I have also noticed this on loud parts during guitar sessions the Zoom H4n via heaphones sounds very agressive, thin, sharp (hissy) and is very uncomfortable to the ears - long term listening can probably damage your ears even at low volumes. On the other hand Sony has pro approach very like studio finish - frequency is very balanced across the full range. Zoom H4 is not even worth talking about; to describe this is that its lost in somewhere in space !! Now, I can see why Sony is expensive.