Being a member of the rock 'n' roll faithful -- assuming it can be compared to anything else -- is like being a professional sports fan. You go to rock 'n' roll concerts like a fan goes to game after game. Sometimes, when your group looks as good on stage as they sound on records, you win. And sometimes, when the people who go with the sound you paid to hear turn into one big disillusionment, you lose -- and feel like a sucker for caring at all, knowing like the sports fan that they're out there for money and not for love.

So far this season on the Boston rock 'n' roll circuit the Unicorn Conference has staged two big names, big money concerts and the score is one-all. The first point, for good rock 'n' roll and fine, upbeat performance, was won by the Mamas and the Papas; the second was painfully lost to the forces of commercialism and bad taste by the Righteous Brothers.

You don't know what to expect from the Mamas and the Papas -- all you've seen of them is their picture in a bathtub on the cover of their album and all you've heard are stories about LSD arrests. There are four of them and they flew in from the Virgin Islands last spring with two enormous hits and a totally original sound. You walk back stage at the Commonwealth Armory expecting to find a completely flipped-out bunch, four curiosities who happen to sing nice songs.

They look the part -- Cass is unbelievably enormous, enveloped in a hallucinogenic turquoise chiffon muumuu. John Phillips, the group's leader and chief song writer, sits calmly sipping something out of a bottle which is swathed in purple velvet. Idly he wanders over to a blackboard and writes on it, "Love plus hate equals life. Fear plus hate equals power." Michelle is small and beautiful; Cass leans over and whispers to her, "You should have seen your pupils dilate just now." Michelle just smiles softly. They are enjoying themselves, but not at their audience's expense; beneath their antics, you get the feeling, is an intense and concentrated intelligence. That combination -- plus song writing and vocal talent -- gives them a tremendous built-in advantage over every other group (except the Beatles) in the business. As you watch them you are almost irresistibly tempted to ask them what their sleeping arrangements are, but refrain because you know they would probably tell it to you straight.

No one has invented a name for the Mamas' and the Papas' sound, which is just as well, since no other group could imitate and cash in on it anyway. The Righteous Brothers, on the other hand, are credited with founding a "school of rock 'n' roll, blue-eyed soul." You have to sit up close to verify that Bill Medley and Bobby Hatfield do indeed have blue eyes, but you could have sat anyplace in the Back Bay Theatre and figured out that the Righteous Brothers have about as much soul as Laurence Welk. And this is something not to be realized lightly by one who had devoutly kept "You've Lost That Lovin' Feeling" on her all-time-great list despite the disdain of more sophisticated patrons of the art.

Appearance is certainly never anything to be held against a rock 'n' roll star, but from the tops of their ducktail haircuts to the tips of their white buck loafers, these two look worse than any pair since the Everly Brothers. Bobby -- the little blond one who does that fantastic third "baby" in "Lovin' Feeling" -- kept calling tall dark Bill "eel" and "snake." The names are apt, but his voice gives you a few minutes when -- if you close your eyes or otherwise block out his perpetual smirk -- all can be forgiven. It is amazingly deep and seems to come from nowhere; the echo chamber you were always sure they used must be carried around somewhere in Bill Medley's throat.

But despite their sound and their songs, the Righteous Brothers managed to do something inexcusable -- they enjoyed themselves at the expense of their sell-out audience and make a mockery of whatever soul was supposed to go along with the blue eyes. They never sang a song straight, except for Hatfield's "Unchained Melody," which he only got to after a five-minute build-up of bad jokes. At one of the emotional moments of "Lovin' Feeling" Hatfield suddenly stopped singing and smirked, "Ooo, let me outta here." And in "Soul and Inspiration," in any case an inferior imitation of the first song, Hafiteld stopped before he came to the spoken "baby I can't make it without you" section and quipped, "Okay, bring out the Oscar." Maybe the songs embarrass him so much that he has to let you know how silly and cute he feels singing them. All right, but the Righteous Brothers claim to be the white interpreters of Negro soul music; the thought of James Brown, the quintessence of soul, being anything but absolutely sincere about his own music is absurd. These two don't interpret; they capitalize. They collect their $7500 per performance and make anyone who credited them with being honest musicians feel like a sucker.

Noticeably absent from their repertoire were their more recent songs like "He" and "Go Ahead and Cry," no doubt because it would have cost too much to fly in from Southern California the choir that accompanies them on those efforts. In fact, they have never had another song like "Lovin' Feeling." It was written by Phil Spector when the pair were recording for Philles. Since then they have worked for both Verve and Moonglow with a steady increase of choir music and cacaphony; if they haven't had a real hit for six months it's hardly surprising. Their latest release, "On This Side of Goodbye," is back in the old style, but is just another dull reworking.

It is ironic that the Righteous Brothers, who got their first big break (so legend goes) by doing a great warm-up act before the Beatles' Los Angeles performance of 1964, brought with them two warm-up groups who strove to outdo each other only in tastelessness. Nino Temple and April Stevens once had a hit with a sappy 1930's revival called "Deep Purple." They spent their time on stage making bad jokes about his virility and displaying her eroticism to the worst advantage. Gaylord and Holliday, a comedy team, did a wonderful parody of Sonny and Cher's "Bang-Bang" but the rest of the time contented themselves with reciting embarrassing racial jokes.

The Tag-Alongs

The groups who come along with the stars don't have an easy job at these concerts. They are found in several varieties -- some are young struggling unknowns, some are once-popular performers who can no longer draw their own crowds, some are provided at each stop by the show's local manager, and some (like those with the Righteous Brothers) come in a package with the star attractions. No matter who they are or once were, no one wants to hear them now. Audience reaction ranges from apathy and flickering applause to total inattention to occasional hisses. Ceci and the Chasers, the first group at the Mamas and Papas concert, have a pleasant, if slightly guitary sound, but they had to play with the house lights on, and absolutely no one in the vast smoky armory paid the slightest attention to them. Discovering later that they are earnest Tufts undergraduates makes you feel guilty that you, too, didn't clap.

Guilt and embarrassment, though, is what the rock 'n' roll faithful get used to -- embarrassment at being part of a crowd of 12-year-old girls (at some concerts) or of black-leather-jacketed toughs (at the Righteous Brothers). When you hear the music you came to hear, it's all worthwhile. But the other 75 per cent of the time, you wonder if you're crazy