Si estás usando bocinas activas, (autoamplificadas), tienes que usar el Line para que no se sature el audio al amplificar. The footbed was so hard and uncomfortable on my hand I had to return them. They sound great for that application and I am told that my voice comes through loud and clear. Should I use the smaller ones so they fit in ear canal further, or the larger ones so they are snug?! Ive been able to use this twice now. 5" thickness. I’m a teacher and school is out for summer, but I can’t wait to wear them next school year. I was concerned about something in the "airpod" category: - giving an "insecure" (like theyre going to fall off) feeling - not having good mic pick up, since these have even shorter mic "booms" (if you call call it that) than the air podsbut theyre comfortable and secure feeling and folks at the other end say they sound just fineso unless something changes, Im quite pleased and will buy another pair if this holds up They seems securely fastened to the wall. When hes not using them, he puts them in their case.