This tap contains audio tools and plugins that can not be added to main homebrew (no stable version tagged, no website etc)
Just brew tap david0/homebrew-audio and then brew install <formula>.
If you are using the official Ardour binary, Ardour will segfault if you try to use the GTK UI. This is because its not possible to mix two versions of GTK in the same memory space.
Use the Generic UI only instead (see the Ardour Manual for more information on that).
Try using the experimental (and not officially supported) Ardour Formula, which will build an Ardour version using the GTK stack provided by homebrew.
Any other LV2 host that is build via homebrew like jalv will also work fine with the GTK UIs.
Feel free to issue a PR adding additional formulae or improving the existing ones.
You can try to commit these formulae to main homebrew but be aware that usually each formula has some problems that make it not fulfill the minimum acceptable formula criteria (mostly head-only)