In earlier seasons its the real ed o'neill voice....but in later seasons he's making the voice up and it sounds fony, this kinda irritates me...anyone notice this?

It sounds like his voice was higher in the earlier episodes, but soon starts to get lower. I like the lower voice better.

Yeah, his voice deffinitly got lower. Maybe he was trying to get more into character? :D

After watching the first couple of episodes of season 1 it almost sounds like he's using a "gangster film" voice