"Pooh Bear" wrote in message
...
2.83 volts is 1 watt into an 8 ohm load. For some strange reason most
speakers are 4 ohms but the manufacturers still use that same 2.83 volts
which translates to 2 watts, thus improving their speakers rated
sensitivity by 3 db.

I've heard of this cheat. I don't think that reputable manufacturers use
it.
Actually, most speakers are still 8 ohms IME.

IME the reverse is true. The majority of HiFi speakers are now 4-6 ohms, and
the majority of manufacturers quote sensitivity for 2.83V, if they state a
figure at all.

Since the impedance curve of most speakers is far from flat, specifying an
input voltage is just admitting the reality of what was usually done anyway,
even if it was mislabelled as 1 watt.

TonyP.