[Mat Nieuwenhoven]

On Sun, 21 Apr 2019 15:36:31 -0700 (PDT), wrote:

snip

If the SPL
is measured at 2.84 Volts, then the sensitivity will be less for the
16 Ohm version.

** The spec is for so many dBs *per applied watt* at 1 metre. For an 8ohm speaker this equates to 2.83V rms and for a 16 ohm model 4.0V rms.

Sometimes the makers will use 100mW for their tests as SPLs of 98dB and over are *very* loud.

Technically, you are correct. The 1998 book "Testing loudspeakers"
from D'Appolito gives the formula in chapter 2.8.3.
However, amplifiers don't amplify watts. They amplify voltages, and
have a limitation on the current they can supply: that determines
their wattage.
For practical use with given amp, a speaker with a higher SPL at
2.83V will sound louder than one with a lower SPL, even though the
latter one might be more efficient when looking at SPL/Watt.

Mat Nieuwenhoven