Can speakers or cabinet size lessen sustain?

[MichiganboySB]

I apologize for wearing the carpet thin on this but I'm really trying to be certain to this being my gear's problem. As you might have read before I use two 1x12's for my Dual Rect and the notes just die out. I plugged into my bud's Dual and Marshall 4x12 cab and was in heaven. What is it about a 4x12 that supports your tone's sustain? I mean is it that the speakers can vibrate more within a larger cabinet or what?
I'm about to go out and get a 4x12, been thinking about avatars but I'm so anxious that I'll prolly go into GC and get a traditional cab. At this time whenever I pick up my axe and begin to wail it just annoys me, I need to jam! Its a release for me, all this frustration built up must be released! I know you know what I mean!
Cya,
Ken

 

[FPFL]

You are very likely barking up the wrong tree. Sustain problems that big are not cab related unless your speakers are damaged. Something is wrong with the amp or the guitar. I can get crazy sustain out of a 9V micro-marshall stack with the right guitar.

-P