Avant-Garde A Cappellas Keep Bobbin’ Along : Singers: The group whose repertoire includes covers of Led Zeppelin’s “Whole Lotta Love” and Talking Heads’ “Psycho Killer” brings its unique vocalizing to the Coach House tonight in San Juan.

True to his calling, the Bobs’ bass singer Richard Greene speaks in the professionally modulated rumble that broadcasters strain for years to achieve. It’s one small recompense in the low-end singing job that never found the real-life respect that the early-’60s hit “Mr. Bass Man” promised.

Reached by phone in San Francisco last week, Greene admitted that it sometimes is frustrating to see his fellow members of the Bobs--Gunnar Madsen, Matthew Stull, Janie Scott and recent inductee Joe Finetti--getting all the attention with the lyrics and melodies, while he’s stuck with the tuba part. But there are advantages to holding the bottom spot on the Bobs’ a cappella totem pole.

“I don’t have to remember the words,” he said cheerfully.

The Bobs, for those not acquainted with them, are hardly your standard a cappella group, as attested by such song titles as “Let Me Be Your Third World Country” and “First I was a Hippie, Then I was a Stockbroker, Now I’m a Hippie Again” and their fearless voice-only covers of Led Zeppelin’s “Whole Lotta Love” and Talking Heads’ “Psycho Killer.”

Once described as “sort of a cross between Devo and the Mills Brothers,” the Bobs’ avant-garde vocalizing earned a Grammy nomination with their first album in 1984. They have since worked in collaborations with the respected, ground-breaking ISO dance troupe and the Oberlin Dance Collective, and have shared bills with a range of artists, from the Grateful Dead to the late Sarah Vaughan.

The Bobs’ press release maintains, “Without the Bobs, life as we know it on this planet would cease altogether and we would be plunged into unimaginable darkness.”

One needn’t stock up on candles and flashlights yet, as Greene says the Bobs have a busy schedule before them. Along with extensive touring this year--they appear at San Juan Capistrano’s Coach House tonight--they are working on a new album and have a PBS special with ISO in the can. The group is also developing a new show with the dancers, has done soundtrack work for an upcoming film titled “Sketches,” and Greene and his Bobs writing partner Madsen have been commissioned to write a piece for the Minnesota Opera New Music Ensemble.

This burgeoning artistic enterprise got its start in 1981, when Madsen and Stull decided to form an a cappella group after losing their jobs singing telegrams. Greene joined after “I read this ad they placed that said, ‘Wanted: bass singer for new wave a cappella group.’ So we had a little rehearsal together. We sang ‘Proud Mary’ and ‘Down by the Old Mill Stream’--not real exciting stuff. Then when I was about to leave, Gunnar said, ‘Oh, I have one more thing I want to try.’ And it was his arrangement of ‘Psycho Killer.’ That kind of sold us all on doing it.”

Greene and Madsen were soon writing together and are entirely to blame for “Banana Love,” “Food for Rent” and the Bobs’ other skewed tunes.

Their “Helmet” is about a fellow who feels safer viewing the world through protective headgear. “Johnny’s Room” is an evocative piece about a couple forced to stay in separate bedrooms on a visit to the girl’s parents. “But Then, a Week Ago Last Thursday” celebrates some simple joys: “I drove for hours and never hit one red light / I ate a day-old tuna sandwich and felt all right / Luck was mine.”

“Mopping, Mopping, Mopping” gives a new perspective to hurricanes with lines like, “She puts mascara on the eye of the storm.” The song, part of a suite about the weather, was composed for the Los Angeles Theater Center in 1985. “The Laundry Cycle,” composed for the Oberlin Dance Collective, is made up of five songs loosely based on doing the wash.

“I think we look at the world in a very normal fashion,” Greene maintained. Describing how he arrives at his song subjects, he said, “I try to keep myself reactive and observe what goes on around me and try to let myself be open enough to take whatever things I see and hear and do, let them go in and muddle around in there for a while and come out in whatever form that they want to. And I find it becomes easier and weirder as it goes along to not try to analyze the process, but just to let it happen.”

While the Bobs have made some inroads in gaining mass attention--with PBS shows, National Public Radio spots and an appearance on the Smothers Brothers show--the media hasn’t exactly laid palm fronds at their feet.

“It’s been more like potted ferns,” Greene said.

In the hope of finding greater exposure, the group is shopping for a record label with better distribution and financing than the tiny Great American Music Hall label that issued its last two albums.

Not that the Bobs are looking for a massive studio budget. According to Greene, “Some of the best and most fun stuff we have done has been at times like last summer when we did an album in Italy in eight days or so. It had to be done in a hurry, so we just said, ‘OK, so let’s just have as much fun as we can and not be hypercritical.’ And in many respects, it came out much better than the stuff we look at carefully. We’re going to try to record rapidly from now on.”

Their next album can be expected to feature such titles as “Drive-By Love” and “Synesthesia.” It also is likely to feature some of the tracks from the Italian sessions, a set of cover songs that have been released only in Europe. Among the results of those sessions were “Whole Lotta Love,” “Purple Haze,” “Come Together” and “Ring of Fire.”

Tonight’s Coach House show will be the local debut of the group as a quintet.

“Joe Bob Finetti is a great addition,” Greene said. (The Bobs are prone to adding a “Bob” to each of their names.)

“Joe Bob is another tenor,” Greene added. “We’re all tenors, except for my bass. He is much more of a jazz musician than the rest of us, and he’s also a consummate air percussionist--he sings drums.” The addition also loosens Greene’s role as a bass man, which he allows is already looser in the Bobs than it would be in most other outfits.

“With Joe often singing percussion, I don’t have to sing wall-to-wall rhythm stuff,” Greene said. “But the way most of the arrangements are, I get lots of room to improvise. I’ll often just improvise through the whole song. Being involved in the writing, I know what the structure of it is, so I can play with it a little. And I’m even doing a few leads now, with Gunnar singing bass.”

And wherever he’s placed on the clef, Greene says it’s a continual thrill to be in the midst of the Bobs’ voices. “When you hit that chord, whatever it may be, and it really pops and all the intervals are in the right place, there’s this great resonant effect. And it’s like making some sort of architecture constructed out of air.”

The Bobs play tonight at 8 p.m. at the Coach House, 33157 Camino Capistrano, San Juan Capistrano. A previously announced late show has been canceled. Tickets: $19.50. Information: (714) 496-8930.