AMERICAN men are tied in knots. Suits are still prim, proper, and dark, but what are these broad, garish bits of cloth passing as neckties that escape from their button-down collars?A revolution is under way in American neckwear that threatens to make obsolete the old familiar polka dot, regimental stripe, and sober diamond patterns. Even the Wall Street yellow power tie - remember? - might now be forgotten. Once neckties, like people, had standards, and everybody agreed on what was horrible. But now, what is a good tie? What is a bad tie? Nobody seems to know anymore. As one way of measuring the confusion, the Washington Post conducted a tie test to survey taste and quality. Pollsters asked 82 people to study 10 ties - five from quality stores, five from street vendors - and separate the expensive from the cheap. Labels and prices had been removed, but participants were able to feel the fabric and examine the ties. Even that hands-on approach didn't help much, as evidenced by the frequent response: "This is really tough." So tough, in fact, that 66 of the 82 participants - a remarkable 80 percent - rated a $67.50 Armani geometrical print as a street tie. Only one person correctly identified it as top of the line. At the same time, several respondents guessed that a $3.33 floral number from the street was the most expensive in the group. Since American men annually spend $1.2 billion on ties, the new creations may have some of the more trend-conscious among them by the throat. But the strain will be worth it if ties, like women's hemlines, eventually prove to be an economic forecaster, as in the past. During the Great Depression, wide ties with bold graphics were also the rule. By this economic indicator, a return to quieter tastes will not only be good news for most men, but for the nation as well. Some people can hardly wait.