I am the fountain of affection

this is going to sound odd; I hear the 15 and 17 fine, and with 'depth' (ie, I actually hear 3 tones that integrate into one). I can hear the 16 faintly, and only one tone - however, it sounds as though it's at the same volume from about 50% and volume higher (lower than that and I don't hear it at all; the sound is pass/fail for me). I don't quite understand why I would be 'missing' the middle tone, so I tried it with audacity, and running the kHz higher and higher. I can hear clearly from 14 to 22 (haven't checked any further), *except* for pure 16kHz tones. I'm wondering if that possibly stems from my tinnitis; I know I have occasional problems understanding women's voices, from that, however I can't think why the tinnitis would block out the one pitch.