I use Audio1 all the time now. I've used it so long, I've grown accustomed to it and now can't understand the Normal sounds.
Audio1 stretches out the tones longer and seems to give them more "character". I'd rather hear "weeeeeooooooweeeee" than "we, oo, we". I've found that my gold test ring has a much different sound in Audio1 (ferrous sounds). The pitch of the sound seems to increase more at the end of the travel than if it's a pulltab. Lots of hours spent scanning between good and bad known targets in my backyard coin garden. The slower you go, the more it draws out the sound and helps you determine just what's in the ground. If you hunt wide open IM-16, you will hear the low growl of iron often, but if you hear a good tone mixed in, scan a little slower and see what's there. Sometimes it's just a nail, but sometimes it's a coin with a nail.
I was hunting a ballfield the other day and came across a spot where someone had apparently set off a pipe bomb or something. There were pieces of cast iron that sounded a lot like a nice quarter. After digging a few of the pieces, I got to noticing that if I slowed waaay down and rescanned, I could hear the iron growl at the edges of the good tone. I quit digging the cast pieces and still found quite a few quarters and dimes in the same area.
With Audio1, it seems I can scan faster in some areas. If it starts to make a noise, I backscan over it slower. Sometimes Audio1 will limit the high frequency response unless you're going slow. Audio2 and 3 seem to stretch out the notes much longer and you'd have to go really slow to allow the high pitch sounds to come out.
Normal seems to have too short of a response. It goes blip beep blip instead of oooweeeeeeeeeooo. If you do the "wiggle" over a good target, it's hard to get it to shut up usually, which is good. For me at least.
I wish there was a way to post .wav files on this board. I have some recorded using my HP Ipaq pocket PC with a earbud type headphone taped to the microphone input. It actually sounds pretty good.
HH - Rhoderman