An NBA crowd at Capital Centre will boo most anything: a referee with two legs, a lazy superstar, even Tiny, the unbearably cute mascot dachsund, if he doesn't hustle after his little rubber ball.

But it isn't every day that a crowd boos itself.

On Sunday when the attendance figure of 10,488 - nearly 9,000 less than the 19,035 capacity - was announced for the Washington vs. Cleveland playoff game, the crowd gave a nice round of boos for the folks who weren't there.

Bullet general manager Bob Ferry was still shaking his head and muttering yesterday over how a do-or-die, final game of a playoff series could fill only 55 per cent of the seats when identical games in Portland and Oakland were drawing 105 per cent of capacity.

"I don't know how to answer it," said Ferry yesterday. "It's the lowest playoff crowd we've ever had. It was a great 10,000 people that showed up, but . . ."

But where were the other 9,000 the Bullets admit they feel they should be able to draw in this "second season."

If nothing else, Washington fans will get a chance to atone for their non attendance this coming Sunday, and perhaps the Sunday after that, also.

The Bullets announced their playoff dates for the Houston Rocket series yesterday. After Tuesday and Thursday games this week in Houston (9:05 p.m. (EST) starting times), the Bullets play at home on Sunday (1:30 p.m.) and April 26 (8:05 p.m.).

The "if necessary" games in the best-of-seven playoff are set for April 29 in Houston (9:05), May 1 at Capital Centre (1:30 p.m.) and May 4 in Houson.

Those dates brought instant bad news yesterday for people holding tickets to the circus scheduled at Capital Centre on Sunday and April 26. The 11 a.m. and 3 p.m. performances on Sunday have been canceled as well as the only performance on the 26th, at 7:30 p.m.

The 7:30 p.m. third show Sunday is still in doubt. If the Bullets play a sixth game on May 1, the first two circus performances would be canceled with the night performance also still in doubt.

Purchasers of circus tickets were warned in advance that particular performances might be canceled by either basketball or hockey playoffs. Such dual scheduling in advance with circus and playoffs conflicting is not uncommon at large areans around the country.

Bullet officials were searching yesterday for reasons why this season's first two playoff games at Capital Centre drew 11,240 and 10,488, while last year's first two games against the same Calvaliers attracted, 17,988 and 17,542.

The Bullets biggest enemies on Sunday as beautiful spring weather and an afternoon of television that included all or parts of four NBA playoff games, two major golf tournaments, a baseball doubleheader and an old John Garfield-Ida Lupino movie.

"In the past there were no regional NBA TV telecasts," pointed out Ferry. "There would have been a blackout of all games, if we weren't sold out."

Nevertheless, Ferry was more perplexed than anything at the crowds which are embarrassing the Bullets by comparison with the other NBA teams in the playoffs this year.

"If the fans knew how much they affect the players, there'd be no question of sellouts," said Ferry. "There's nothing in the world like 19,000 people telling you how good you are. It's everythihg, like a chain reaction of electricity among the players. You can see it in their eyes.