spectrum analyzer shows flat line nothing moving
A flat spectrum means the browser is not receiving audio. Allow microphone access for the site, pick the right input in the browser and check the…

Spectrum Analyzer Lead at Sound Test
Harvey Finch is the Spectrum Analyzer Lead on the Sound Tester Audio Team. Audits real-time fast Fourier transform (FFT) spectrum mapping and audio visualizer rendering accuracy.
Harvey Finch is the Spectrum Analyzer Lead on the Sound Tester Audio Team. Audits real-time fast Fourier transform (FFT) spectrum mapping and audio visualizer rendering accuracy. Contributes open-source digital signal processing tips on GitHub. On Sound Tester he answers Spectrum Analyzer questions, including flat displays, permissions and reading peaks, and reviews how each result is drawn.
A flat spectrum means the browser is not receiving audio. Allow microphone access for the site, pick the right input in the browser and check the…
If sound plays but the mic fails, the adapter or plug type may not carry the mic. Check the adapter supports a 4-pole TRRS plug and clean the…
If Discord hears you but the game does not, the game is using a different input device. Set the same mic in the game and allow microphone access.
Crackle for viewers usually comes from CPU load or sample-rate mismatch. Match all devices to 48 kHz, lower the stream quality and update Discord.
If the iPhone stopped asking for microphone access, the site was blocked once. Open Settings, Safari, Microphone, set it to Ask or Allow and reload…
If the browser never shows the popup, the site is blocked. Click the lock icon, set Microphone to Allow and reload.
After sleep, the audio service or driver can fail to restart. Restarting Windows Audio fixes it for now, and disabling fast startup or updating the…
Safari needs microphone permission for the site and sometimes a click to start audio. Check Settings, Websites, Microphone.
If only WhatsApp has no mic, the app permission is off. Allow the microphone in app settings and clear cache.
Self-muting is often caused by an inline mute switch, an app option or exclusive control. Check the cable switch and the app settings.
Each answer is written by the specialist closest to the topic and checked by a second team member. How we verify answers