"I'm pretty new to recording and mixing. I've been listening to other recordings more critically since I got my system and one consistent thing I've noticed is that the bass, bass drum, and lead vocal are always panned dead center. I never thought about this before, but I just wonder why that is, and if anyone has done anything different with them?"

You may be too young to remember recordings that were done in the early days of stereo. Back then anything and everything was tried. You might hear the whole band in the left channel and just the lead vocal in the right channel. Some of it was really bizarre. Somewhere along the way the convention of putting the bass instruments and vocal in the center evolved. Some of this was for aesthetic reasons, but there was a practical side as well. Not everyone had stereo, and stereo recordings weren't always collapsed to mono in ways that gave both the left and right channel a fair shake. Consequently, you could end up listening to a recording with little or no audio from one of the channels. Even when the radio stations and record production plants got it together there was still plenty of opportunity for it to get screwed up at the final stage by the listener. Many people who bought the first "stereo" systems thought they were just getting two speakers and didn't understand that different things would come out of each speaker. Sometimes they wouldn't even hook them both up. Those were the days. Oddly enough, it sounds very similar to the struggles we are going through now with surround sound recordings and playback.

Another reason engineers started panning the bass drum and bass guitar to the center is because the low frequencies benefited from having twice the amplification and twice the speakers covering it. Try it yourself sometime. When you pan the bass to one side you do lose a little power in the low end. It just doesn't sound as full. And if the listener happens to be closer to the speaker without the bass in it the whole recording might sound really wimpy and disjointed. At least that was the thought process back then.

You may want to listen to some old recordings from the 1950's and 60's to hear some of the things that were tried. Just because we do things a certain way these days doesn't mean we got it right for all people all the time. If you think you have a valid reason to pan something one way or the other feel free to try it. I know a few engineers who do pan the bass and bass drum very slightly off center, just to open things up a little bit. There are rules, but then there are no rules. Some of the best recordings are done by people who know which rules to break and how, where and when to break them.