May be a dumb question...

[menglind]

I'm pretty much a noob at recording, so I may ask some really stupid questions. I can only ask for patience while I learn.
My question today is this; Is there a tool, software or hardware, that will allow me to lower the level of the instrument tracks when the vocals are present, and bring the instrument tracks back up when the vocals are silent? I have tried it with automation and my computer mouse, but there is no real control over the movement. I don't have the luxury of an an external mixer/controller with faders that will interface with Pro Tools. I simply can't afford to spend thousands of dollars for that.

Is there a better way to accomplish this? A friend suggested that I just make the snare and vocal tracks louder than the guitars, bass, etc. I can do that, but I don't like the way that sounds on a lot of the songs I'm mixing.
Thank you for any response.
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Dell Studio XPS Model 8300
Intel i5 16 gigs of RAM
Windows 7 64 bit
M-Audio ProFire 2626
Pro Tools 9 MP