Sound Reinforcement in Small Rooms
For a small room (up to 100 people or so) my preference is to run only vocals (and kick drum, if warranted by the genre) through the PA.
There are a lot of benefits to this approach:
- Audience members can hear more or less as they prefer. There's no escape from a multi-kilowatt PA. It's tough to establish a rapport with your audience when they're flinching from excessive SPL or going out to the street to have a conversation.
- Complexity is reduced tremendously. You're driving the room from the backline (plus vocals from the PA), so you don't have to do that (virtually impossible in a small room) delicate balancing act amonst stage volume, sweet spot on the guitar amps, and FOH volume.
- Setup time is significantly reduced when you don't have to set and level all those extra mics or worry about monitor mixes beyond what's needed for vocals. Most of the small clubs around here go with full-blown micing. The changeover time between acts is extended by fifteen to twenty minutes, minimum, just for the benefit of the sound guy.
- This should be really obvious, but I think it's worth restating: guitar amps sound best when they're pushed to a certain degree. In a large room (or outdoors) a good PA is essential to extending the limited coverage of an amp. But in a small room, micing a guitar amp through a PA does more harm than good.
- Assuming that the band is cognizant of dynamics and tonal balance (carving out a "space" in the frequency spectrum for each instrument), there's little that a sound guy can do to improve the situation in a small room. And if the band is clueless regarding those matters, the best sound guy in the world can do very little to improve the audience's experience.
- You don't really need the headache (when was the last time to got a monitor mix that wasn't useless in a small club?) of monitors for stage coverage. Arrange players and amps so that everyone can hear each other. In small clubs with lots of nearby reflective surfaces, this is rarely an issue. If you have a lot of people spread out over the stage, an extension cab is all you really need.
I've heard it done both ways, from both an on-stage and FOH perspective, and I much prefer the vocal-only PA approach in a small room.