Basic question about sensitivity

The B&W 800 series are a good example of speakers that are relatively efficient but difficult to drive.

@yoyoyaya , I am running an ancient (going on 30 years old) pair of B&W 805s; I just took a look at the literature that came with them, and it states that the sensitivity is 87 and nominal impedance is 8 ohms. Since I have owned these speakers, I have ran them with three different tube amps, and am currently running them with one that is switchable between ultralinear and 50 wpc triode, and mostly always I have used the triode setting. I had never thought of these speakers as being particularly hard (for any of the amps I have owned) to drive; but with that typed, the largest room I have ever had them in was probably on the small side of medium, and presently, the room that they are in now is just plain SMALL.

@OP. I owned a pair of 805s for a number of years. Very nice loudspeakers and not difficult to drive. The newer 800 series - the floor stand speakers in particular - are a different kettle of fish entirely.

@yoyoyaya  , thanks, that's interesting (particularly since I am kicking around the idea of upgrading).

Given that my 805s are going on 30 yeras old, and taking in account for inflation and technology, how far do you think I'd need to go to make a significant upgrade?

@OP. Just speaking to your opening post. I think it would be well worth you while listening to a pair of P3 XDs. As you will gather from some of my posts on other threads, I'm not overly enamoured of the direction B&W have gone in voicing their recent speakers - and they are getting quite expensive. You might also want to listen to a pair of M30s or Spendor Classic 2/3s if you feel you need a bit more scale and bass extension. Lastly, though they are a bit polarising, I would listen to a pair of Kef LS 50 Metas, which are outstanding value for money. The foregoing comments are based on personal experience of all of those loudspeakers and of the current B&W range.

Try Tube Amp(s) now or some day?

That is why I recommend starting/auditioning higher sensitivity speakers, hopefully finding one you really want.

Also, avoid speakers whose impedance drops a lot from it's 'nominal' impedance rating, that will effect/limit the amps to ones that can properly handle low impedance.

Lower power needs lets you select amps/tube amp(s) that are smaller, less heat, more placement options, as well as being in a more competitive price category.

My friend is currently looking for a pair of 100 wpc tube mono blocks. Very limited, big, heavy, hot, big price