I’m still using a pair of KEF Transmission Lines that my late father and I built in the mid ’70s.
They are made of 1’’ ply and are a CJ Rogers design with a KEF B139 bass, KEF B110 mid, KEF T27 tweeter and an ITT-STC 4001G Super tweeter.
They sound really nice with any amp but could probably do with a crossover rebuild. And a refinish as the original glued laminate hasn’t aged well and has been removed.
I have tried to include a picture but it won’t stick for some reason.