You’ve probably noticed that when you adjust the audio volume on your Mac, there is a quacking or clicking sound accompanying the action. This sound is intended to confirm that you are indeed changing the volume on your Mac. However, this sound can be annoying, especially when you’re wearing headphones. Fortunately, on most Macs it’s easy to silence the quack: simply hold down your Mac’s Shift key while adjusting the volume. Voilà, no quack.
Note that this might not work with a few third-party keyboards, and if you’ve re-mapped your Mac’s keyboard.
Bonus tip: by default, your Mac’s volume can be adjusted in 16-step increments (those white squares in the volume window that pops up when the volume is adjusted). If you hold down the Shift + Option keys at the same time, you can now adjust the volume in 64-step increments (one quarter step per square). This allows you to fine-tune your Mac’s audio volume output. Perfect for us obsessive-compulsive types!