High Efficiency speakers in general prefer an amplifier with a relatively high source impedance, due to the reactive nature of high efficiency drivers.
The use of low output impedance amplifiers with high efficiency drivers is the reason why horns have a reputation for being strident.
If you really are intent on this, add an 8-ohm resistor in series with the speaker load. True, you will dissipate likely up to 50% of your power in the resistor, but it will simulate (somewhat) a higher source impedance.
Or- you could get a tube amp. You won't need a lot of power. In the case of a high efficiency speaker, a good tube amp will clean the clock of any class D amplifier made.
The use of low output impedance amplifiers with high efficiency drivers is the reason why horns have a reputation for being strident.
If you really are intent on this, add an 8-ohm resistor in series with the speaker load. True, you will dissipate likely up to 50% of your power in the resistor, but it will simulate (somewhat) a higher source impedance.
Or- you could get a tube amp. You won't need a lot of power. In the case of a high efficiency speaker, a good tube amp will clean the clock of any class D amplifier made.