Does anyone know of a source for unimpeachably public domain bluegrass music? I know this can be really tricky, since often the original recording may be in the public domain, but subsequent mixes, or even the song itself may not be, and I want to get this right.

I'd imagine that one can find some buy-out music in the appropriate style for a reasonable amount and therefore be guaranteed trouble-free. Because as you said, even if the song is public domain, what about the performers?

Jewelbeat is well worth a look - 0.99c per track, albums from $9.99 - JewelBeat Download 99¢ Background Music (http://www.jewelbeat.com/store/downloadresults.php?sTxt=bluegrass)

You DO NOT want "public domain" music.

You want buyout licensed music.

Two different things.

The latter gets you a formal license to use the music in your projects - which is what protects you from copyright violation claims and potential lawsuits.

Most of the major libraries have stuff in the "bluegrass" category.

There's lots of public domain bluegrass, but the arrangements, performance and recording still might be copyright. Band-In-a-Box ( BIAB, PG Music Inc. - Band-in-a-Box, RealBand, and more (http://www.pgmusic.com/) ) affordable, easy for non-musicians to use, is one of the best kept secrets in movie music. It can generate automatic tracks for video. One thing BIAB does well is Bluegrass (and jazz). There's a set of royalty free BIAB BG with arrangement rights which either comes with the version you buy or separate. You arrange and voila! I'm not affiliated. A very basic example from me: Mail Fail - YouTube.

Does anyone know of a source for unimpeachably public domain bluegrass music? I know this can be really tricky, since often the original recording may be in the public domain, but subsequent mixes, or even the song itself may not be, and I want to get this right.Are you looking for the music or an existing recording of the music? Have to be careful because while music published before 1922 is in the public domain, that applies to the melody and lyrics, the music itself, and NOT recordings of the music. If you perform, or hire musicians to perform, and make your own recording of Stephen Foster's "My Old Kentucky Home" from original sheet music published in the 1800's you have no copyright worries. But if you get hold of a recording of that music made in 1910, THAT SPECIFIC RECORDING of the song could well still be in copyright and to use it you'd need to clear it. The copyrights on music and on recordings of music are totally separate and governed by different laws, durations, and dates. Virtually every recording ever made is still in copyright unless it was either created under circumstances where it didn't gain copyright in the first place (recorded in the US by the Federal Government with taxpayer funding would be an example) or has been explicitly released in the public domain at some point in time by the copyright owners. You might be able to turn up something like that with a search of the Library of Congress or Smithsonian archives.

These styles are even trickier because so much of it was never written down. So the rights if the composer run for (here) for 70 years after death, so you have to find out who wrote it, who performed it and who recorded and distributed it. Tough to get right 100%. Even when you think you are right somebody could pop up and say they were involved and want a cut!

On a personal note band in a box and the others produce formulaic music that most musicians can spot a mile off. Worth remembering that some instruments just give themselves away, finger picked banjo being a really obvious one!