93 db is a medium efficiency, not high. High would be over 100db. Plus you have to factor something else when you use the word 'senstivity'. It is NOT the same as efficiency.
The Senstivity spec is 2.83 volts measured at the speaker terminal and the sound pressure measured at one meter on axis.
Efficiency is the same, but measured with 1 watt at the speaker terminals.
If the speaker is 8 ohms, the two numbers are the same. If the speaker is 4 ohms though, now the actual efficiency is 3 db less! This is because 2.83 volts driving a 4 ohm load works out to 2 watts, not 1. All of a sudden 40-50 watts may not be enough!
I don't think the cost of the speaker plays a role here, although obviously if you are investing in a tube amplifier it only seems reasonable to use a speaker that allows the amplifier to perform in its best light...
The Senstivity spec is 2.83 volts measured at the speaker terminal and the sound pressure measured at one meter on axis.
Efficiency is the same, but measured with 1 watt at the speaker terminals.
If the speaker is 8 ohms, the two numbers are the same. If the speaker is 4 ohms though, now the actual efficiency is 3 db less! This is because 2.83 volts driving a 4 ohm load works out to 2 watts, not 1. All of a sudden 40-50 watts may not be enough!
I don't think the cost of the speaker plays a role here, although obviously if you are investing in a tube amplifier it only seems reasonable to use a speaker that allows the amplifier to perform in its best light...