Configuring Rivendell to work with ALSA
From Rivendell Wiki
RDAlsaConfig
The easy way to configure Rivendell to work with ALSA is to run the utility that now comes with Rivendell called rdalsaconfig. Run rdalsaconfig as the super user so that it can write the changes to the ALSA system wide configuration file /etc/asound.conf.
On an Ubuntu system you would run:
sudo rdalsaconfig
to run the command as the super user.
More Details
The complete details of how to configure ALSA to work with Rivendell are documented in the file ALSA.txt which resides in the docs/ folder of the Rivendell source tarball or in /usr/share/doc/rivendell/ALSA.txt on a system with the Rivendell package installed.
In brief summary, for Rivendell to work with alsa it requires an ALSA device with the name of "rd0". This can be configured by creating or editing the file /etc/asound.conf (or optionally .asoundrc in the home directory of the user running Rivendell) and populating it with the following contents:
pcm.rd0 { type hw card 0 } ctl.rd0 { type hw card 0 }
Note also that the user ID under which caed(8) runs (typically “rduser”) may also need to be a member of the group “audio”.
ALSA Resources
More information can be found here