As first noted by Pingie, the startup chime which confirmed to users that the notebook had passed its Power On Self Test, is no longer.
Over the years the chime has changed. The first being a “bong.” Quadras brought in a chord composed in a C major on a Korg keyboard. It was pitch shifted a few times. Power Macs brought in an electronic jazz guitar strum. The 20th Anniversary Macintosh had a poppy remix of the classic bong as a tribute to the original Mac. But all Mac computers post the iMac G3 have had the same sound – an F-Sharp cord sound modulated from a PowerMac startup sound.
Apple has updated its support documents to confirm the change.
Previously, Apple's instructions for resetting NVRAM read:
Hold these keys until the computer restarts and you hear the startup sound for a second time.
They have since been updated to:
Hold these keys down for at least 20 seconds to ensure that your Mac completes the process correctly.
Will you miss the Mac startup sound or did you find it annoying?
Let us know in the comments!