Hi all. I have downloaded a file that has test tones from 15hz to 80 hz They rise one at a time and the whole thing lasts for about 5 minutes. Trouble is, my sub plays the 15 hz tone and I can hear it. I can hear all of them. I thought I was not supposed to be able to hear them below about 25hz. Oh before you swoon about in amazement of my powers, the rest of my family can hear them as well. Is this normal for one of these tests?