No we don’t recommend you use ultrasonic with headphones at all. Here’s why.
Headphones and earbuds make it too easy to damage your ears with excessive volume, even if the audio is audible. Most people I have observed using them use them at far too high a volume to be considered safe or healthy.
With ultrasonic subliminals, it becomes even easier to do this because you can’t consciously hear the audio. Even if you carefully set the volume, it is easily possible in many cases to accidentally bump the volume control too high or too low.
I do include instructions for how to set and use them, but that is because I know some of you will disregard this and use them anyway. It is best to play your ultrasonic subliminals on speakers.
Therefore, don’t use headphones and earbuds for listening to ultrasonic subliminals.
Posted in: Hardware Questions (Speakers & Headphones)