Here's a dynamic range test of the DR-60D.
http://www.fileden.com/files/2007/9/22/1451533/Mower%20and%20room%20render.mp3The recording was made with an MS pair of Sennheiser MKH series mics.
The first 30 seconds are of a lawnmower (rated at 70dBA) recorded at a distance of about 1 metre. It's LOUD. The second 30 seconds use the same gain settings to record the sound of a barely audible clock in a quiet room (but in daytime rather than night, which might have been quieter).
You can listen to this two ways. Either play back the first loud part at what seems to be the volume you'd expect to hear from a motor mower just in front of you (as if you were using it). Then when you get to the quiet bit, can you hear the clock - should just be possible - and can you hear any system noise?
Or, when you get to the second part, play it back so you can just hear the little clock, like I just could in the room for real. You have to listen hard to hear it tick once a second. Do you hear any system noise when the clock can only just be heard? Then play the first part - is it then painfully loud? (That's my experience).
My view is that this recording shows that this combination of mic and recorder has a dynamic range which equals that of the human ear - from loud to soft - without you being aware of system noise.
The jury is out - you decide!