Sound is annually provided by Sound on Stage - a fabulous group based in the bay area. Mains are uniformly L-Acoustics V-DOSC linearrays flown and subs along front of stage. The smallest of the stages this year used the 115XT HiQ's arrayed (I run a small array of the XT's as my rig ). SoS does a phenomenal job - the sound support is unending. Great people, all through the organization. I use them for larger gigs and was lucky to crewed Rooster Stage this year - hours of work and great fun.
Back to Allison Krause - I think one of her best is "New Favorite", which introduced Jerry Douglas joining her touring ensemble. Great mastering. I'd avoid the recent "Allison Krause + Union Station LIVE" CD - there is far too much crowd noise fake-o edited-in between and during tracks. Very distracting from the artistry.