In the last few days, thanks to the discussion about using speaker comp when going thru a solid state power amp and cab, I've read a bit about how a speaker compresses and tried to understand what the new algo simulates exactly, taking into account the way Cliff described it.
Basically, if I got it right, since a tube amp has a relatively high output impedance it's very sensible to the load attached so every variation in the load impedance translates in a loss or gain of output power.
Being a vaper, I know that when a metallic wire is heaten its resistance (in this case impedance) rises according to the TCR (Temperature Coefficient of Resistance) of the material.
This probably also happens in the coil of a speaker and when it is connected to a tube amp this rise of impedance causes a loss of output power resulting in a compression of the signal.
The question is: does this also happen with a solid state power amp? The answer from what I understand is no, cuz it has a much lower output impedance so it's much less sensible to the load impedance and the loss of power is probably negligible. The same reason for which a solid state PA frequency response is not affected by the impedance curve of the speaker.
So the conclusion is that, even when using a SS power amp and a traditional cab, using the speaker comp is desirable, hence no need to have two amps and separate chains when using Frfr and pa+cab simultaneously.
Maybe there could be other causes of speaker compression like the difference of air pressure that arises when the cone moves inside a sealed enclosure, or friction between the moving parts of the speaker.. But these (if they exist at all), although likely in different amounts, probably happen in every tipe of speaker cabinet including FRFR, so no real need to simulate them.
Does this make sense to you?
Disclaimer: what I wrote above is just the result of my reasoning so it could be totally bullshit, if someone has more knowledge on the matter please chime in to correct me.