I came across a very early Jaco recording with muti-instrumentalist Ira Sullivan where Jaco is playing a Baritone Guitar. Check out Portrait of Sal La Rosa on Ira Sullivan's Myspace page: http://www.myspace.com/irasullivan

Jaco played in Ira's band for a few years and Ive hears some excellent live recordings but Jaco only appeared on one track of an acual Ira album. But he didnt play BAritone Guitar .....jaco played his custom made 5 string Acoustic bass guitar that had a high C. It might say baritone guitar but all it was was a regular bass with a high C added....its well documented that Jaco had this bass built but wasnt satisfied with the results.

Didn't the headstock break off of that bass?

Jaco did get a cool sound out of the bass, but it doesn't seem to get the punch and sustain that allows him to cut through so well.

From Ira's Bulletin on Myspace.com (which is how I found the recording):
New tunes posted with Jaco Patorious featuring Joe Diorio, Jaco Pastorious , Steve Bagby.
One night at a session for my Ira Sullivan album recorded in '76, Jaco showed up with a rare instrument, a baritone bass guitar that was just custom built for him by a fan. Although it sounded like a bass and he played it like a bass, it actually resembled on of those large acoustic guitars that you see played by the Mariachi groups. The opening harmonics set the mood.
Jaco gave his new baritone guitar it's first go on the tune Portrait of Sal La Rosa, and that tune went on the record.
This music was an example of the what we played every night at the Unitarian Church in Miami on Monday nights that allowed us as musicians to play free form and play in the moment from our stream of consciousness, or as Joe would say, from the right side of the brain.
The tuned was composed by guitarist Joe Diorio as a tribute to one of Joe's Art instructor, Sal La Rosa. Rythym section is Steve Bagby on drums with Dona Alias on Congas along with my Afuche Cabasa.

Didn't the headstock break off of that bass?

Jaco did get a cool sound out of the bass, but it doesn't seem to get the punch and sustain that allows him to cut through so well.

To be honest, I think the fact that he "did not cut trough so well" was very pleasant.

I love Jacos music more than anything, but this was great to hear as well.

From Ira's Bulletin on Myspace.com (which is how I found the recording):
New tunes posted with Jaco Patorious featuring Joe Diorio, Jaco Pastorious , Steve Bagby.
One night at a session for my Ira Sullivan album recorded in '76, Jaco showed up with a rare instrument, a baritone bass guitar that was just custom built for him by a fan. Although it sounded like a bass and he played it like a bass, it actually resembled on of those large acoustic guitars that you see played by the Mariachi groups. The opening harmonics set the mood.
Jaco gave his new baritone guitar it's first go on the tune Portrait of Sal La Rosa, and that tune went on the record.
This music was an example of the what we played every night at the Unitarian Church in Miami on Monday nights that allowed us as musicians to play free form and play in the moment from our stream of consciousness, or as Joe would say, from the right side of the brain.
The tuned was composed by guitarist Joe Diorio as a tribute to one of Joe's Art instructor, Sal La Rosa. Rythym section is Steve Bagby on drums with Dona Alias on Congas along with my Afuche Cabasa.
Yea I read it but I also have a cd compilation made up of early Jaco recordings made by hist best friends and there are several pictures and stories about that bass. It was simply a 5 string bass ....it did have a huge body like Ira says.....Jaco used this bass to warm up in the mornings and such.