Richard - You hit on a good point that many poeple don't consider when evaluating projection systems, especially front projection.
When I got my Panasonic PT-L300U projector a couple years back the first thing I did was drag it into Myer-Emco in the DC area, hook it up to the same source that was feeding a $12,000 Runco and do an A-B comparison of the two.
Guys came in and commented a lot on image quality, but one of the things that struck me right away was that I couldn't hear the L300 at all. The Runco projector, with NO other audio in the room, completely drowned out the sound of the L300. Sales guys blew it off like it was no big deal, but a few guys actually put their ear closer and closer until they said they could hear the L300. About 5 inches from the projector, they could hear the unit over the roar that was the Runco.
That's noise that takes away from the film you are watching. A suspense filled silent moment with a 'WHHIIIIRRRRRRR' filling your ears loses a bit of the suspense for sure. You also can just pick up any big old speakers you want on sale at whitevan.com as you won't be able to even figure out what a noise floor is or what noise in the signal means.
Noise in the signal is status quo for some projectors and buyers need to be aware of this when purchasing.
The AE700 is noticably louder than my L300, but the image is also much brighter with better detail... I lived with the AE700 for a couple of weeks and didn't find it horribly loud, but definitely noticably louder.