Lots of people do equalization, but mostly just by ear. Tools to use SCIENCE to do it are now cheaply available.
1) play music out of your computer with an equalizer. I use Foobar2000. There is a free 31-band stereo equalizer plug in available for it. http://www.foobar2000.org/comp...
2) play some Pink Noise through it. Pink Noise is equal energy per octave, so on a log frequency graph of SPL it should be flat. Of course, it won't be b/c speakers and rooms are imperfect, but now you have a goal. Download a pink noise sample, or make one with something like Audacity. Probably use a non-lossy file format.
3) get a smartphone app with a Real Time Equalizer. iphones have consistent mic performance, so the software can usually correct for it well, but I have had some bits of software behave oddly. I paid a few bucks for this one ( http://www.studiosixdigital.co... ) I understand there are android apps also. You can buy a measurement mic for your phone cheaply ( http://www.parts-express.com/d... ) if you want.
4) The RTA will measure your SPL vs Frequency, and your pink noise sample is sound that should have flat response. So use your equalizer software to twiddle the sliders until things are flat. Microphone location makes a difference!
So if you have a smartphone and a computer this can be done for somewhere between free and $50. Some people are good at equalizing by ear, but bringing some tech to the table will help most people get better results.