why is it that on some records, sound terrible??

Mostly your setup. Use something like the MintLp cartridge setup tool to minimize tracking errors throughout range of travel. Some of the problem may also be pressing and recording issues.

Sounds (no pun intended) like your cartridge isn't set up properly. Different music very conceivably would be affected to differing degrees, which would explain why some records seem not to have the problem.

Regards,
-- Al

I second the Mint tool. Best 100. I've spent in Analog.

well this is the problem, I just bought the new GNR album on vinyl and as the record played the sound got worse. BUT where i am confused is if i bought on a nat king cole record it plays very nice all the way through.

now with that said i am in the process of doing re-set up the TT because i haven't touched it in about 2 and years, adjusted the VTA and the Tracking Force.

I am going to run a quick comparison and i will report back soon.

Thanks for your help

Could be cartridge alignment. When I align mine, using the Linn template, I check the alignment both at both outer rim and interior to get it right.

Another common snafu is dirt/dust can accumulate on the stylus as the record plays, particularly if the record was just cleaned and is still damp and sound deteriorates accordingly until deposits are removed.