#1
I just had a little thought... (Yay me!)
Is there some sort of formula to tell if your amp will be loud enough for a certain size room/crowd.
I know it will vary from outdoors to indoors but for now I just want to know indoors.
Im thinking of something related to the wattage.
ie: 1watt=how ever many feet it can be clearly heard
My gear so far:

-Cort KX5 (pearl white)
-Crybaby Wah
-Danelectro Cool Cat
-Fender Twin Reverb 65' Reissue
-Hardwire TL2
#2
It would depend on many factors. Firstly, like you said, amplifier power. Second, it would depend on the efficiency of the speakers you are used, combined with the amount of power compression of the speaker at the max output of your amplifier.

Another factor would be how far the crowd is from your speakers. You loose 6 decibels with every doubling of distance. However, indoors depending on the room, you will get boundry reinforcement. There isnt really a simple formula, unfortunately.

Approximately how many cubic feet is the venue? and what amplifier and cabinets are you using?

Washburn X50PRO FE (GuitarHeads active bridge pickup)
Dean Vendetta XM
Jet City JCA20H head, w Eminence Texas Heat 12"
Danelectro Transparent Overdrive
Ibanez TS7
DigiTech RP-255
Behringer VD1 (Big Muff PI clone)
#3
No, there's no formula as amp volume is determined a lot more things than wattage, and also the room you are in, it's size, the material used in the construction, where you're playing will influence sound distribution.
#4
Duh. Didnt take that into mind....
Not everyone has there amp at 10 all the time... =p
Ok well I guess ill just have a friend stand as far back as the crowd and ask him if it still sounds good. =p
My gear so far:

-Cort KX5 (pearl white)
-Crybaby Wah
-Danelectro Cool Cat
-Fender Twin Reverb 65' Reissue
-Hardwire TL2
#5
If you talking about your fender twin reverb, then dont worry that amp will handle any gig inside or outside.
#6
Quote by sstony
If you talking about your fender twin reverb, then dont worry that amp will handle any gig inside or outside.


+1

You have to also consider that most gigs you will mic up anyway...