The secret history of the Macintosh startup chime

Science · Published 1 November 2026 Swipe more like this →

In short: For decades, the Mac startup sound was more than just a pleasant tone; it was a diagnostic report. From software-generated beeps to secretly snuck-in synth chords, this auditory symbol tells a story of engineering triumphs, hardware failures, and a designer who refused to let Apple change his work.

The Macintosh startup sequence serves as an immediate feedback loop for the machine's health. Before the operating system even loads, hardware tests run to ensure the system is sound. A successful boot concludes with a chime and a visual symbol—historically the 'Happy Mac' icon designed by Susan Kare in the 1980s. Conversely, failures trigger distinct warnings: 'Chimes of Death' or beep codes for older models, and a 'Sad Mac' icon accompanied by hexadecimal error codes to pinpoint hardware issues.

The evolution of the chime reflects shifts in technology and creative rebellion. Early Macs used a simple 600 Hz square-wave beep programmed by Andy Hertzfeld. By the 1990s, sound designer Jim Reekes created the iconic 'bong' using synthesizers like the Korg Wavestation EX and Oberheim Matrix-6. Reekes famously snuck this C major chord into the ROM chips without permission because he was annoyed by previous tri-tone sounds; when Apple discovered it, he refused to change it.

Modern Macs have seen a complex journey of silence and return. Starting in 2016, new models shipped silently, but macOS Big Sur re-enabled the chime in 2020. This newer version is an F major chord—a pitch-shifted variation of the classic F-sharp major chord used from 1998 to 2016. While the 'Happy Mac' was retired as a boot icon in 2002, its legacy lives on; it was later repurposed as the Face ID icon for iPhone and iPad.

Technically, the boot process has moved from Old World ROMs (1984–1998) to New World ROMs, then to UEFI, and finally to a dedicated boot ROM on Apple silicon SoCs. These transitions dictate how the system verifies firmware signatures and launches iBoot, ensuring that by the time you hear the chime, the hardware has been thoroughly vetted.

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