TTS Volume control

I’m using VoiceRSS for my text to speak processor, which I send to my Sonos speaker. I have a few rules that provide announcements first thing in the morning and in the evening. Recently though my wife has suggested I turn down the volume of the announcements in the morning, she’s getting up a little earlier that usual.

I’ve tried changing the volume with the usual commands; Kitchen_Sonos.sendCommand(10) & setMasterVolume(new PercentType(10)). Although they adjust the volume for any music playing, the announcements from VoiceRSS stay the same.

Any advice, is there another command I should be using?

This looks relevant

Thanks for that, very much appreciated.