wrote:
I have an 80 wpc amp and am thinking of replacing my speakers.

I had read that sensitivity is often compromised in higher end speakers
because higher end amps are often high wpc so can still drive them.
Although this sounds plausable I've also read that valve amps are ofter
low wpc. Besides dont amps prefer less work so they have more power in
reserve for fast transients?



A very interesting question!

As I recall from many years ago, low end performance and sensitivity
could to some extent be played off against each other: That is to say,
that for a particular cost, a 'speaker could either go deep in the bass,
or be sensitive, but not both. To achieve greater low frequency
performance with greater sensitivity requires a much stronger magnet,
hence more cost.

When size of box is also factored in, then a small box can go low but
not loud, and vice-versa.

What all this distils down to, as far, again, as I recall, is that cost,
size, bass performance, sensitivity and maximum loudness are all
interrelated.

If I were in your position of having 80 watts available, this is
sufficient for quite high levels with 'speakers of average sensitivity
(say 86dB/watt) so I would choose on the basis of sound, size and cost.
Choosing very sensitive 'speakers (say 100dB/watt)could bring the
noise levels up to be noticeable and make the volume control very touchy.

S.