I'm unable to even get a word out, gulp!
Roger never liked his Ric sound, he thought there was too much distortion, he wanted a smoother "more American sound", "the grass was always greener" for him "on the other side". During the remaster and remix of Machine Head he even described it as "messy with too much side noise".
And that is why he has what he has with his Vigiers today, a very clean and pure sound with no nasty frequencies (which we all tend to love but he doesn't!). Very much a "producer's bass sound".
He never realized that that Ric sound on Machine Head
and its even more distorted version on the Made in Japan album influenced a whole generation of bass players. I believe he used stacks of Martin bins in the 70ies to boost his sublows (but he probably never heard those sublows
on stage with the racket Jon Lord and Ritchie Blackmore were making). I certainly never found his Machine Head/Made in Japan-era sound anything but full and not too trebly at all.
Did they say anything about Ritchie at RRHOF?