I doubt you'll get many responses about the B's. They're not nearly as popular as the P's and S's in the Ety line. I realize they're marketed for "binaural" recordings; however, they work extemely well with regular, everyday recordings.
Before I purchased mine, I read a thread by, I believe "Vertigo 1" or something like that. That particular head-fi'er was very impressed with the B's. I also read somewhere (don't recall where) that stated that when Ety made the 4B's, they didn't make them to compensate for anything. As I understand it the others in their lineup compensate certain frequency ranges for how the music coming in interacts with the ear canal (or something like that) and that the other models also make "not so great" recordings sound at least listenable, whereas with the B's, you get exactly what is on the recording; nothing more and nothing less.
So what does all this blah, blah, blah mean?
In my experience, comparing my 4B's to a 4P w/P to S cable, I find the B's to offer even more of the crystal clear higher frequencies Ety is known for. I find that initially, the 4B's will sound almost lacking in the lower frequencies, but once my ears get used to the sound, everying clicks into place. I feel the 4B's are superior to the others in the line by a far shot. Take all the postive attributes used when others have described the sound of the 4S's and take it up a notch or two.
I listen to mine through a tubed headamp so if you've got a brighter sounding system, either source or amp, the higher frequencies might be a bit much. With the right combo, the Ety 4B's will provide sound that can truly be called "reference" quality.
I'll listen to the 4B's at home even though I've got several of the higher end circumaural headphones at my disposal. Are they good? Hell, yeah, they're good.
Ciao,