A Broadway musical hit offering light-and-sound pyrotechnics; Concerning 'Cats,' there are few moderates

Believe it or not, ''Cats'' is controversial. That's an unusual state of affairs for a big Broadway musical hit. Judging by my own sampling, cat people love ''Cats.'' Among less partisan sectors of the populace, response seems to range from keen delight to puzzlement and annoyance. Confidential feline sources confirm that there are few, if any, moderates.

One recent visitor to ''Cats,'' a titan of TV tinsel, sniffed that ''it was a 20-minute show packed into two hours.'' (Call Growltiger to the barricades!) No one should know better than a talk-show host about galloping escapist inflation. Gratuitous as it was, the comment does reflect the extreme views that ''Cats'' can prompt. Nevertheless, audiences are packing the Winter Garden Theater and tickets are selling as far ahead as next April.

Furthermore, Andrew Lloyd Webber continues to occupy the catbird seat of show business. Mr. Lloyd Webber is said to be the first composer to have three shows playing concurrently in New York and London. ''Cats,'' ''Evita,'' and ''Joseph and the Amazing Technicolor Dreamcoat'' are running on Broadway; ''Cats,'' ''Evita,'' and ''Song and Dance'' adorn the West End.

''Cats'' opened here to mixed notices - a response Mr. Lloyd Webber has encountered before in New York. ''Evita,'' written with his frequent partner, Tim Rice, received a generally negative press. It then went on to win seven Antoinette Perry (Tony) Awards, including Best Musical, and has recently celebrated its third anniversary.

Though generally hailing it as a directorial triumph, almost all ''Cats'' reviews have contained reservations, some of them severe. One of the repeated objections is that the pop-music settings for T. S. Eliot's whimsical verses have been overwhelmed by visual aids and special effects.

The effects, including light-and-sound pyrotechnics, are nothing if not special and spectacular. They begin visually with the transformation of the Winter Garden into the semblance of a huge junkyard, seen from a cat's perspective. Piled higgledy-piggledy are cartons and tin cans, the rusting hulk of a car, bottles and bicycle parts, squeezed toothpaste tubes, broken records, old magazines, an enormous truck tire, and other detritus.

The make-believe of ''Cats'' doesn't end with its environmental scenery and incandescent razzle-dazzle. In a surprise transformation, the deck of a pirate ship suddenly erupts through the skyscape backdrop to create the setting for the fierce Asiatic battle of ''Growltiger's Last Stand.'' In the second big special effect, the cast assembles a locomotive from found objects (a la the stagecoach construction in ''Nicholas Nickleby'') for the tribute to Skimbleshanks, the railway cat.

Finally, in the climactic ascension scene, the great tire moves majestically forward to become a smoke-belching, jet-propelled spaceship. With Old Deuteronomy (Ken Page) and Grizabella (Betty Buckley), the fallen glamour cat, as passengers, the rocket soars to meet the emerging stairway up which she will climb to cat's heaven. This is the moment when designers John Napier (scenery) and David Hersey (lighting) reach for the stars.

Such are the spectacles wrought by director Trevor Nunn and his boldly imaginative colleagues. Yet who will deny the theater's right to spectacle? In an age of mind-boggling cinematic illusion, there is something to be said for the stagecraft that can bring off an extraterritorial encounter right in front of a live audience. ''Cats'' mixes the light-and-sound technologies of the times with old-fashioned showmanship in an entertainment made to order for the family trade.

Although the fantastical feline celebration lacks a plot, it offers an album of small stories and essays in verse set to music. There is also an overall theme relating to birth and death, redemption and transcendence, memory and the meaning of happiness. Part 1 of the show is subtitled ''When Cats are Maddened by the Midnight Dance.'' Part 2 is called ''Why Will the Summer Day Delay - When Will Time Flow Away.'' The subtitles suggest the moods of ''Cats.''

Most of the show's lyrics come from the 1939 Eliot collection, ''Old Possum's Book of Practical Cats.'' Mr. Nunn and Richard Stilgoe supplied additional lyric material for the prologue, taken from the unpublished ''Pollicle Dogs and Jellicle Cats.'' In a Playbill note on the text, Mr. Nunn writes that ''some of our lyrics, notably 'The Marching Song of the Pollicle Dogs' and the story of 'Grizabella,' were discovered among the unpublished writings of Eliot.'' Growltiger's mock-opera aria appeared in an Italian translation of ''Practical Cats.''

Mr. Nunn adds: '' 'Memory' includes lines from and is suggested by 'Rhapsody on a Windy Night,' and other poems from the 'Prufrock' period. All other words in the show are taken from the 'Collected Poems.' ''

Finally, a few more observations on the environmentalism of ''Cats.'' Perhaps in part to make up for the nine down-front rows of seats removed to accommodate the extended Winter Garden stage, the management has installed two onstage seating sections - one on each side of the playing area - with room for 27 spectators. The onstage patrons are thus deep in the ''Cats'' environment. But the make-believe also embraces the audience as a whole.

During the performance, the cats democratically fraternize from time to time with members of the public fortunate enough to be along the aisles or runways. At intermission, people swarm up the ramps onto the stage, something very rare in a New York theater. The patriarchal figure of Old Deuteronomy holds court from his tire throne and - in a world where cats may acknowledge their admirers - signs autographs. What else?