. I thought of using a VacuVin pump: https://vacuvin.com/ but it's obvious that there's no way to get a decent seal and hence no suck. I tried using my vacuum cleaner but got nowhere. It's a powerful machine but even at full speed it got precisely nowhere. Again there's not much of a seal round the nozzle. If I can find it, I've got an alternative large diameter hose (intended for clearing wet leaves, drains etc) which may completely encompass the dome.

I took great care, starting with the vac on low speed and gently holding the cone.

Any ideas?

PS: As an aside, the user manual suggests you can adjust the bass response (mainly to compensate for using them too close to a wall or corner) by partially or fully blocking 1 or both of the reflex ports. Stuff a sock in it!

[Doodlebug]

Make the tiniest of pinprick hole in centre of dent.
Insert a piece of bent wire (90 degree bend) by wiggling it about, them gently pull on wire
to pull out dent. Remove wire by wiggling it out.
Hole can be filled now but don't think that is required.
Dia of wire to start small then bigger if small just comes out of pinhole.

Risk is yours. :-)

[boater sam]

Superglue on the end of a blunt cocktail stick then soak it of with a drop of very dilute washing-up liquid.

[Mark Hennessy]

If you're really lucky, there will be a vent through the pole piece - that's quite common with higher-powered bass drivers. I only found one photo that sort-of shows the rear of the drive unit, but the lighting isn't good enough to see whether or not there's a vent in the middle of the bucking magnet.

Failing that, the pin method will be fine. Though in my experience you can usually manipulate them without having to suck or pull - just a case of gently pushing in the right places. Won't always be possible, but always worth a try. You probably already have, but most people I know give up far too soon

[ppppenguin]

I really can't see a way of pushing it back into shape. If I can find the wide vac pipe I'll try sucking as non-invasive. Otherwise I may just leave it.

These may end up as my main speakers for a while. On the face of it they are pretty good - they are certainly widely used professionally as nearfield monitors. Neither Ruth nor I like how they look for domestic use. I've got various fabrics including some speaker grille cloth so there's scope for trials.

Another annoyance is driving them. As expected my Quad 33 hasn't really got enough output, even with the gain controls on the speakers turned right up. I'll frig some resistive attenuators from the output of the 405 as a temporary measure. About 8:1 attenuation should be about right, the controls on the speakers will do the fine adjustment.

[peter scott]

Many years ago when I had speakers that we didn't like the look of I made bags to cover them. I had been storing them for at least 20 years but was persuaded to sell them last year and took some photos for the advert.

Peter

   

[Nick]

I've used a syringe as a small vacuum generator in the past - glued a rubber washer on the end, placed it over the dent then very gently pulled the plunger back. Did a pretty good job on some damaged very expensive Kefs.

[Murphyv310]

Thin plastic flexible tubing.
Rub the end with damp soap and put it over the centre of the dented part, suck the other end and lightly pull the tubing, can also be done using a decent sized syringe. Always works for me.