Yes, the ext spkr jack on the back is made to be used with an external speaker that can be driven by the higher power available there. The front jack is for use with headphones. It is cut back in power so as not to blow out your eardrums.
Larry
thanks for the info... i was thinking that was the case since I noticed a difference in audio level when switching an ext speaker from one jack to another. ext speaker to the rear jack it is !!!