The quintessentially English King's Singers, virtuoso a cappella male vocalists who came together at King's College, Cambridge, in the late '60s, have recorded prolifically and are approaching a catalog landmark of 100 album releases. Three box sets of five albums apiece are on the market, all with titles suggesting they represent best-of selections from among the group's repertoire. In no case is this so; all the boxes are simply repackagings of extant releases, each representing the group's work on a different label. This one is drawn from the group's recordings for RCA in the early '90s, whose psychedelic graphics emphasized the experimental aspect of the group's work. The Singers were clearly looking for new directions during this period, and the music has an experimental flavor as well. While there is a representation of each of the main legs of the Singers' repertory -- part song, pop, and Renaissance polyphony -- each appears in unusual guises. This intonationally flawless group is never dull, but some of the techniques and arrangements here tend to work at cross purposes with the music. The German part songs on the Nightsong disc, for instance, have a fundamentally sober tone that the group has a hard time catching, even though the Romantic theme of night represents a typically smart programming idea. On the Good Vibrations disc the Singers bounce off mostly American popular songs that were complex to begin with -- the title track, or those of Paul Simon, for instance -- and this doesn't work as well as their usual artful elaboration of sentiment into colorful floating soap bubbles. Two of the five discs are devoted to songs of the rock era, one to Renaissance music (by Josquin, not as well suited to their modern Mannerism as the madrigals in which they have generally specialized), one to German part song, and one, perhaps the strongest of the quintet, to a mixed bag of love songs from all eras. King's Singers fans may have missed these discs, and none is disappointing, but the buyer looking for a general King's Singers collection might do better with EMI's The King's Singers Collection.