You literally cannot find a worse pair of speakers on the market. Any $15 pair of desktop comp speakers blow the imac speakers out of the water. Like literally anything on sale at Futureshop beats them in sound quality. They sound like a CRT TV integrated speaker from the 80s that your gramma left on all day at her house.
Also, clean and flat? Those are the exact opposite words to describe the sound. It's a distorted, tinny whine that would, as a curve, look like a bell curve centered about 3/4 of the way up the register, with zero low end whatsoever. They're the least flat thing you could buy. And the "clean" you're hearing is the absence of 75% of the sound.
Just think about what you're saying for a second. We're talking about something that is less than 2 inches in diameter, yet it's several feet away from your head, pointing downward against a table of effectively random material and thickness. My headphones have a bigger diaphragm and they're right up next to my ears.
It is not physically possible for quality audio to be produced in these circumstances. It's plain ridiculous to claim it is. I guess you're comparing to other integrated monitor speakers, but that's sorta like comparing different flavours of cheeze whiz when Camembert is on sale for 75% off.