Transmission line speakers!

@roxy54 not to nitpick but the oval KEF bass driver is the B-139. I worked at a KEF dealer and we had a speaker business as well w subcontract EE help and our own FFT and importantly ears to custom design transmission line  ( and other alignments ). The B-139 was a favorite for that duty as every TL requires “ trimming “ and KEF drivers had “ pretty tight “ tolerances for the day. We did a few B-200 in a TL and the Infinity Watkins 10” worked well in a “ poor mans HQD ala Levinson / Quad ESL system. We also carried Infinity ;-) no comment but sometimes advertisements get out in front of reality..but i confess to NOT dissembling every model, we had them all except IRS. Another dealer i worked at carried Freid / IMF and for tge $ or £ those were some impressive boxes…. fun thread…

Now, there are some advantages to a tapered TL alignment for the B-110 driver…ala KEF Cantata as i recall but…2 lazy to go look at the  B-110 file… a great mid for sure

@asvjerry i have the same one note problem, play a B e a n Flat…or so the War Dept. says…

On further review of the infinity marketing material that led me to think the monitor ilia is transmission line - it actually says that they “pack the other Enclosure with uniquely configured material that further damps the woofer and creates a transmission line load”.

I think the real magic is in the woofer itself which has damping material applied to the cone which stiffens it.  
 

they still produce glorious deep, deep bass, however it’s done.

tomic601,

Thanks for the correction, my mistake. Yes, it was the B-139.

My Vandersteen 1C’s are transmission line. The ‘port’ is a wide thin opening at the rear bottom. Now used in my bedroom system. Was laying in bed streaming last night before going to sleep, and never ceases to amaze the *quality* of bass those speakers are capable of. Are they as good as my 2CE Sigs or Treo’s in quantity of bass? No, but pretty good for what they are.