peppyalsa plugin was created during refactoring of the PeppyMeter application. Before the plugin was created PeppyMeter was using 'file' ALSA plugin. That plugin can output PCM data either to a file or named pipe. Unfortunately the plugin has some limitation - it opens a named pipe in a blocking mode. That means that if there is no reader running on the other end of the named pipe then audio player which is using 'file' plugin will be blocked. It will not output any sound.