A friend of mine needs a hearing aid. He got problems with it. The audiologist first tried an Universal IEM, later on a Custom IEM. In both cases he (the audiologist) drilled a second hole through the tip to avoid air pressure in the ear canal. I have never heard of a second hole in the tip of an IEM. Could somebody give me an explanation?
With kind regards, Artmon
Edited by Artmon - 3/5/11 at 1:50pm