THERE IS THE danger in experimental rock music of going too far; of trying to fuse too many different sounds or trying to incorporate too many independent effects. The inevitable result of over-stepping this peculiarly defined boundary is an abundance of noise, and a paucity of music. The many accomplishments of Traffic, for instance, were greatly obscured by the group's stubborn determination to embody special effects in its music.

Family-perhaps the best of the English groups that has followed Traffic's lead in experimental rock-was in Boston Thursday night with Savoy Brown, but their appearance was limited to one song. Electrical troubles with the group's keyboard and percussion instruments caused an hour and a half delay, and the eventual cancellation of their performance at Northeastern. But in Family's only song. "The Weaver's Answer." there was a brief glimpse of the vitality that characterizes this singular group.

Family's music lacks a dominating force. Within the group there is no one musician who overpowers, who eclipses the talent of the group as a whole. There is rarely one extended lead, but rather several-on different instruments-that are carefully inter-twined. Through variation, Family achieves a final sound that is full, yet evenly distributed. And herein lies their success in experimentation.

Family's talent is founded on its ability to unobtrusively incorporate a variety of instruments and styles into a single thrust. The group has employed 15 instruments-including woodwinds and brass-in combination on its three albums. New instruments are introduced in moderation, and this moderation holds for styles. Whereas Family's first album, Music in a Doll's House, , was primarily high-pitched in the Traffic genre, a gradual trend toward more restrained, more cohesive music is evident in their recent work. The progression has lead finally to a blend of country rock, English blues, and traditional rock on an album released last month, A Song For Me.

Family has been together since 1967, but remained relatively unknown until this year. Ric Grech and Jim King left the group last summer, and Grech went on to play bass for a widely publicized, but short-lived coalition known as Blind Faith. The foundation of the group-singer Roger Chapman and guitarist John Whitney-remained, however, and they created a new Family. They eliminated Grech's cello and King's oft-times superfluous saxophone, and supplanted them with vibes and an electric flute.

The retention of Chapman was most important. His voice's range is comparable to that of Stevie Winwood, late of Traffic and Blind Faith. Chapman draws at will on a nasal, resonant, almost English country twang that rolls words and phrases in a wholly distinctive way. Chapman's voice is important because, in Family's disconnected lyrics full of pauses and doubled over phrases-this quality provides a means of converting lapses and repetitions into an air of powerful expectation. This, in turn, transmits a particular excitement.

THE unstructured lyrics belie Family's move away from traditional rock, away from the strictly metered words of The Band. The Buffalo Springfield, and The Beatles. There are instances (especially on the second album, Family Entertainment ) when this disconnection seems to force words into the time of the music. But Family's music is one in which the final meshing of unconventional elements is in itself effective, so that this forcing of words is strangely appropriate.

Family's end product-considering the degree of experimentation-is amazingly balanced. Where Traffic failed in maintaining continuity, Family emerges unscathed. This continuity drifts over Family's wide range of music; the integrity of experimentation remains un-abused. Indeed, as the group has progressed, its music has mellowed and its mastery of coordinating different sounds has become complete.

Family is certainly not a great group in the overview of rock music. But for what they do-for the excellence they achieve in a genre that is based on unhesitating experimentation-they are exceptional. And tomorrow night, when they play a benefit concert at the Boston Tea Party, I suspect they will prove just that.