My lighting arrangement is fully explained in the
blog entry.There are some major differences between the way I did it an the way that you've done it.
Firstly, my product base was a piece of 'black glass', a smoked glass table top, this produced a reflection of the subject, and apart from the difference in the visual effect, following the principle that the angle of reflectance equals the angle of incidence, the light from the overhead softbox bounced off of the glass at the same angle as the angle at which it struck, which means that it didn't light it.
Secondly, my camera height was much, much lower. You're looking down from above, which has created perspective distortion and also an out of focus area. But it has affected the amount of light visible on your product base too, because it's showing much more of it, due to the higher camera angle.
So, your background isn't really a background at all, it's a product base. My background is a white wall behind the subject, it doesn't show as white because no light is reaching it. This allows for the background to be lit separately (if required) as in this shot
Where a blue gel over a second light has added the background light.
The shutter speed isn't relevant. All that you need to do is to make sure that no light reaches the background (which isn't possible when the background is in fact the product base) or to use a background/product base that either reflects almost no light at all (black velvet) or which reflects a lot of light (glass) but which reflects the light away from the lens.
That isn't relevant either, what matters is the ratio of light (the amount of unwanted light that reaches somewhere it shouldn't) not the quantity of light. This is fixed and isn't related to the power setting of the light.
