Today we had Rich Stillman and his four-piece group (banjo, mandolin, guitar, & upright bass) in to the Bose performance space. Rich wanted to tryout the system with his all-acoustic bluegrass band.
We first set up the way these types of bands traditionally do in live situations; one mic (AKG 414) picking up the entire group. The mix is acheived by the band members moving in to, or away from the mic. With one system set up behind them, it sounded very good in the room, but we couldn't get the volume up very high because of the inherent qualities of the large diaphragm 414 condenser (this mic is primarily used in the studio, and it picks up everything in its vicinity beautifully, but is very prone to feedback in live situations).
Next, we moved the system up to the front of the stage, about two feet in front of the musicians, and to the side. We got the volume up much louder and it sounded very good. The band could surprising hear themselves very well with the system in front of them.
Now for the good stuff....
We then placed another system on the other side of the stage, again about two feet in front of the band, and placed an MXL 993 condenser mic three feet to the side of the 414 (mainly to pick up the guitar). The sound just OPENED-UP! It was truly hi-fi, and we got it more than loud enough for probably hundreds of audience members.
If you play in a bluegrass band (or any other acoustic ensemble) this setup would be all you'd ever need for 95% of your gigs; and with only two mics, you could set it up in about five minutes. For the other five percent of your gigs, you could use the system as monitors (and to cover the first 25 rows) and give line outs to the FOH sound engineer.
Here's a picture of three of the band members (the fourth was out front listening) with one system at the front of the stage, playing into two mics.