Jazz, folk and classical recordings are generally documents of a performance, and the engineers goal is to capture what is happening the studio as accurately as possible. Rock and pop on the other hand are about building sonic artifacts in the studio, and the source material plays second fiddle to the finished product. In electronic dance music, the source material has no real existence at all outside of the context of the finished work.
Because it's about documenting a performance, jazz is pretty much exclusively recorded live, with no overdubs. Partly this is because multitrack recording only really took off in the 60s, well into jazz's lifespan. More importantly though, as petergunn says, the whole point of jazz is that musicians are playing spontaniously with one another and the give and take of playing together is happening
in real time. Overdubbing abstracts that real-time relationship. Most purists would be hardline about it and say that records using overdubs aren't really jazz records, and I've got some sympathy with that view. When you boil away all the nebulous talk about vibe, cool, groove, feeling, etc, jazz is defined by that real-time, real-space relationship.
Working in real time doesn't preclude using the studio as an instrument, but jazz players want to play in close proximity to one another so they can communicate visually and through body language - and because their instruments are acoustic, you can't seperate the sound source from the player. This creates big problems for engineers in seperating the instruments, because they all tend to bleed into each other's mics. This limits the scope of the producer for controlling the individual sounds, and it means that in terms of timbre jazz records tend to sound very similar to one another.
Jazz has flirted with multitrack recording. Bill Evans recorded
Conversations With Myself, where he used overdubbing to play two piano parts 'simultaniously'. As the title implies, though, it's something of a novelty record. It's also a step towards an insular world of solo musicianship which is arguably antithetical to jazz's group/audience dynamic. Miles Davis's association with Sly Stone at the end of the 60s was a more serious engagement with multitracking - Miles played extensively on
There's A Riot Going On and tried to transplant Stone's ethos into his 70s fusion albums. Sly obliterated the concept of time and space ("I make time" was his catchphrase through this period) - he recorded constantly with whoever was around, piling up mountains of overdub-saturated tapes. Ultimately though, Sly's expansion of time was based on detachment from reality and massive, massive drug use - it wasn't strong enough to support a new offshoot in jazz, and Miles eventually ran into a dead end. He had drug problems of his own, of course, as did Bill Evans. Part of the reason for jazz's failure to keep pace with the musical innovations of the 60s was that heroin had knocked so many of it's greatest innovators into a pit of insularity that they couldn't get out of. While pop culture raged outside, they preferred to stay home, with an audience of true believing jazzers, jacking up and having conversations with themselves.
Jazz is an antique in modern music - anything that isn't teeth-achingly 'retro' is confined to the experimental margins. It's a shame that the tradition of real-time real-space recording didn't make it's way into the 21st century, in a form that contemporary musicians can access without 'going jazz' and noodling all over everything, because doing computer music on your own is often quite isolating. I've argued with friends of mine that the webspace built up around electronic music is a new kind of virtual 'real-time real-space', where ideas get shared around and developed, and people negotiate musically with one another, but it doesn't cut any ice with real jazz fans - for them, people have to be in the same room at the same time, none of this 'virtual' bollocks. And like I say, I've got sympathy with that - even the biggest web evangelist knows deep down that it's not a substitute for real human contact.
I really wish that some of the Jazz innovators had made it to Jamaica in the late 60s and early 70s when reggae/dub was at it's most fertile - they could have reconnected with Jazz's roots as popular dance music, and learned how to combine great musicians playing in real time with some of the most mind-blowing studio-as-instrument techniques ever invented. We could have had jazz quartets made up of drums, bass, sax and mixing desk... who knows where that would have lead? A massive, massive shame that those two strands never came together
(Sorry, mad rambling thread hijack even by my standards.)
