it depends on how you are getting the audio out of the laptop versus the iPod
In both instances, it is being played thru iTunes out the computer. Plug the iPod in to the computer, select the iPod as the Source in iTunes and click Play.
Are you asking about the headphone (1/8th inch) jack on both the iPod and laptop? In that case, there would not be a difference.
Sorry, but there would probably be a significant difference as you are using two completely different sets of hardware (Computer and iPod) to process, decode, amplify and send out to the speakers.
If you were getting audio from the dock port of the iPod, you might experience a difference.
Again, it will probably be significantly different as you are again using completely different hardware.