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Rob,
Just want to be as honest as possible ^_^ so, here we go...
You need your voice to be deeper and more sticky and sultry like honey

In addition, I didn't notice this with you specifically, but in case you are wondering, I think it is better for one's voice to not be "hopping around", but staying at a relatively constant frequency.
I felt like you talking in your deep voice was like you were trying rather than it being natural.
By listening to the first recording, "Sexy Opener", I think I know where you are stimulating the muscles specifically. You need to go about a half inch to an inch lower on the vibrations. Does that make sense?
A trick I use to figure out how deep my voice can go is to make many long, deep, and loud sighs or yawns. Make the deepest, loudest, and longest yawn you can make and really say the word yawn. When you sigh, say the word sigh. And really try and make it resonant and deep. I'd do that and I'd make sure to pay attention where exactly is that "Sweet spot" for when my voice sounds really deep and masculine. I'd do it again and again and everytime I'd make a note of where the sweet spot is and when I was sure where it was, I'd try to speak and adjust my throat muscles so that they'd be incorporating the "Sweet spot" muscles that cause my voice to sounds very deep, sexy, slow, sultry. I realized that a huge part of developing that desired voice is relaxing the throat. Hum so that you focus the vibrations at the top of your throat, then gradually lower it down, down, down, like you are dropping something to the bottom of some well, or ocean, or pit. I've also found it interesting how pausing a lot for that dramatic effect just allows you to breathe in air to start up again. If i continue to talk in in the same breathe for too long, my voice will gradually get higher because my body is making due with the resources it has. Sort of like playing any wind instrument. You gotta make sure there is a constant stream of air and that the mouth is at a specific configuration to achieve a certain note you wish to play (assuming one's fingers are on the keys/buttons).
In addition, you need to use that voice not only in pickup but everywhere. I use that voice with my teachers, friends, strangers, idc because I want my voice to sound a certain way and if people are thinking something else when I'm not interested, too bad I'd think to them. At first it feels awkward, unnatural and forced. But over time you just do it automatically. I'm still fixing mine just cos I don't know if I am consistently sounding that way, but I'm becoming more and more aware of what my voice has to sound like
I grabbed some recordings I've made myself over time, made a soundcloud account and posted them up.
Click here for the link.
Take note of how my voice changes if you play them according to the dates in the title. It amazes me how much I've changed. But my voice isn't perfect so please criticize me as well! I love feedback
Hope this helps,
- The Wise Fool