Hey OP.
Ideally, amplifiers are pure voltage sources. That is, the voltage at the speaker terminals is 100% determined by the input from your sources. Usually there's a multiplier, around 20.
So, 1 V in ---> 20V out.
But as the impedance of the amplifier rises, and the impedance of the speaker drops, this drops:
1 V in --> 18 V out.
And it can be frequency dependent, because the speaker's impedance is frequency dependent.
Take a look at the very first plot from this review:
https://www.stereophile.com/content/conrad-johnson-premier-twelve-monoblock-amplifier-measurements
and you'll see how this happens with tubes, with notoriously high impedance outputs.
This is not the whole story though, as amplifier feedback matters, so it may be that the amps can keep up but only to a certain current limit.
That's why I was strongly encouraging you to listen. If your Class D amp is rated for 2 Ohms, go by your hearing, not spec or class. If it has an actual issue you'll hear it.
Ideally, amplifiers are pure voltage sources. That is, the voltage at the speaker terminals is 100% determined by the input from your sources. Usually there's a multiplier, around 20.
So, 1 V in ---> 20V out.
But as the impedance of the amplifier rises, and the impedance of the speaker drops, this drops:
1 V in --> 18 V out.
And it can be frequency dependent, because the speaker's impedance is frequency dependent.
Take a look at the very first plot from this review:
https://www.stereophile.com/content/conrad-johnson-premier-twelve-monoblock-amplifier-measurements
and you'll see how this happens with tubes, with notoriously high impedance outputs.
This is not the whole story though, as amplifier feedback matters, so it may be that the amps can keep up but only to a certain current limit.
That's why I was strongly encouraging you to listen. If your Class D amp is rated for 2 Ohms, go by your hearing, not spec or class. If it has an actual issue you'll hear it.