Manuals help. Read them. Nothing in your receiver is actually a multichannel source so you'll be needing to understand the external sources that originate that kind of programming. Manuals.
Here's one...
http://www.retrevo.com/support/Kenwood-VR-309-Receivers-manual/id/480dj195/t/2/
Try the other manufacturers' support sites for your unidentified gear, by using a common search engine or these guys...
retrevo.com
audio.manualsonline.com
hifiengine.com
usermanualguide.com
vinylengine.com
Search Engine of your choice: "(product) manual"
'Large' is not literal in the context of Bass Management. It refers to the ability of a given speaker to handle REAL bass. Yes = Large, No = Small. 'Small' redirects bass from that speaker channel to the sub.
Web search concepts like bass management, speaker placement, multichannel sound, digital audio, etc.