Norah Jones is the smooth-voiced 24-year-old daughter of the world-famous sitar player Ravi Shankar, a jazz-trained pianist who grew up in Texas, studied piano at the University of North Texas, cut her teeth playing in Charlie Hunter’s band, and scored a solo deal with the jazz-oriented label Blue Note, which retained the legendary jazz producer Arif Mardin to give his touch to her now platinum-selling, Grammy-winning 2002 album Come Away with Me. The LA-raised, 35-year-old Gillian Welch is a Berklee School of Music graduate who fell in love with the old-time sounds of the Carter Family, Stanley Brothers, and the Louvins, moved to Nashville with her musical soulmate David Rawlings, and helped spark a revival of the kind of country music that’s about as familiar on Music Row as Fischerspooner through her involvement with the Grammy-winning soundtrack to the Coen Brothers’ 2000 film O Brother, Where Art Thou? (Universal) and the subsequent D.A. Pennebaker documentary (and Universal soundtrack CD) Down from the Mountain.

On the surface, aside from a handful of Grammys, Jones and Welch don’t have much in common — unless, of course, you count Jones’s sultry cover of the Hank Williams classic "Cold Cold Heart." But in the larger scheme of things, the two are songbirds of a feather who flocked together last Saturday night at FleetBoston Pavilion for a low-key evening of pitch-perfect harmonizing, artful covers, and seasoned musicianship.

What makes Jones and Welch soul sisters is that their recorded work attests to the refreshing diversity of tastes among significant masses of music consumers — a diversity practically undetectable before the introduction in the early ’90s of Soundscan, a system that electronically tracks sales at most of the major retail CD outlets. More important, both Jones and Welch achieved commercial crossovers without latching onto a prevailing pop trend. So as disparate as their musical Muses might be, they made for perfect touring partners, a point that was underscored when Welch, the evening’s opening act, joined Jones on stage for some gorgeous harmonizing.

The differences between the two extended from influences (jazz versus country) all the way to instrumentation: Welch was backed by little more than her own acoustic guitar and that of Rawlings; Jones had the aid of a full complement of drums, upright and electric bass, drums, and two guitarists as she switched between piano and organ. But both proved adept at adapting covers suited to their own sensibilities, from Welch’s rendition of Waylon Jennings’s "Lukenbach, Texas" to Jones’s take on Cole Porter’s "Night and Day." And with no fancy stage sets, expensive outfits, or smooth stage patter to rely on, they came off as two of the more down-to-earth Grammy winners you’re likely to encounter. Not only did Jones accept a hot dog from someone among the capacity crowd, she actually took a couple of bites.

(Jeff Ousborne’s review of Gillian Welch’s new Soul Journey appears this week.)