Strange background noise through USonic earphones?

[andyste1]

Got my U11 yesterday and so far loving it, but when listening to music through the earphones I can hear a low frequency "rumble" during quiet parts, or between tracks. It's loud enough to be distracting/annoying even without the volume turned up. It's definitely the USonic feature as the rumble comes and goes as as I turn this on and off. Anyone else noticed this?

I also struggle with the fit of the earphones too, which constantly feel like they are on the verge of falling out, and that's just when I'm sitting down. I don't hold out much hope of walking around with them in. I never had any problems with the earbuds of my last phone (M8), so perhaps it's the extra weight of the U11 buds?

 

[Ben_70]

Yes, I've noticed it. Right after a song ends, I hear what sounds like a "rushing of air" noise. Then it stops a couple of seconds later. I believe this is the active noise cancellation doing its thing. I usually don't hear it during a song so it doesn't really bother me.
The buds fit well enough for me but I did have to downsize to the smaller tips included in the box.

 

[wynand32]

I'll have to listen for this the next time I use them. I haven't noticed anything like that up to now, or at least it didn't stick out to me enough that I'd remember it. It's been a week or so since I've used them, though.