Massive and poorly mixed sound, generally weak lyrics and solo efforts more often than not indistinguishable from the aggregate marred the 3 1/2-hour pop production at the Warner Theatre Saturday night. It was an entertainment that was enthusiastically if not judiciously received by the crowded house. The beat was largely the thing and, in fact, the concluding set by the dashiki-clad vibraphonist Roy Ayers and his group was so dominated by rhythm that one was nearly mesmerized. The acrobatics a la Jimi Hendrix of Ayers' hip-swiveling lead guitarist and a six-foot-long tree-branch flute offered momentary visual diversion.

Tom Browne, a player who has been heard to advantage in acoustic formats, opened the tedious evening in a context of boiler-factory percussion that afforded him reasonable justification for aiming his trumpet at its top range and all but swallowing the mike with the horn.

So overwhelming was the volume generated by Lonnie Liston Smith's entourage that the musicians apparently found it necessary to employ steamer trunk-size monitor speakers in order to hear themselves. Smith, in dark glasses and a sequined shirt ablaze with reflection, held forth at center stage from behind his cloth-draped pulpit of an electric keyboard assemblage like some hip church organist. His feature on the baby grand had the instrument cranked up into amplified distortion, a shame because the electronic overkill all but blew away the rough-and-tumble blues voicings.