I perform a song live where I have to almost whisper one part, even though the music is still playing quite loudly around me, and I'm having real trouble making myself heard at this point.
 
Is there any kind of boost pedal that I could use to momentarily increase my volume by a few dB?

Can't you just whisper louder?

Sorry, don't know about the pedals, I assume there are such, but isn't there a big risk of feedback loop?

Aren't there volume pedals for guitars? Could such work for you?

turn up the gain and you risk feedback. 

When I played live, we normally ran the vocal mics up as far as we could go before feedback occurred. Set the EQ and make minor adjustments and let it roll from there. 

I don't know of any magic bullets that will get your vocal any louder on a live stage without exceeding the feedback threshold.  The best option would be to have the other players play softer if the goal is hearing the whisper vocals...... it will add some cool dynamic to the song. Or, have just one thing play like a muted guitar part.... be creative. 

"The best option would be to have the other players play softer if the goal is hearing the whisper vocals...... it will add some cool dynamic to the song. Or, have just one thing play like a muted guitar part.... be creative." Not really an option when you're trying to do a faithful cover of a Slipknot song!!

Slipknot probably has an automated volume level controller on the vocals that is already synched to the faithful backing tracks the band plays sync to.



best regards,
mike

you can do things in a studio that you can not do on stage as easily.  I wonder how the slipknot did it on stage.....? 

For live performances when getting into that quiet whisper type range try "cupping" the mic in your hands or at least sliding the hand you are holding the mic with up around the top of it (choke up on it so-to-speak). This causes more of the upper frequencies to bounce off your hand and back into the mic giving you more high end presence. I use this trick while performing Bodies from Drowning Pool. check out the video here: http://www.youtube.com/wa...K7j2xqxGE&feature=plcp

This is what I use, it works quite well.

I think I missed your point. If there was one?