For 35$ a year, I would very much expect there to be a volume button on the synth audio. Maybe it's a browser issue, but I cannot find a volume setting anywhere. How is this not already a feature?
Thanks for your feedback! Currently, you would just adjust your device volume to adjust the volume of the synth audio. I will pass this request along to our developers though, to see about having a separate adjustment for just the synth audio. We track votes and try to add the most requested features first. We will keep you updated on any developments!
Sight Reading Factory