IMF Loudspeakers

[peterm]

It's not the foams that i'm after it's the rubber ring that surrounds the foams.
I've actually done that bit

After looking for pics of the ALS30s online I see what you mean.

How about looking for self adhesive neoprene foam strip or sheet online and either sticking a length of strip into a circle or cutting an annular ring from a sheet?
The strip is often sold as draught proofing for doors or as greenhouse glazing strip.
The sheet has been suggested here in the past for making DIY gaskets for Naim SBLs.

Getting the right size may be tricky but there a lots of suppliers online you could look at.

 

[retrospective]

I don't know if that ring is functional or just cosmetic? You may wish to contact Jerry Bloomfield (Falcon) about that as he's very knowledgeable about IMFs. Even better perhaps would be Johan Nanninga, who I understand has reformed several of these mid-drivers (PM me for Johan's email).

I have noticed that quite a few refoamed als are minus the rubber surround having listened to them for 15+ hrs today i believe it is cosmetic

 

[retrospective]

Still here...

For those that were interested

The re-foam was quite easy and all seems to be working very well.

I removed the foam rubber surround..which i've concluded was merely cosmetic.(I believe it just hides any glueing mishaps/misalignment of the original foams)
That left the original foam which i cut off around the paper driver with a knife,gently peeled the remaining foam from the paper cone this was quite easy i did it by hand the foam from the outer came away quite easily as well.
A bit of a clean up with a knife and glued the new foams in place.
There was no need to remove the drivers from the cabs,i did find it easier to lay the cabs flat on their backs.
I'd advise the use of a 20-30 minute glue to allow a little fine alignment if necessary.
The doping on the mid driver (paper cone) conveniently terminates a few mm from the edge which makes aligning the new foams a doddle.
Any glue mishaps can be covered with foam rubber insulation as in the original design if req'd.

Good luck