Speakers to replace Proac Response 3's


Im asking this on behalf of my father who's been out of the hobby for some time, he currently has Proac response 3's and is contemplating upgrading, his requirements for the new speakers would be,

- they can be absolutely no bigger than the proac's, and preferably smaller
- they have to be able to FILL a 20 x 20 x 12 foot room with sound
- budget of maximum $3000 new or used
- must be a significant upgrade from the proacs

my father listens mostly to jazz, but good performance on everything would be appreciated, he also has a sub so extreme low frequency is not essential.

associated equipment:

bryston 7bST monoblocks - 500w into 8 ohms...power is not a concern
Sonic Frontiers Line 2 Pre amp
Arcam Alpha 9 cd player
Oracle Delphi Mk 5 Turntable, with Graham 2.2 arm, and Grado Statement Cartridge
mbacinello
What about the Joseph Audio RM22si signature Mk2 speakers? Please see http://www.josephaudio.com/product.rm22simk2.html

Or, for a little more money (`$3,500), the Joseph Audio RM25 Mk2 speakers. cheers..
he certainly likes the Proac sound. just looking for something better, and if possible for WAF reasons less physically imposing