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Frequency Spreading

Fan noise mitigation through asymmetric blade spacing and RPM offset, as implemented in the Mac Pro 7,1.

start: 2026.04.13, 15:50 · end: 2026.04.13, 15:50
status: In Progress

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· certainty: likely

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· importance: 5/10

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One of the most infuriating things about modern PCs, barring RGB, is the harmonic resonance of fans. That continually amplified jet engine sound while you're trying to think. It's been my mission for a while to free myself from this. I finally think I've found an ample solution, or rather taken on one from the 2019 Mac Pro 7,1. That is frequency spreading, which is technically just resonance avoidance via RPM offset.

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To Read

Foundational

Papers

Engineering Reference

Mac Pro 7,1 internals with GPU installed
Mac Pro 7,1 internals with Sapphire RX 6900 XT.
Mac Pro 7,1 rear view with case open
Mac Pro 7,1, rear view open.
Mac Pro 7,1 triple fan array with asymmetric blade spacing
Mac Pro 7,1 triple fan array, the blades use asymmetric spacing.

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