Stereo audio has two channels (left and right) that create a sense of space. Converting to mono merges these channels into one. Average mode sums both channels at equal volume. Left/Right mode keeps only the selected channel.
Mono conversion is essential for audio compatibility. Many devices (phones, Bluetooth speakers, radios) play in mono. Mono audio is also easier to analyze and process, and prevents phase cancellation issues when played on mono systems.
Mono audio has a single audio channel, while stereo has two.
Better compatibility with mono devices and simpler processing.
Average mode preserves all content, just without stereo separation.
When left and right channels are out of phase, they can cancel out in mono.
Yes, completely free.