Damping factor or watts?

DF is limited by the inductor in series with the woofer to about 100. DF of an amp should be few times higher. Very high DF=4000 (Icepower) doesn't make much difference - at least at low frequencies. Low output impedance at higher frequencies helps to cut interaction between tweeter and midrange (especially with biwired speaker).

Power itself is not important - sound is. In order to get twice louder you need ten times more power.

Don't buy an amp for the specifications - buy it for the sound!!!

Icepower is class D - has high power, high DF and is not astronomically expensive (to answer your question).

I stated previously what ideal DF should be and I feel I should explain it more. In ideal world high DF would be great - but in real life it is often achived by strong global negative feedbacks resulting in tons of TIM and unpleasant bright hi-fiish sound. Recently many companies design amps with shallow feedback or no feedback at all. Yes DF is low but they sound great.

About power: Quality of sound is inversly proportional to amp's power (revolutionary statement!). 100W amp sounds better than 200W amp - let me explain: For the same amount of money you can find better sounding 100W amp than 200W amp. There is a lot of estate needed to make 2x more power but you can barely hear the difference when power is doubled.

In addition to all this - different amplifiers (and technologies) sound so much different - don't go by the spects. Icepower has good spects but specific sound - I like it (and have it) you might hate it.

Audiokinesis

Thanks for the info on Atma-Sphere S-30 - I checked and it looks very very interesting.

Audikinesis

DF=1 is a little extreme. On the other hand Atma-Spere design does not have transformers and capacitors in the signal path !!!. I would stay away from amps with DF>500. Icepower, I use, is a different beast and has inherently high DF (speaker always connected to V+ and GND - only direction changes). In addition TIM is a result of the charge traped on the junction of output transistors when overdiven momentarily - does not happen in Icepower.

Some amps with high DF (suggesting deep feedback) don't sound harsh or bright but make you tired after a while. It is because our brain fills the gaps when amp is choked-up after transitions (TIM). I would stay away from very good spects - something has to give. TIM was uknown 40 years ago!

As I remember, long long time ago 16 Ohm or even 32 Ohm speakers were typical and damping was easier. Lower impedance came with solid state's (I suspect) desire for higher power. Also, underhung speakers (narrow coil in wide gap) are rare inspite of their lower distortions - is it cost?