Equalizer in a Hi Fi system

Absolutely yes to using equalization for room correction but in this day and age DSP is the most powerful tool to do this best, not analog eq technology that was the best one could do practically say 10-20 years ago or so.
 

If you have a good quality system to start with, corrections for room acoustics is the missing link in most cases to reference quality sound and modern DSP tools provide a much more powerful, cost effective and flexible way to tackle room acoustics properly, though for the less technically inclined, a good old fashioned parametric equalizer could probably do the job.

To the best of my knowledge graphic equalizers with fixed ranges lack the flexibility to precisely do correct room corrections in most cases in that each room is different and graphic Equalizers lack the flexibility needed to do the job correctly.

There’s certainly a lot of good discussion about this earlier in the thread 

I have had a dbx Driverack 360 for about three years. It has a Wizard that will automatically sets your parametric eq at 14 different levels, sets your roll off points for them as well. Phase control for your mains and subs, a graphic eq, adjustable slopes for your roll off points, sub-harmonic synthesizer and on and on. It has a DAC I don’t use and am embarrassed to say until a few months ago, I didn’t use the auto wizard, but instead thought my ears could set it manually. You can set delays on your subs or mains. I love it. My son also bought a similar unit and loves his too. Don’t count this one out, until you try it. Besides my phono cables,  I use all XLR cables which plugs right into it. This may dissuade some of you. There are adapters made that convert RCA to XLR. 

You CAN do XLR to RCA in many cases with custom grounded cables like my Cardas. Obviates the need for undesirable extra box or converter. 

Mogami Gold XLR to RCA can be bought online and are already properly grounded to work without converter box for most matings of pro and consumer hi fi