or loop some pink noise to burn them in?..
If you really want to burn in headphones, just get a playlist of mixed variety genre of music you like and set to a bit above normal listening levels. Let it play for a day or two if you really want to. Alternatively you could just use them as normal, but whatever works for you
Edit: here are some helpful resources as well
https://www.szynalski.com/tone-generator/
That playlist almost seems like it’s oriented towards measuring dacs
Thank you but there is a another popular method it using a web tool like Headphone Test Online - Headphone Check which is also a perfect way to check any headphone responses for free.
I found Audio Check almost a decade ago and have been using it for anything audio (testing) related. He really provides an excellent service with all of the audio check tools, test tones, and other useful measurement tools. You can even test your hearing level to see how high or low of the frequency spectrum you can perceive sound.
In this hobby, and in my humble opinion, it is certainly one of those sites worth backing to keep it going and to give credit where credit is due. Hope some of you find this as helpful as I did!