S45-2 speakers sound better than they should - pure serendipity in my view. The S75 rather wrecks it by having a loose bass and slightly sharper top end but some of us like that at times! The later twin grille S45 is not similar at all - the S55 is the speaker to compare instead, and this too is a super small speaker.
Unfortunately, the only way to judge speakers is to listen and compare and few of us will get the opportunity to do that now. Make friends with Martin is probably the best way! 🙂
My B&O Icons: