Listening with just an earbud

Is this effective listening with just an earbud?

What do you mean, with one earbud or using earbuds?

Listening just with one side, left or right.

I don’t think one earbud is sufficient because the underlying technology has different information in both ears. Ultrasonic is different though. Right?

Would be cool if it worked with only one though even if not as effective.sometimes cant have both earbuds in or on ears at work because it appears rude and need to be able to hear other people talking.

Simple search turned up this:

Of course that was before Ultima. But then again…

You MIGHT be alright with Q. You need both with Ultima. I recommend both with all, though.