Guy, I was surprised to learn that the current EP500s don't have the Trim adjustment, since the information on the site still shows it and I found it to be quite useful in the locations that I tried for my EP500. I wouldn't have praised it to you in a previous reply if I'd known this.
The subsonic filter has nothing to do with what Trim did previously. I understand that the earlier EP500s such as mine had a fixed subsonic filter at about 18Hz. Now that filter can be selected or not on the latest versions. Making it optional isn't related in any apparent way to the boost which the Trim adjustment gave in the second octave of bass from about 40-80Hz.
You mentioned the manual parametric equalizer on your 772 as a possible solution, but in looking at the 772 manual I see(pp.62-63)that the 772 isn't one of the receivers where the equalization can be applied to the subwoofer channel. So, if your room does in fact make a mid-bass boost desirable this can't do it.
