I've been using a PD-150 camera with a mono lapel mic that records to channels 1 and 2..

I just finished reading something from Jacob Rosenberg about always mixing down to mono for voice.. Now I know I am recording mono and it shows in Premiere as 2 channels, but should I use Audition and downmix it to a single channel mono signal. Is their any benefit to this in post, I assume file size may decrease as a benefit..

Thanks

Unless a specific reason makes it necessary to take this extra step, then it is not needed or can be accomplished in an easier way depending on your editing software.
For example, if you set one camera channel lower to handle sudden outbursts from your interview subject, then you would need to do some modification in post-production to have a proper mono representation of the voice in the final product.
If on the other hand your interview subject has a very even volume and you set both camera channels to have an equal recording level, then there's no need to mix down to mono.
Even if there is a need to "mix-down", most software allows you to do this automatically, without having to take an extra step.
In Vegas, you simply right-click on the region of audio, select "channels" and pick the appropriate choice.
A mono file will occupy half the file space, but that's usually not a consideration in editing, especially when you're talking about the difference in size between audio and video files. It could make a difference if you're e-mailing or transporting the files obviously.

Thanks for the reply.. I wasn't sure if it was easier to manipulate a voiceover in a single mono signal over a L+R mono signal..

Thanks again

patrick

It depends on how much flexibility your software allows when working with two-track files. In some software it is additional work to edit and manipulate a two-channel file that contains the same audio on both tracks. In other software this represents no extra burden to work with a dual-mono versus a single track file.
If you currently are having to go to extra mouse clicks and effort to manipulate a dual-mono track, your software may have a command or setting that can be engaged to eliminate this burden.