Play around with this calculator - read the notes
http://www.bobgolds.com/Mode/RoomModes.htm
be sure to explore this link at the bottom
http://www.bobgolds.com/Mode/RoomMod...References.htm
Here are some other thoughts:
http://www.acoustics.salford.ac.uk/a...om_sizing3.htm http://downloads.bbc.co.uk/rd/pubs/reports/1993-08.pdf http://www.rpginc.com/cgi-bin/bytese.../roomsizer.pdf
Bigger is usually better - make it big, then trim only as needed to get good ratios.
Like Wihtehouse sez, for a tracking room reflective surfaces counterpoised with boradband absorption as needed to adjust the reverb field strngth is generally most pleasing to the ear.
Once you have a preliminary plan you might want to post it here for some feedback:
http://forum.studiotips.com
Good Luck! thumbsup