During my visit to Lorantz Audio Services, the sole Australian loudspeaker driver manufacturer and similar in operation to GPA, I asked the owner if he had any light weight, rigid, 15 in. speaker cones. Well, he opened up and we could have had a good session on the topic. He had good things to say about the Altec 515.

Unfortunately I had an appointment elsewhere. He did say that he would like to recreate some cones from his days at the Rola organisation. Not possible. Current cone making fibres are not as stiff as the originals and the bonding agents currently used are water based and a give surface bond on the fibres rather than a penetrating bond that the original resins achieved.

The result is a heavier cone to achieve a comparable stiffness. Forest depletion and environmental regs. regarding emissions combine to thwart the time machine - at least in Oz.

Food for thought, Marshall.