Tekton Double Impacts

In fact I'd say if anything has been made clear regarding the Double Impacts over the course of this thread is their compatibility with a "wide" variety of amplifiers. 
C

Cranked up with very high power amplifiers?    

I think something at play here is the cabinet. It is only .75 inches thick even on the front baffle. It is NOT the most inert. At db levels of 110 dB they will undoubtably cause all kinds of vibration induced distortion and smearing. That is very, very loud and not something I would ever recommend for mere mortals. Anyway, put Star Sound Apprentice platforms under the DIs and you will hear a very different speaker at both low and very high listening levels. These speakers really need a footer of this quality to sound their best. I highly recommend Star Sound Apprentice platforms. I have no doubt they would have cleaned and sorted out the music much better. Food for thought.

Secondly, as I have said before the DI is a tad, just a tad, forward in the upper mids in stock form. I use Roon DSP and shave 1.75- 2 dB off the upper mids and find that perfect. I find this is needed more the louder the speaker is played. I understand the builder is now putting a resistor in series with the 6.5 inch mid drivers to accomplish the same thing. I find this interesting as I have been doing this since day one.

We don’t know the value of the resistor, but it is most likely 1.8-2.2 ohms. This would shave some 2 dB on an 8ohm speaker.

Agreed. I think one of the issues here is the very high playback levels with a very high power amplifier.

ATI is a well regarded amp. @nitrobob  Did you listen at 'mere mortal' levels and what were your findings under those conditions?

Bill ( @grannyring ) is correct in pointing out the value of isolating the DIs, and in fact, any speaker.

Agreed  Charles.  I've  listened with a few tube watts to a couple hundred SS watts.  The DI's have no "preference"  for what drives them.  There has been a huge variation in upstream equipment posted on this thread and most everyone has agreed the DI's reproduce clearly what is being fed to them.  For me amp choice is dictated by what I want to listen to.  There are some things tube SE designs will do what other amps don't.  And there is some music where I crave the firm control SS offers.  No different than pairing wine to your dinner entree.

I am at a loss to say exactly what accounted for nitrobobs experience.  It certainly does not bother or offend me.  But I have to say what he heard I have not. I have never heard issues with a nasal quality, driver integration, or power handling for what it's worth.  Any of these issues would have compelled me to ship these back as well.

I can only surmise, as was mentioned, you have to look at system synergy.  Furthermore, room acoustics can't be ignored.  Lastly, and I think this is a big one, is that we all have differences in our hearing.  If we all compared our audiograms, our ears would all measure differently.  Sometimes dramatically.  Is it any wonder we have different preferences? (and there are more complex reasons for our innate preferences beyond simple audiograms--but I'll pass on that discussion for now.)