Crossfeed

[WalkGood]

I think it depends on which stereo enhance you are talking about, for some DAPs its just presets and there are some real good VST plug-ins for pc’s that have various controls. Regardless it’s firmware or software that modifies the width of the stereo signal and very similar to crossfeed. Typically the adjustment can be made for low, mid and high frequencies separately with good software. The separation of the frequency-bands is achieved by means of linear-phase FIR-filters.