Pick a source. With the microphone, use headphones — through speakers the microphone hears them and it howls.
What you are hearing
When you speak you hear yourself two ways at once: through the air, which is what a microphone hears too, and through your skull. Block your ears and the skull path is trapped in the ear canal while the air path is shut out — your voice goes boomy and muffled at the same time. That is the occlusion effect, and this is it applied to a recording.
- 0 — open. The audio passes through untouched, bit for bit.
- A touch. Roughly the difference between a recording of you and you.
- Half way. One plug in, or hands cupped over the ears.
- 100 — plugged. Foam earplugs, pushed in properly: the low mids stay, the consonants are 30 dB down, nothing above 4 kHz survives.
Every setting is trimmed so the level of speech stays put — the knob changes the shape, not the volume — and the trim is shown on the display. The curve is a fit to the published acoustics of a plugged ear, not a low-pass with a name: how it was chosen.
Web-only: the output is hard-clipped at −0.2 dBFS so a hot microphone cannot send full scale into your headphones; the plugin has no such stage. The knob is ramped over 50 ms, the same as the plugin. Drop an audio file anywhere on this page to load it.