I'm assuming this question is in reference to your prior post.
So...
You may want to consider a paramentric equalizer
like a Aphex 109, they typically run $200 or less used.
The Aphex website is
www.aphex.com
Another good sounding option for a home or project studio would be
either a Joe Meek VC5 equalizer (mono/stereo), or one of their various
"channel strips" that provide mic pre/compressor/EQ all in one unit.
They usually have a three band EQ, some with sweepable frequencies.
Their website is
www.joemeek.com
Typically the cure for "muggyness" or muddiness is twofold;
1) Keep the vocalist from being too close to the microphone and/or
2) Cut the offending frequencies via EQ.
Using a screen type pop filter in front of the microphone helps keep singers
from getting too close, in addition to avoicing "pops".
Hope this helps.
Chris