ultrasonics on laptop

[Tiesto]

Can one just listen to a masked version to see effect

Yes definitely can. The masked version is just as effective as the ultrasonic.

Although from what I understand the ultrasonic is more versatile, you could play it while watching a movie, listening to music, and doing other things.

While with the masked version if there are other sources of loud noises that covered up the audio, it might reduce the effectiveness.