pa_volume is a simple tool to set the remembered volume level of pulseaudio clients. It requires module-stream-restore to be loaded (which is usually the case) to function. When called without arguments it shows all the known clients (running and non-running) and their remembered volume level. To set the volume level pass it the name of the client followed by the volume in pecent.
pa_volume paplay 50.1
will set the volume of paplay to 50.1%.
pa_volume
will list all known clients and their rememebered volume level for each channel.