What it is. Comparing the frequency response of two sound sources with your own ears — finding the balance difference across frequencies. In short: tuning the sound of your favorite headphones to match another pair.

Requirements. The key is being able to output sound to two audio devices from the current device at the same time:

• a dual headphone output (two jacks);
• wired headphones + Bluetooth at the same time;
• two different Bluetooth devices (headphones).

Preparation. Play the same music on both pairs simultaneously — make sure sound comes from both. Disable any equalization in the system, the app and the headphones themselves. Put the favorite (reference) pair on your right ear, and the one being tuned on your left (its volume will change during the test).

1. Calibration. In the Calibration card, press the balance button — pink noise will start. Set the L/R balance so the noise sounds exactly centered, at a comfortable volume. Press the balance button again — the balance locks.

2. Phase. Press the phase button (440 Hz) and adjust the phase so the tone is stable, comfortable and sits exactly in the center of your head. Press again — the phase locks.

3. Compensation Curve. Press ▶ and for each frequency move the green line up/down so the sine wave sounds centered in your head — equal on the left and right. Use the frequency navigation buttons. Accuracy is up to you — don't fool yourself.

4. Result. Stop the test, choose the equalizer type and number of bands below the chart, and press Match. Apply the resulting settings to the left (tuned) headphone in your own equalizer.