To what extent can I use a song for a published production?
<p>There's a particular song that I applied so many effects to that all of the lyrics and specific melodies are beyond recognition, but, if you were to listen to the two songs side by side, still has the overall same mood or tone, though not much more. </p>

<p>Am I allowed to use that in a production? I wouldn't be using "all" of the song exactly, but I would be sampling from the range over most of the altered version of the song. I know there are laws on directly sampling from a song and copying melodies, but I don't know what addresses altered versions of a song.</p>

<p>This would be a canonical case of copyright infringement. 
<a href="https://www.law.cornell.edu/uscode/text/17/106" rel="nofollow noreferrer">17 USC 106</a></p>

<blockquote>
  <p>the owner of copyright under this title has the exclusive rights to do
  and to authorize any of the following....to prepare derivative works
  based upon the copyrighted work</p>
</blockquote>

<p>and in <a href="https://www.law.cornell.edu/uscode/text/17/101" rel="nofollow noreferrer">the definitions</a> </p>

<blockquote>
  <p>A “derivative work” is a work based upon one or more preexisting
  works, such as a translation, musical arrangement, dramatization,
  fictionalization, motion picture version, sound recording, art
  reproduction, abridgment, condensation, or any other form in which a
  work may be recast, transformed, or adapted. A work consisting of
  editorial revisions, annotations, elaborations, or other modifications
  which, as a whole, represent an original work of authorship, is a
  “derivative work”.</p>
</blockquote>

<p>In other words, when you transform a work into another work, you are creating a derivative work, even if it is hard to tell what the original work was. You can read about <a href="https://en.wikipedia.org/wiki/Bridgeport_Music,_Inc._v._Dimension_Films" rel="nofollow noreferrer">Bridgeport v. Dimension</a> as an example of someone being sued for copying and modifying 2 second's worth, without permission. However, there is disagreement depending on which district you are being sued in, see <a href="https://fairuse.stanford.edu/case/vmg-salsoul-llc-v-ciccone/" rel="nofollow noreferrer">VMG Salsoul v. Ciccone</a> where the court held that 230 milliseconds of copying was a trifling amount not prohibited by law. Your description suggests that this is not <em>de minimis</em> use.</p>

<p>If there is no direct evidence of copying (such as your confession), the court will rely on "substantial similarity" to determine whether you copied someone else's work. You would really need to consult with an attorney specializing on copyright law and music, to get a professional judgment of whether your work is sufficiently similar to the original.</p>

music