Mac Pro's external noise isolation

I need to record vocal mono on the same desk as my 3,1 MP for screencasts. I'm considering an mxl 990 condensor mic as I've read it does a decent job at isolating most external noise. But my internal hard drives and MP fan have that constant idle noise hum. I realize I'll still have to do post noise cancelation filtering for each session.

Is there a better condenser USB mic for about the same ~$100 price point that can better isolate the vocal?

I'm trying not to use my Mac Book for the audio recording as my MP records the screencast at a much smoother frame rate for things like zoom in/out.

 

Wise words, but I need to be there with the MP for the video part of the screen cast so that no frames are dropped. If I could run cables from my basement to my office I would.

Will look into the Shure's

 

It's interesting that you recommend a dynamic instead of a condenser. My understanding is that the USB condensers, even though preamp is built-in and low power, is better for freq. range and warmer and less muddy. I always see podcasters using condensers.

Will I lose that voice quality for better sound isolation using the dynamic sm57?

 

Cables for DVI, power, USB, Firewire... I'd spend more on cabling than the mic itself.

I may just end up tying to dampen the MP under the desk.

Would the sm57 need a guard as well? Is it poppy?

 

Good tip, now I just need a mic to put behind it

I'm still leaning towards a condensor mic as I think a dynamic seems to work more for live (and loud) performances.

 

Great vocals, but you're leaving out a piece of the puzzle: the $1K preamp that's hooked up to the shure m57?