I've had Salk SongTowers (dome tweeter) and now the Veracity ST. I also have DIY CAOW1 speakers, very similar to SongSurround Is.
Unlike other speakers I've had in the past, none of them require high volume to sound good. They sound neutral, balanced (neither laid back or aggressively detailed) and produce good off-axis images at low and high volumes. Most, if not all, Dennis Murphy-designed Salk speakers seem to share this ability.
I own Veracity STs (and love them), I've heard Song3-As and also like them. I've not heard the Silk Towers, but I'd be surprised if they didn't also work well at low volume. I think any of your 3 picks will do well for what you want.