Originally Posted by Random_Kiwi

I don't get how a 45 is better than a 33?

If it's spinning faster, won't that mean more grooves per side, and more grooves mean spacing is closer together, which means inferior quality? I thought the less amount of info on a disc, the better...like a 6min track spread across one side of a 12" is going to have better quality than a 12" with 3 x 6min tracks on it.

It doesn't mean more grooves per side, because 45 speed 12 inches it generally only have 1 or 2 songs.

At 33/3 you can have around 25 mins of music per side
Whereas 45s normally have around 11 mins max per side even though they can accommodate more.

Most dance music tracks don't need the whole 25 mins of a 33/3 so they use 45 and spread the song across the whole side. - thus the greater space = greater quality like you said in your post.

Even if you can't actually tell the difference with your own ears, the science behind it all suggests otherwise.