@timotimo: Turning it on or off is not what we mean by adjusting the volume. We want a more fine-grained control, such as a slider, to adjust it so that we can hear it but it doesn't hurt our ears.
Adjust volume
i agree- not only you can't lower it but it also partially mutes the volume of anything else you have paying
If using Chrome you can use this extension to manage each tab's audio level: https://chrome.google.com/webstore/detail/volume-manager/abnhonfioiokelhdappjknfaannlncac
https://support.chess.com/article/318-how-do-i-turn-off-sound