echo cancellation test

https://mynoisesuppressioncheckfinder.wordcanopy.com/posts/why-a-noise-suppression-check-matters-for-clear-online-communication

In the echo cancellation test, you record your voice in an empty room and play it back through a speaker while the microphone is still live, to see how well the software strips out the reverberation and delayed repeats; a clean result leaves only your original speech with no hollow after-ring.