FIR Equalizer & Timbre Matching

[kareface]

So I was having a conversation with a friend of mine about timbre matching. He seemed to believe that equalization could correct for tonality. While it can help, it can't fix speakers with poor matching. He brought up the use of a fir equalizer. I said it still wouldn't be enough, but I was curious what other people thought about the matter. It's really a 2 part question, would a fir equalizer be capable of correcting the difference in tonality between 2 speakers with very different tonal qualities, and would it also be possible to us it to correct ones that were similar, but audibly different prior to equalization?