The sound library is bigger than the app, and most of it is optional
Loops, instruments and legacy content are downloaded in full by default. What each part is, and how to remove what you do not play.
Music software on a Mac downloads its content library separately from the application, and the full library is enormous. It is also mostly optional: a producer who works with one instrument set is storing dozens of others.
Where the content lives
du -sh /Library/Application\ Support/Logic \
/Library/Application\ Support/GarageBand \
/Library/Audio/Apple\ Loops \
~/Library/Audio 2>/dev/null | sort -hMost of it is in the shared /Library rather than your own, which is why it does not show up when you measure your home folder and why the numbers surprise people who have already looked.
What each part is
| Part | What it is | Removable |
|---|---|---|
| Apple Loops | Prerecorded loops by genre | Yes, per collection |
| Patches and instruments | Sampled instruments | Yes, redownloadable |
| Legacy content | Content from older versions | Usually yes |
| Impulse responses | Reverb spaces | Small, keep |
| Your projects | Audio you recorded | No. These are yours |
Removing content the supported way
Logic has a Sound Library Manager under its main menu, which lists content by collection with sizes and lets you remove and redownload individually. That is the correct tool: it knows what a project needs and it can fetch anything again.
GarageBand offers the same idea more simply, and deleting the app does not remove the shared content, which is a common reason a Mac still holds many gigabytes of loops for software that is no longer installed.
Your projects are a separate question
Recorded audio in a project is not regenerable, and project folders with many takes get large. Bouncing finished projects to a stereo file and archiving the multitrack version to an external drive is the equivalent here of archiving video projects.
Common questions
Where are GarageBand and Logic loops stored on a Mac?
Mostly in /Library/Application Support and /Library/Audio/Apple Loops, which are shared rather than in your home folder. That is why measuring your own folder does not find them.
Can I delete the Logic sound library?
Yes, through Logic's Sound Library Manager, which lists content by collection with sizes and can redownload anything later. Removing content by hand risks projects that reference a missing instrument.
Does deleting GarageBand free up the loops?
No. The shared sound content stays in /Library after the app is removed, which is why many Macs hold gigabytes of loops for software that is no longer installed.
What in a music setup cannot be redownloaded?
Your own recordings and project files. Everything Apple ships as sound content can be fetched again, so those folders are the safe part to clear and projects are the part to archive.