Why are my headphones buzzing whenever I run my game?

Original Article ↗ Hacker News Discussion ↗

Overall reaction to the story

  • Many readers enjoyed the “CSI-style” debugging narrative and found it almost cinematic.
  • Several appreciated that the author not only diagnosed GPU-related buzzing but actually fixed it in the game and shared a concrete optimization (partial texture readback).

Electrical noise and buzzing: how it happens

  • Consensus that the buzzing is electrical noise/EMI from high GPU/CPU load coupling into the audio path, especially over USB power or motherboard audio.
  • Coil whine and power-supply transients often correlate with specific on-screen actions (hovering UI elements, moving cursors, opening menus, high FPS).
  • People report similar issues going back decades: mouse movement or scrolling causing audible noise on built‑in sound cards or laptop speakers.
  • Several note that modern systems are better than 90s hardware but the problem still appears, especially with cramped layouts and poor grounding.

Debate over DACs and the Schiit Modi

  • Some say they’re “not surprised” a Schiit Modi is involved, citing past measurements and teardown critiques (USB power noise, soldering, unusual amp designs).
  • Others strongly defend the brand, noting improved engineering in newer models and years of trouble‑free use.
  • Several argue the real issue is bus‑powered USB, not the specific vendor; a well‑designed DAC should filter noisy USB power, but that costs engineering effort.
  • Discussion shifts from “DAC chip quality” to the whole analog chain: power supply rejection, grounding, and amplification matter more than raw THD+N specs.

Mitigation strategies discussed

  • Use external DACs/interfaces powered separately from the PC; best is optical (TOSLINK) or other non‑electrical links.
  • Avoid USB‑powered audio when possible; use dedicated DAC power inputs, filtered USB power, or powered hubs.
  • Separate audio gear onto a different outlet or circuit; some report big improvements moving off the same UPS as a gaming PC.
  • Other tactics: ferrites/common‑mode chokes, line filters, isolation transformers, optical outputs on motherboards, and better grounding (three‑prong chargers, lifting grounds on some studio monitors).

Game-engine specifics: picking texture vs spatial queries

  • One commenter questions using a GPU “picking texture” instead of a quad/octree for hit testing.
  • Others explain its advantages: perfect alignment with what’s rendered, O(1) lookup per click, simpler to implement for a 3D-under-the-hood isometric game, and negligible overhead if only a small region under the cursor is read back.
  • Clarification that each pixel holds a single entity ID like a z-buffer; non-pickable entities simply don’t write to it.