A spate of jazz festivals has kept area fans busy recently, but here comes another one: a five-night showcase of Washington-based talent at d.c. space. Leave it to the fest's sponsors, District Curators, always in the vanguard, to come up with a mixed bag of traditional and new sounds, young artists and established veterans, group performances and solo acts, and even some reggae for unwinding at evening's end.

Saxophonist David Waldo of Come Out Swinging, which opens the event on Thursday night, says "mainstream of the '80s" is a good description of the quintet which he helped form several years ago. "Walking the tightrope," he explains, "doing a little bit of the free stuff and then coming back, all within the same tune."

Then there is trumpeter Webster Young, whose sextet will conclude the series on Monday, July 5. Young got in with bassist Nap Turner, pianist Gus Sims and others at Armstrong High in the late '40s, was advised by Miles Davis "to make New York" and went on to record with Jackie McLean and John Coltrane. "It took me a while," he reminisced from his home in Adams Morgan, where he teaches trumpet, "but, you know, when you're in New York you work with everybody."

The Perry Contecchio Trio will follow COS on Thursday, Alex Coke and his woodwind quartet will split the bill Friday with the Tim Chambers group, solo saxist Jim Sivard and the Carl Grubbs Quartet are on Saturday, solo guitar by Mantuila Nyombo at 7 p.m. will precede the fireworks and Yahya's Harmolodica will follow them on Sunday, and Young will play at 8 and 10 on Monday with Nyombo on during intermission. Reggae will take over at midnight Friday, Saturday and Sunday with, respectively, the Lionhearts, Spliff and Black Sheep. Performances are at 10 and 11 except where noted otherwise. For more information call 783-0360.