I recently went to a classical/fusion jazz quartet concert. The system sound was a pair of SR1530 Mackies (+ a Makie mixer). These are tri-amped 15'' speakers, and the sound is absolutely amazing, nearly studio quality: well balanced, punchy, and crystal clear. They are heavy for us, solo guys. I wish there was something close in quality but lightweight... http://www.mackie.com/products/sr1530/index.html

-- José.