Acoustic ring test for bullion — private, on-device
Install this app: tap the Share button
in Safari, then "Add to Home Screen".
dismiss
How to test: balance the coin flat on a fingertip (touching as little as possible),
then tap its edge with a fingernail or another coin, close to the microphone.
Your browser kept voice processing (echo cancellation / noise suppression) enabled on the
microphone — common on iPhone/Safari. Frequency readings usually still work, but ring
volume and sustain may be distorted.