Steve,
Man...I have to say, I doubted this DD-1 awhile back over on an 'insider' forum thread.
Well, I'm eating crow now. I first looked at this meter as-if it was the equivalent of setting gains at the amp's output w/ a simple 60hz 0dB tone. I originally said that the output of the amp would change based on the active load, and thus change the 'clipping point' vs a given volume level during music listening. And yes, it will...as I have shown in some of my youtube vids.
Well...I miss-judged the piece of equipment. At the time that I first heard/read about it, I was so caught up in disproving the forum-non-sense of setting gains based on a single 0db tone (be it 60hz or 6khz) that I totally overlooked the premise of your DISTORTION DETECTOR. I unfairly ruled it as a basic clipping detector based on singular tones/wave-function samples. But, after seeing its true nature in action vs other equipment, my mindset has changed.
I see now that your system/product is not based on testing a single or even multiple freq for simple 'clipping'. But rather it compares the total system signal to a base-line 'perfect' signal by which it is apparently calibrated. (please, correct me if I'm wrong...again)
Apparently, I jumped to the wrong conclusions far to early in my hasty 'nay-saying' of this piece of equipment.
I am still stuck on using my O-scope for testing, call me an OG...lol, but I'm contemplating on purchasing your DD-1 to help speed up my test and tune sessions here at the shop.
I'm looking forward to further developments in the evolution of this product.
-Canaan