Basic question about sensitivity

@erik_squires - not disagreeing, but at least Stereophile and Hi Fi News are trying to be as informative as possible. But what the EPDR measurements of a range of speakers do tell us is that, in general, speakers are harder to drive than most manufacturers' generally used specifications tell us. So my rule of thumb is to take the nominal impedance and assume that the real impedance is lower than that.

@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.

@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.

The EPDR measurement used by Hi Fi News and Stereophile gives a better indication of how difficult a load a speaker will present to the amplifiers.

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

@OP and Erik_Squires, I just took another look at the LS50 Meta's measurements - it has a couple of tough impedance/phase dips in the bass and low midrange and it's insensitive, so might not be the best choice for the amp in triode mode. However, the crossover design choices have yielded a really very fine set of measurements otherwise.

@OP what I meant by polarising is that some people love LS50s and other's for some reason don't like them at all. In fact, that may be due to the fact that they are a tough speaker to drive. I went back and had a look at John Atkinson's measurements for your V12. On paper, even accounting for the 4 Ohm tap, they don't look like an ideal match for one another - due to the tough load and limited efficiency. However, a lot depends on what kind of music you listen to and what volume you listen at.

@OP There is no problem using a 4 ohm speaker with your V12 as long as the speaker is fairly close to it's nominal impedance. But you probably want something in the region 87dB. But if you are sill happy with your 805s, I wouldn't be rushing out to change them.

AOP - you're welcome.