When parents warn their children about the dangers of rock 'n' roll music, they usually refer to gross lifestyles and the glorification of drugs and sex. Older folks shudder at the "noise" and rant about bands whose only reason for such perversity is to sponge a few bucks off the unsuspecting youth of our nation.

In short, they describe the Tubes.

The Tubes are bizarre, even by rock standards, but their act contains an unabashed enthusiasm and a fairly high-class mix of music and theater that distinguishes them from some of the other weirdos frequenting the same territory. Also, it's clear that our nation is not the only one shelling out shekels to be corrupted by San Francisco's version of the "The Rocky Horror Show."

The band's latest album, "The Tubes Live" (A&M, SP-6003), is a two-record set recorded at London's Hammersmith Odeon last November. Judging from the crowd reaction, Tubeism has spread across the Atlantic to the world of punks and Robert Morley.

There's a lot to be said for "The Tubes Live." One thing is that the group has improved about two thousand percent musically since its first release and now seems tight and confident. Another is that they have song titles that may be classics of the genre in and of themselves: "White Punks on Dope," "Don't Touch Me There," "Mondo Bondage" (my personal favorite), the prophetic "I Was a Punk Before You Were a Punk," "What Do You Want From Life." True grit. Finally, as a rock 'n' roll album, "The Tubes Live" is the closest thing to straight shooting they have ever attempted.

The major flaw, however, is one that cannot be rectified because it's inherent in the Tubes' live act. The bald fact is that when it comes to a Tubes concert, you had to be there.

For those holding tickets, the Tubes will be here Friday night for a show at the Warner Theater. A Tubes concert is not a Tubes live album by any stretch of the imagination.

No album can convey the sight of lead vocalist Fee Waybill marching around stage on a four-foot platform shoes and throwing fake dope into the audience.

No record can project the general strangeness of their presentation. Nor can any disc truly capture the blend of theater and thunder that the Tubes do better than any other act.

"The Tubes Live" has gaps because Lord knows what's going on during things like the "Crime Medley." While the band rips through the themes from "Dragnet," "Peter Gunn," "Perry Mason" ("A Town Without Pity," also done recently by Ronnie Montrose on his new solo album) and "The Untouchables," one can only sit and listen to the sirens and crowd noise. The same blank appears during the "Drum Solo" two songs later. It's obvious that the boys in the band are not just sitting around watching Prairie Prince and Mingo Lewis hit the traps.

On stage, the Tubes are a mixture of "Let's Make a Deal" (here, best heard in "You Got Yourself a Deal"), "Hair," "Star Wars," and Fellini's greatest hits. Previous Tube records have nearly dropped dead because the ensemble was not musically up to the task of carrying all eclecticism. "The Tubes Live" almost does it, but not quite.

Even the purposely tacky cover art and the sticker that announces that "certain vulgarities are uttered on the track "What Do You Want From Life" and between songs on sides 3 and 4" are not as tongue-in-cheek as the actual stage performance.

However, the members' names, especially Sputnik Spooner (guitar and vocals), Re Styles (vocal on "Don't Touch Me There"), and Waybill and Prince, are easily the equal of monikers like Sid Vicious, Jimmy Rotten, Stiv Bator and Cheetah Chrome. And the Tubes' material is better.

Probably the best perspective with which to listen to "The Tubes Live" is to consider it the cast recording from a wild party. It's not bad on its own, but one must have attended to truly understand.