Addition to Julie's comment about high frequency hearing loss: We also can hear "rich"tones, ones that have a range of tones, more easily. Lots of female voices don't have much "richness," are rather thin, which makes them even harder to hear. Men's voices tend to have a range of tones, so are easier to hear for that as well as their deeper (lower frequency) sound. People with great singing voices have lots of richness, so are easier to hear. The other big problem is that many of us can hear sound, not necessarily well, but know that someone is speaking, but have a very hard time understanding the words: discernment. This is a separate problem, one that tends to sneak in as we age. I have a real problem with discernment and wonder if it isn't partly due to the fact that I haven't heard clearly for decades as my hearing got ever worse, or how much of it is simply my age (nearly 80). Yesterday I was on a Zoom call with about 15 others; one fellow had a very deep voice that wasn't rich at all, so all that I heard from him was a general rumbling sound. Zoom is frustrating in that the sound from the crummy little mics we often use, plus some video is so poor that speech reading is hopeless.