Use this test to find which insertion depth gives you the flattest frequency response. Depending on how deep you insert them into your ear canal, their frequency response will change drastically. This test is of particular importance for earbuds. If the test tone sometimes disappears, or gets too loud, you know you have a problem, either with your hearing or your headphones. If your hearing is imperfect, this then means that your headphones are simply matched to your ears.
If your hearing is perfect, this also means that the headphones have a flat frequency response.
If the sweep keeps playing at your hearing thresholds, your headphones are matched to your ears. Our compensation only works at hearing threshold levels: turn your computer level down so that the test tone plays as quietly as possible. It embeds an inverted hearing sensitivity curve that turns it perceptually flat. With a prominent sensitivity bump around 1–3 kHz, humans are not good at judging flatness: frequencies in the upper medium range will always sound louder than what they are because of the increased hearing sensitivity. Frequency responses are measured using sine sweeps and special test equipment.
