I got it.
To all those wondering out there:
I initially burned it at 4x with TDK.
I popped up my actual Sega CD game (yes, I only have one, shame), no noises
Then I popped in Sonic CD (Burned, HP format), no noises
therefore I concluded that it must be the disc media
So I had another HP format CD, burned it (at 4x), and no noises
Plus I didn't even have to press detect disc, it auto detected it as soon as I turned the game on.