Noise Sharpening is one of the best DSPs in general, and both average users and audiophiles could greatly benefit from having a slider for this in the app.
Neutron Music Player uses this and it's a big reason for people to use that music player over others like Poweramp. (most google play reviews mention the sound quality there and some directly mention noise sharpening)
Here's a famous foobar2000 component for this DSP, for example:
http://foosion.foobar2000.org/components/?id=delta