A small band with orchestral quality is playing for dancers and listeners Wednesdays at Rosslyn's Top O' the Town. Last night, fronted by vocalist Jacquie Schmitt, the group was playing Sam Nestico charts of the '50s, a book that the arranger fashioned before becoming Count Basie's principal writer for the past two decades.

Schmitt's alto with full low register and instrumental-like legato was as creamy smooth as Johnny Hodges' sax on a medley of torch songs that included "When Sonny Gets Blue." Yet for "Wonderful World" she was as brassy as trombonist Dave Steinmeyer's accompanying growl.

Instrumental numbers were characterized by tight section ensembles and stand-out solo statements by a front line that also included the now clean-open and now raw-muted horn of trumpeter Jimmy Lay and the articulate baritone, tenor and alto saxes of Bill Schremp.

Variety was given the program by such choices as "Sam's Boogie," "Bells of St. Marys," "Night Train" and "Alexander's Ragtime Band." Pianist Morton Langstaff drew from a long association with Nestico in tying it all together, and solid underpinning was provided by bassist Tom Williams and drummer Chip Clemmer. This is a swinging band that deserves to be heard.