For openSUSE Slowroll run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ecsos/openSUSE_Slowroll/home:ecsos.repo
zypper refresh
zypper install portaudio
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ecsos/15.6/home:ecsos.repo
zypper refresh
zypper install portaudio
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ecsos/15.5/home:ecsos.repo
zypper refresh
zypper install portaudio