The Music Tent, despite its name, is closer to an indoor than an outdoor venue. It's a permanent structure with a solid central roof section and walls, and only the "doughnut" from the roof to the walls is a soft material. Acoustically, it might make a better impression with a smaller ensemble, but obviously M8 presents a challenge just about anywhere. It's hard to imagine a successful performance here in Chicago at Orchestra Hall.
One cool aspect is that you can sit on the lawn for free. In my case, since this was part of a 3000-mile vacation, I was glad to buy a ticket. But it's nice to know that locals short of funds could enjoy good music without having to pay, especially since just about everything involving Aspen is so expensive. I'm not sure the sound outside the tent is amplified, but the tent "walls" are doors that swing open.
OT, I stayed at a ranch that is between Aspen and the Maroon Bells, and did the Crater Lake hike at the Bells. After that, I did a variety of hikes for three days in Rocky Mountain National Park. A memorable vacation, mixing high culture with some of the most beautiful country on earth.