Emotiva XPA-1 or Wyred SX/ST-1000

Magfan, You are right about stopping speaker motion by shorting with a paper clip (high DF). Pushing the speaker cone out of its magnetic center creates potential energy, and with an open circuit, the speaker will oscillate a few cycles and stop by itself. Shorting with a paper clip stops the motion abruptly, as would a high DF amplifier. Details in Bass Guitar notes, for example, are obscured by extra cone motion if the DF is low because it keeps moving when the source signal has stopped. The heavy JBL woofers I described failed to produce the sharp crackle of a lightning strike until I kept increasing the DF of the amplifiers. My testing and listening with several amplifiers with varying DF's led me to my conclusions. For example, when I connected a $6000 Classe CA-2200 to woofer section, It took only a minute of listening to know it was the wrong amplifier and I disconnected it. When I connected it instead to the compression drivers crossed over above 650hz, the highs sparkled with crystalline delight! Classe didn't state a DF in their specs. Some research told me that their DF was slighly less than 100. Their amps use next to zero negative feedback, making for wonderful mids and highs. The tradoff is lack of woofer control. If you have speakers with separate terminals and jumpers, you can remove the jumpers and use separate high DF amps for the woofers and another amp such as the Classe for the mids and highs. Believe me, I have done it and in every case, there was a noticable improvement.

Thanks for reply, Fmk.

One additional factor to consider. Yep, hi mass cones are a potential problem, but I think that speaker 'Q' is part of the answer.
A system with hi 'Q' will have plenty of overhang and maybe even a midbass peak and bloat. A critically damped system of 'Q'=.7 will produce good bass, maybe even with a low DF amp.
NFB? maybe the '3rd rail' of hi fidelity.

wyred for sound has the typical nice ice sound but holloow I owned a st 500 for several months could not take it anymore bought a modwright 100st then went to the emotiva
xpa-1 mono blocks give em 250 hours runin and they are very good on Bass I have mig maggi 3.6 and to get good bass out of them you have to have control .I also have wilson sophia 2 and they sound excellent for $2k
it will beat most $6k amplifiers in the magazines.