The Lettumplay benefit yesterday at the Ibex club brought together in an informal atmosphere, and sometimes in spur-of-the-moment combinations, many of the area's top jazz musicians, who contributed their time to raise money for this nonprofit group that, among other good deeds, brings music to prisoners, hospital patients and other shut-ins.

Pianist Eddie Hayter's Kashmir Jazz Trio opened with an across-the-spectrum choice of tunes from which a strong group identity emerged. Hayter's balance of silent space and crowded clusters of sound lent dynamics to "Waltz for Debbie" and "Blue Bossa." Drummer Tom Teasley's crescendos of hard press rolls invested "Don't Mean a Thing" with high drama. Roosevelt Coleman wielded a mighty upright bass.

"Imitation of a Freight Train," a solo harmonica offering by Phil Wiggins, huffed and puffed from a "think I can" crawl to a highballing clickety-click accompanied by a high lonesome dead-of-night blue wail.

Mary Jefferson in "You Ain't Had the Blues" stretched and bent syllables over the hand-clapping beat of her audience. Pianist John Malachi's solo "Back Burner" had saucy swing, broken-up tempos and a two-note Count Basie ending. Others performing at the crowded event were bassist Peter Keter Betts, drummer "Dude" Brown and vibraphonist Clement Wells.