Usage

For general information about overlays and using 3rd party ebuilds please refer to (webcached) http://gentoo-wiki.com/HOWTO_Installing_3rd_Party_Ebuilds

layman
Note than pro-audio is not in layman anymore.

The easiest way to get and update the overlay is to use layman. emerge -av layman As the layman ebuild warns you, you will not be able to add many overlays without dev-util/subversion. The pro-audio overlay is one of them. So if you haven't done so yet you should now:
 * install layman
 * install subversion

emerge -av subversion layman -fa pro-audio for layman 1.1: echo "source /usr/portage/local/layman/make.conf" >> /etc/make.conf
 * fetch the overlay list and add the pro-audio overlay
 * include in make.conf

for layman 1.2: echo "source /usr/local/portage/layman/make.conf" >> /etc/make.conf

for layman 1.3: echo "source /var/lib/layman/make.conf" >> /etc/make.conf

To update the overlay use layman -s pro-audio

If you encounter problems during update, first delete the old overlay layman -d pro-audio && layman -a pro-audio

Paludis
Paludis is the Other Portage Mangler location = ${ROOT}/usr/portage/local/proaudio master_repository = gentoo sync = svn://svn.tuxfamily.org/svnroot/proaudio/proaudio/trunk/overlays/proaudio format = ebuild names_cache = /var/empty mkdir -p /usr/portage/local/proaudio paludis --sync
 * paste it in /etc/paludis/repositories/proaudio.conf
 * and make the overlay repertory
 * don't forget to sync

SVN directly
svn co svn://svn.tuxfamily.org/svnroot/proaudio/proaudio/trunk/overlays/proaudio cd /path/to/proaudio svn up
 * to checkout the overlay
 * update

tarball
You can also download the overlay as an autogenerated tarball tarball