“Digital sampling refers to a technique of taking a recorded passage from an already existing or recorded musical, spoken or other work and then adding it into a new recording.” 1
Interpolation is where an artist adds new material to a performance or recording of a previously existing piece of music, or re-records a melody instead of sampling it.
For example Azelia Banks “212”, adds a vocal performance to the chorus and music of the song “Float my Boat” by Lazy Jay.
Any of the instruments and sounds making up a piece of music. The elements of a song can be voice and piano for example. It could also refer to a riff, the chord progression, melody or rhythm of a song.
A section or piece lifted from any previously recorded music; the sample itself. One of the most famous and ubiquitous samples is the six second long “Amen Break” 2
General rule of thumb is: if you did not originally record it or write it, you must clear it. This does not typically apply to chord progressions and rhythms (unless overtly recognisable, then there may be issues.)
There is no leeway on time or length of sample used. Samples lasting points of a second to three minutes all have to be cleared legally.
“Get a license or do not sample – we do not see this as stifling creativity in any significant way.” – US Federal Court (6th Circuit Court of Appeals) 3
As always, it depends. Who are you sampling? How much of the original song are you using? Who will own the new work? How will royalties be split and accounted for? Flat fee, rolling fee or ongoing royalties? How recognisable is the sample? How is it used? Does the new song rely heavily on the hook, melody in the sample? What is the purpose of the final music the sample appears in – movie, TV, bandcamp self release? Did you use the sample already and are now trying to clear it at the last minute?
A number of factors will determine the cost of clearing a sample.
Regardless of length, a sample that is derived from another piece of music should be cleared through the appropriate legal channels and the cost of doing so is contingent on a number of variables.
Sampling is a fundamental aspect of modern music production, technically and culturally, and there is a legal framework on how to utilise samples without infringing on another artist’s copyright, but it can be very tedious and confusing to figure it all out.
There are plenty of copyleft resources for royalty free music and clips that are a search engine away, though the quality can vary by large degrees. Even so, one has to pay attention to the usage license being granted; some agreements require acknowledgement, or are for non-commercial usage only.