The system tech needed pink noise for his transfer function measurement. Rather than use a proper signal generator, he searched YouTube for 'pink noise' and played the first result through the PA. It had 847,000 views and a comment that said 'great for tuning your system!' It was not great for tuning your system.

The YouTube video had been uploaded in 2014 at 128 kbps MP3. YouTube had then re-encoded it through at least two additional compression passes. The 'pink noise' was pink in the same way that a photocopy of a photocopy of a painting is art. The high-frequency content above 15 kHz was nonexistent — the compression had eliminated it. There were audible codec artifacts at 8 kHz. The level was inconsistent because the uploader had applied a fade-in and fade-out.

The transfer function measurement showed the system apparently rolling off 12 dB above 12 kHz. The tech applied +12 dB of high-frequency EQ to compensate. When actual music was played through the now-corrected system, the tweeters were so bright that the front row shielded their faces as if approaching the sun. The system hadn't been rolling off — the YouTube reference signal had been.

The measurement is only as good as the reference signal. Garbage in, garbage out, with equalization applied on top.

The Moral: Use a proper signal generator, not YouTube. SonaVyx's built-in calibrated signal generator produces mathematically precise pink noise, swept sine, and MLS directly in the browser — no compression artifacts, no codec losses, no YouTube comments required.