The out-of-head localization achieved that way increases the listening comfort noticeably in contrast to conventional stereo headphone listening with its in-head localization of all sounds.
Most can edit music, apply effects and filters, adjust stereo channels etc. with waveform editing views and many are freeware programs without any limitations.
Stereo amplifiers usually have a common control for gain and frequently bass/treble and when switched to bridge mode will automatically track each channel identically.
