I have FiiO E7 & E9 desktop Amp that connect to my PC via USB cable. I want to know if connecting this amp using USB cable to a USB hub and then connecting the USB hub to my computer will have any negative effect to the sound quality?

Quote: lol, THanks. I thought it is a filter that can limit highest volume like some mp3 players' function, kind of set a ceiling.  

Quote: Will it reduce the volume of my music? Or just reduce the very high onboard announcement volume from the captain that may damage my IEM and my ears.  

Anyone know what is Airline attenuator for? And how does it work