Using 2 5G instances (Sort Of)

[JackOfHearts]

You're right maniac360 (Sort of )
I was actually asking if its ok that I hear ultrasonic faintly through earbuds, an hour or two...

It's ok but not recommended because you could damage your ears doing so. Because you could raise the volume too much without noticing it.
Some people do that though but I would not, it's risky. Plus if you have sensitive hearing or tinnitus it'll getting stronger with time. You are not going to damage your ear in one month but maybe with 1 or 2 years.

I mean playing ultrasonic with earbuds, you should only listen ultrasonic through speaker only.

Or are you asking that you can hear the ultrasonic faintly through earbuds which would mean that you are either playing it with the volume too high or that you have an exceptional hearing (you can ear ultrasonic, usually younger people can do that).
Either way don't play ultrasonic with headphone/earbuds. Unless you very very very sure about what you are doing and you don't slip up.