BBC research reports on bass traps

[igufi]

Came across these today, my apologies if these have already been discussed in ASR - a quick search did not show any hits.
- “A MODULAR WIDEBAND SOUND ABSORBER” - G. D. Plum
- “THE DESIGN OF A MODULAR SOUND ABSORBER FOR VERY LOW FREQUENCIES” - J.A. Fletcher, M.A.(Cantab.)