The speaker grade class A, B....

Please note that for amplifiers, "class A" refers to the bias of the transistors. IOW it's primarily a technical, not a quality, term.

Unfortunately, I don't know the world's No1 speaker model, frankly I don't think there is a "No1". Regards

There are MANY exceptional speakers. They KEY to designing a great system and finding audio nirvana is system synergy - choosing components that work well together.

Finding the perfect speaker is sort of like dating - you need to audition a lot of them to determine what is best for your room and your ears.

Good dealers are paramount to meeting these two goals - by working with a dealer, or knowledgable individual you can cut down the trial and error costs and create a system that will be magic for YOU. It usually boils down to pay now or pay later. With a dealer you pay a little more up front, buying used you end up with more invested in trial and error and lots of time playing the guessing game.

..."Any website tells us or audio review grade speaker from 1st to bottom line in the world. Price of speaker can not tell us performance of speaker."

Yes, there are review sites and magazines; like "Stereophile" and "The Absolute Sound," that will rate speakers as well as many other components according to their "opinions" or some magazines will give out awards or editors recommendations. These issues are usually the Buying Guide Issue, or Editors Choice Award Issue.

Audiogon is also a great source for info, if you search the Archives. In addition you could do a search for other Online Review sites like; Stereophile, Positive Feedback Online, 6moons, AVguide, and dagogo.

Good Luck!