I have tried to listen the ultrasonic version on headphones (connected to phone) but I don’t hear any sound. Is it ok like that?
On the same phone I have tested on Frequensee:
- on zero volume, the 20khz remains below -80db
- on the max volume, the 20khz rise up to -40db
I believe I have to set the volume somewhere in the middle…
I really would appreciate your experience regarding this,