Look up RIAA equalization on the web. Plenty of information. There are several tutorials with lots of math and curve plots.

As for whether it sounds better or not. Beats me. I have lots of records so I listen to them. I also have lots of CDs. I prefer the records but... My turntable, cartridge, pre-amp, etc. is of much higher quality then my CD stuff (currently).

Interestingly I am developing the opinion that, dollar for dollar, currently, the best CD reproduction out performs the best Vinyl reproduction. I've listened to truly stunning systems for both and the dollars to reach stunning for CD is, I believe, now below that(sometimes well below) that of vinyl.

YMMV, void where prohibited by law, pay no attention to the man behind the curtain, etc., etc.