The startup sound was one of the delightful things that made a Mac a Mac, differentiating it from the beige boxes and bargain computers of the past. Apple made great efforts to add unique sounds to new models as well. The crash sound of the Power Macintosh 6100, 7100 and 8100 was particularly amazing (unless you were hearing it for real, then, well, it sucked).
A software update in 2016 removed the startup sound and many users were deeply unhappy about the prospect of a silent Mac.
An update to macOS Catalina appears to have restored the startup sound, and all it takes is a simple Terminal command to enable it.
Launch the Terminal application and enter sudo nvram StartupMute=%00 in Terminal and hit Return. You will need to enter your password after hitting Return. If you want to remove the startup sound after re-activating it just use the command sudo nvram StartupMute=%01.
I can confirm that this works on my MacBook Pro (15-inch, 2018) but it reportedly does not work on all models. We’d love to hear if it worked for you in the comments below.
And if you’re interested in a little walk down memory lane, the video below showcases every Mac startup and crash sound.