We have no idea what level Ralph's measurements were taken at, it's not specified. It's also curious that the LDSG unbaffled response looks most like Ralph's whereas the LDSG baffled measurements look a lot smoother. I don't have much confidence in the relationship between these measurements and reality.

Anyway if this 'resonance' vanishes at 80dB in the mid range then that's more than loud enough for me to not care about it....

The point remains that if you're going to tie your subjective impression to this then you have to try a lot harder to demonstrate it. We'll leave your criticisms of the lack of foo-foo dust in the ATC internals for another time...

Paul