If I can think of something then I'll mention it to the OP accordingly.
In the meantime based on my experience I was giving you an alternative view to some of your comments.
Since SCM40A's were launched in April 2015 I've used numerous all in ones with SCM40A'S and also over the years with other actives such as SCM19A's, Classic SCM20ASL's and SCM100ASL Pro's. There's no place to hide with the SCM100ASL Pro's. Anyway, the finest I've heard from ATC actives using an...
753's are still excellent speakers. They were launched at a RRP of £600. I bought a new pair in February 1993 and they had and still have a level of build, fit, finishing that even now some speakers up to £5k can't muster. The issue the OP is having is in the main down to the interaction with...