Do active speakers have high THD amplifiers?

Right nekoaudio, the distortion of the speaker far exceeds that of any reasonably designed amplifier.

pldhvymec, absolutely, a subwoofer mandates that the amp be hooked up directly to the driver. However, in my experience high power AB amps with extremely low output impedances do a better job of driving subwoofers. But you have to use passive subwoofers as an AB amp driven hard will get hot, they are larger more complicated and require
a larger power supply. Class D amps have become universal in powered subs because they run cool and can pack a lot of power in a small space.
I have tried several plate amps and Crown class D's with rather discouraging results. There are many Class D amps I have not tried so I can not generalize. The QSC PLX 3602 amplifiers I currently use do a wonderful job and they are relatively inexpensive being commercial sound reinforcement amps. Their bass is every bit as good as my old Krell KMA 100s and current JC 1's. They also have individual level controls for each channel which is great to have in a subwoofer amp for matching levels. Their only significant problem is a rather noisy fan but mine are below the floor in the shop so it does not matter. 

No, THD is THD, all amplifiers today have lower THD than the speakers they drive. The biggest improvement comes in the form of intermodulation distortion (IMD) which is virtually non-existent with active speakers. Intermodulation distortion is what your ears dislike the most, some people may call it sterile or mechanical, I call it accurate. I prefer to do it with my own amplifier choices using a DSP or electronic crossover. This gives you so many more choices than an active speaker where the speaker manufacture get to decide what amps, crossover points and slopes to use.  The biggest improvement will come in the way of much more defined midrange and high frequencies. I've been bi-amping and tri-amping for 42 years. Will only go back to passives when I need to downsize to move into a retirement community.

yes, very high thd... and imd... or else they wouldn't sound good...

just kidding

use your common sense... 

 Their only significant problem is a rather noisy fan..

<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>

Behringer NU12000 are the same way.. I have a few (:-)). I can find them for around 375-500. New or refurbished. They have 3 fans. I disconnect 2 of the 3 and put the third over the PS on a mini toggle.

Late night listening I flip the switch off. I have forgot several times and finally left it off. That was 2.5 years ago.. That is a bullet proof class d at 27 lbs.

Regards