For live sound this is mostly true, but for recorded music there can be artistic reasons to pan low frequencies to one side or another. (Just like there could

For live sound this is mostly true, but for recorded music there can be artistic reasons to pan low frequencies to one side or another. (Just like there could be artistic reasons to do just about anything.) It seems to be more common in electronic music rather than rock, and there certainly are jazz records where the upright bass isn't dead in the middle.