Harbeth blog

@willemj

No, the others don’t just use generic polypropylene.

Sorry, that is what I thought. Anyway, the Harbeth material is a proprietary compound to have just the right mix of properties. See here for some of their explanation: http://www.harbeth.co.uk/usergroup/forum/the-science-of-audio/213-harbeth-radial-v-other-cone-materi...

Here is a close up of Radial mid cone

http://www.harbeth.co.uk/usergroup/forum/the-science-of-audio/1119-fast-and-slow-speakers-should-fas...

Here is is a close up of ATC mid dome

http://www.stereomojo.com/ATC%20SCM50ASLT%20SPEAKER%20REVIEW/images/ATC-Soft-Mid.jpg

Harbeth is injection molded (entirely plastic). ATC apply the “dope material” to a woven fabric. Both have a similar look and feel. Both are hydrocarbon based plastics. Both are softer than polypropylene and cannot be used for large cones (not stiff enough). Specifically designed material just for the mid range. What ATC use is even softer (tacky to touch) but the fabric and dome shape provides the necessary rigidity.

I am not aware of any others using this type of material but after so many years of use I can only assume the cat is long out of the bag and others do use it.

My Vienna Acoustics uses xp3 , Ithink that is the term they use for their plastic derived driver cones. They use some form of that through out their line.