Sorry to resurrect a dead thread but I registered just to comment on this. I didn't read all three pages so forgive me if this has been covered.
I'm in a Red Hot Chili Peppers tribute where the bass obviously has to be pronounced. I NEVER turn the Rumble 350 past half at practice or live.
If I can't hear myself at practice, one of two things need to happen. Either the guitar needs to turn down, or I need more SPL and hearing protection. Suffice to say the guitar turns down. Practicing quietly is good practice for keeping stage noise down at your gig. After all, you want your fans to hear what the sound guy sends out, NOT your amp.
Using the Rumble 350 live, I can barely hear it at half volume, but who cares? That's when you yell to the sound guy "More bass in my monitor."
For reference, here's my live setup.
Custom Carvin with dual radiused alnico V hum-buckers blended 50/50, 18v preamp with gain pot maxed, all eq's set at detent and volume maxed.
Line 6 G30 straight to Rumble 350 with no 6dB pad
Boss limiter/enhancer, bass chorus and digital reverb(rarely activated live) in that order on effects loop
No scoop or punch, eq flat and horn on.
Cheap switch for distortion with blend at 100% and gain at 75% (for "Around the World")
XLR out with ground lift activated going to PA.
The only issue I've had was the horn putting out bad static suddenly after a few months of use. I pulled it apart to find that most of the connections were plug and not solder. Not surprising as this combo is cheap and one of the ways they do that is by not paying someone at the factory to do that extra soldering. I cut the connectors off, stripped, tinned and soldered the horn connections, horn switch connections and board connections. Problem solved.