they are quite deep and high but moderately wide (see specs: 14.3 deep and 23 cm high and 8.8 cm wide). There is no subwoofer, it's an extra feature so that the bass comes in strong - and it does come in strong. I have my bass turned down to about 1/3 of the maximum. Classic Creative sound if you ask me.
Ventilation I can't really tell you (except that it's passive :) ), never ran it a full day either, but I couldn't see/feel any heat issues so far.
Hope that helps.
Greetings
