I Make Kitty Scared

Picture Snow White or Sleeping Beauty frolicking in the forest, singing songs with the little animals and the sound of her beautiful voice causes the critters to gather around and gaze upon her lovingly. The birds are inspired to sing quaint little harmonies and the world is all a'bliss.
Pretty little picture, yes, but alas, it's make-believe. Unfortunately, my reality is much to the contrary. My cat is neurotic and he hates to hear me sing. Whenever I sing, he goes freaking ballistic and turns into an attack cat!
We've known for some time now that my oldest cat, his name is Cheeba, is a little… different. He has allergies, so every spring and fall he gets a skin condition that causes him to lick himself until his fur falls out and he gets open wounds that scab over that cause him to itch and the rash spreads. He does get better with the medication he has to be on, but because of his neurotic licking behavior, it seems he always has a bald spot somewhere, and of course he also coughs up some nasty hairballs the size of sausage rings all the time.
I've had him since he was a kitten, about 5 years now. He's always been a very loving and sweet, if not pathetically needy, cat. But recently, I've noticed him becoming quite agitated with me when I start to sing. Now before I leave myself open for wise cracks, let me just toot my own horn a little by saying that I CAN sing, what's more I can sing well. I have been in a number of choirs, quartets, duets, and I've even been known to do some live solo performances from time to time and have to say I've never experienced people fleeing, throwing tomatoes on stage, or cats bellowing from the alley in anguish. So I just don't understand why he goes so berserk whenever I sing… why does it affect him and not my younger female cat?
My husband sings (heh, or tries to) and gets no response from Cheeba though he could be sitting less than a foot away. My daughters sing sometimes yet never provoke him, but the moment I start to sing he suddenly runs in from the far ends of the house and relentlessly whines and howls until I stop singing. If I'm singing in the shower, he'll bang on the door incessantly while whining and howling until I stop. If I'm standing up, he'll attack my leg. If I'm sitting down, he'll jump in my lap and get right in my face with his complaining until I end up laughing and stop.
For a while, this only happened when I was home alone, (probably because that's the time when I am most likely to sing out loud) and no one believed me when I told them what was happening. This morning when I started to sing, the cat did something unusual. After voicing a few complaints, he redirected his aggression toward our younger cat and attacked her! I couldn't believe he was really that bothered by my singing! So I walked into the other room, humming along and he jumps out of nowhere and attacks my leg, literally clinging/hugging onto it like a leech! When I sat down, he got in my lap and acted agitated with me when I continued to sing, curious as to what his reaction to be. At this point, I was just perplexed and wondering if it was the pitch, the frequency, the vibration, or the loudness that bothers him most. It didn't seem to matter. If I sing or even hum, no matter how loudly, he freaks out. Well, evidently, he had enough of my antics and lunged at my face and bit me in the cheek! I threw him down from my lap and he then attacked the younger cat again! And again!
Later on, when Mike came home I explained to him what the cat had done. He still didn't believe that the cat could behave this way just because I sing, so I showed him. I broke out in a fairly rusty and unrehearsed version of Ave Maria and right on cue the cat started going nuts, with repeat performances of him attacking the other cat and trying to bite my face off! Twice in one day!
The odd thing is that tonight he became more and more aggressive toward the other cat the longer I sang. I did some research about this online and some experts say that a cat will become aggressive and redirect their aggressiveness to the lowest member on the totem pole, especially if it is scared or startled. It's decidedly so. My singing makes kitty scared. I'll stop now. I would hate to get bit in the face again.