system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How are musicians able to cover a song and not pay royalties, whilst sampling music means paying through the nose?
gpt
Copyright is complicated.

In a song there will be separate copyrights in: the sound recording, the lyrics, and the music. It is entirely possible that there will be separate copyrights within those (if, for example, someone licensed some music or lyrics for their own lyrics or music).

These are often owned by different people - particularly the sound recording (owned by the record producer) v the lyrics and music (owned by the composer/lyricist).

So if a musician wants to cover a song they only need permission from the copyright owner of the lyrics and music, whereas if they use a sample they need permission from the owner of the recording copyright as well.

**Except** in the US this a bit different - due to piano rolls.

In the early 1900s the US had a problem with a company with a monopoly over the "piano roll" market. Piano rolls were sheets of paper with holes punched out, which you could feed into a modified "player piano" and it would play the music on the piano (the holes telling the piano which keys to press when). In 1908 the company won a case in the US Supreme Court, which ruled that these piano rolls were not copies of the original music as they weren't human-readable. Meaning that the piano roll company could produce and sell copies of composers' music without paying any royalties (and they did, causing concern to composers).

Congress changed the law to make it clear that piano rolls infringed copyright, so needed a licence. But as a compromise they created the idea of a "mechanical licence" - meaning that copyright owners couldn't refuse permission to use their compositions - instead third party organisations could act as "collective licensing" agency. If the piano roll company wanted to produce a piano roll for a particular piece of music, rather than having to get a licence from the copyright owner, they could just pay a fee to the agency, and the agency was responsible for paying out to the composers.

But this only covers the copyright in the music - not the actual recording. So producing a cover song is relatively simple; you just sign up to a collective licensing body and pay the appropriate fee. Whereas if you want to sample you generally do need a licence from the copyright owner directly.