You're almost right ...
Although it is true that not every Mac had it's own startup chime, and the chime did evolve over time, you are a bit muttled with respect to why, in what models and when.
The original Macintosh startup chime sounded different because it was based on an 8-bit, 22 kHz DAC. The chime remained pretty much the same until the 16-bit DACs and A/V models of Macintosh emerged in the early to mid-1990s. The chime was enhanced by adding more notes to the chord. The chord was still the same. The difference aurally between the standard 16-bit DACs in the Quadra series (and others with 16-bit DACs that came after) and the ones in the AV series was due to the DSP in the AV models. The DSP added spatial effects (reverb, sustain, etc.) to the chime. The other models lacked this DSP, so the chime 'sounded' different.
Since that time, and the time of the Power Mac, the chime has remained the same on all Macintosh models.
I think this rumor is unfounded. But, who knows what Steve will decide in the end.
Doraemon said:No. Not every Mac model had its own startup sound.
The startup sound evolved over the years, starting with a simple beep on the original Macintoshes, a multi-tone variant on the Macintosh II and SEs and a bass version on the late 68k models. The late Centris and Quadra models already featured the startup sound, which was also used on most of the PowerMacs (another variant of the bass startup sound) and is still in use today. The only exception were the first PowerMac models (6100, 7100, 5200, 5300, 8100) and the Twentieth Anniversary Macintosh.
On models with lousy speakers (like the PM 4400), the same sound might have sounded a bit different, but in most cases it actually was the same.
You can check out all startup sounds in MacTracker.
http://www.mactracker.ca
Although it is true that not every Mac had it's own startup chime, and the chime did evolve over time, you are a bit muttled with respect to why, in what models and when.
The original Macintosh startup chime sounded different because it was based on an 8-bit, 22 kHz DAC. The chime remained pretty much the same until the 16-bit DACs and A/V models of Macintosh emerged in the early to mid-1990s. The chime was enhanced by adding more notes to the chord. The chord was still the same. The difference aurally between the standard 16-bit DACs in the Quadra series (and others with 16-bit DACs that came after) and the ones in the AV series was due to the DSP in the AV models. The DSP added spatial effects (reverb, sustain, etc.) to the chime. The other models lacked this DSP, so the chime 'sounded' different.
Since that time, and the time of the Power Mac, the chime has remained the same on all Macintosh models.
I think this rumor is unfounded. But, who knows what Steve will decide in the end.