Tip: If you run `pip uninstall audiocraft` it should render an interactive confirmation prompt that explains which files it is about to remove, this should help to understand where the library was installed (of course you don't have to confirm the prompt, just press Control-C or answer "No" to the prompt once you have your answer).
Disregarding the tip above, determining where the library was installed requires a bit of context, for example your platform (Windows versus UNIX) and the fact that newer pip releases default to "pip install --user" when not running with super-user privileges, whereas older pip releases did not default to "pip install --user".
Assuming you are using Linux and using an up-to-date pip release and you ran the "pip install -U audiocraft" command without super-user privileges, then the library was most likely installed in ~/.local/lib/pythonX.Y/site-packages (where X.Y is the version of Python that was used by the pip command you ran).