The MAS cabs, in general, don't tend to distort much -- they also stay more dynamic than most cabs, up near the top of their range. Compression and other kinds of distortion, even if subtle, are "I'm getting loud" cues that might not be present as much.
There's that and the fact that you're not playing "in context" with other players/sound sources as reference -- regardless of cab, I find that that makes a difference in how we perceive volume. (Corollary: Be careful with your ears pushing a loud rig at home.)
Two more things:
- I don't know how big your cabin is [EDIT: 150 sq ft -- not too big], but if you've got too much cab for the space, you can "overpressurize" it (at least that's the term I've seen used) and things will start to sound and feel compressed without getting louder (if you back off and things clear up, that's one sign that this might be happening -- extreme plate-rattling could be another
). The MAS cabs seem more prone to this in small-for-the-cab spaces than most other cabs (though they are -- and I can vouch for this from experience -- less prone to exciting specific room resonances or getting "sucked out" in nulls). Of course, with a 1200 Watt amp (guessing your cab is 8 Ohms, though, so less than that?), you'll want to be careful of overpowering the cab (which could also result in things feeling compressed/not getting louder as you turn up), but I'll trust to your good judgment on that (and maybe you're not experiencing any of this, anyway).
- Due to the way the sound drops off less with distance (at least within a certain radius -- this is discussed way back in these threads) and to some of the other effects of how these cabs work, you need less volume on stage to carry a room. I also find myself less reliant on stage monitors (and prefer not to be in them for the most part) and find that the mix on stage is generally more clear.
But, yeah, regardless of rig, it is possible to be a good deal louder, playing solo, than you realize, particularly if your rig is staying pretty clean and dynamic on the way up.
Live, things, as you know, can be weird -- sometimes you need less rig/power/volume than you think, sometimes more. Having had an older model, less potent 46 than yours, though, I'll say that if I was pushing it at home alone, I'd definitely want hearing protection in.
Since you're in a cabin and you mentioned playing music through the cab, try this: Put some music on at different volumes and go for a walk outside, around your cabin and some ways away. Maybe try it with your desktop speakers, too, at what seems a comparable volume/EQ when you're in the room. Report back on what you hear, please, and enjoy!
