I can’t resist but put in at least one of my $.02, maybe both.
Jam rock is not studio music. It’s live music. Its power and appeal are based on the interaction between themselves and the crowd, as well as between themselves and themselves.
In the studio the music is only engineered to a minimal degree and overdubs are sort of frowned upon. In general, the songs are basically platforms which serve as a foundation for, when played live, long sections of improvised rock solos. In a sense, jam music is kind of untrained jazz - same concept of interaction, but with rock rhythms and harmonies.
I have to disagree with your opinion in GD studio albums. Blues for Allah is one of my favs, brilliant IMHO.
Anthem of the Sun is also high up on my list, and this album does, at certain points, employ a more studio-music type of philosophy (i.e. overdubbs, sound effects only possible in the studio). Terrapin Station is also a very studio oriented album, arranging parts for strings and vocal choirs at various times.
Phish was my favorite band for years, but I have since moved on, rarely listening to them these days, if ever. Again, Phish’s appeal is in the spontanaety (sp?) of their live performances, which can’t be represented in the studio. There’s almost nothing spontaneous about making a recording in the studio.
I prefer to think of studio music and live music as 2 very different art forms. It’s a good way to think if you don’t want to be dissappointed by the studio work of a live band or vice versa.
BTW cooldude the bands you listed aren’t jam bands, or aren’t good examples of jam bands anyway. Check out Moe (no my username has nothing to do with them, nor the Simpsons, nor do they have anything to do with the Simpsons as far as I know), a great jam rock band with a hint of bluegrass, a pinch of Allman Bros., and a ton of energy. Medeski, Martin, and Wood are a great jam rock/jazz trio (jazz but with a strong jam rock appeal). The Zen Tricksters are very good. They were a GD cover band for years and years, and have, in the last few years, made their way into the scene with their originals - good stuff.