This tool will allow you to reconstruct the Fletcher-Muson equal loudness curve according to your own (or your partner's) ear. You will be constructing a single Fletcher-Muson curve at the reference tone's frequency and amplitude. Start by playing the reference tone. Then play the current tone. Then adjust the gain slider such that - to the listenting ear (your or your partner) the gain of the two tones is equal. You may need to go back and forth between the two tones a few times. Once you believe the tones to be of equal loudness, click "record gain value". You can then click "get new freq" to continue with the experiment with a new tone.