Change Volume Quietly
When you change the volume on some Macs, the machine can make a fairly pleasant audible sound. But that particular sound can be annoying or disruptive in certain scenarios.
That’s likely why there’s a little-known and handy “silent” volume switching option in macOS.
Try it for yourself: just hold shift while you press the volume up or volume down keys. Note that using this shortcut will do the opposite if your Mac doesn’t make a sound when switching the volume.