I am not going to spend the time reading all the posts. My impression is this; it seems the sub doesn't get you much farther down than the mains. While it may seem marginal, a sub that can do about 15-16Hz is SUBstantially, different - sorry, had to pun! - than one which can do 25Hz. BIG difference.
I would not give up on subs without considering an alternative, as I'm sure others have suggested.
My experience; I have the Kingsound King III ESL and love them with subs. I use the Legacy EXTREME XD Subs with them and wouldn't dream of runnning the King III for realism in listening without subs. Sure, the King III reaches similar to the 20.7, but the extra foundation is precious on genres of music. Imo.
Disclaimer, prior to owning I reviewed both the King III and the Legacy EXTREME XD Subs for Dagogo.com
I would not give up on subs without considering an alternative, as I'm sure others have suggested.
My experience; I have the Kingsound King III ESL and love them with subs. I use the Legacy EXTREME XD Subs with them and wouldn't dream of runnning the King III for realism in listening without subs. Sure, the King III reaches similar to the 20.7, but the extra foundation is precious on genres of music. Imo.
Disclaimer, prior to owning I reviewed both the King III and the Legacy EXTREME XD Subs for Dagogo.com