Making speakers sound tonally similar with an equalizer

Short answer, no.

You can’t easily improve dynamics, dispersion or bandwidth via equalisation. Not without introducing additional distortion artefacts.

However you could make their frequency responses sound a lot closer.

In fact quite a few people already do this with headphones.

They simply dial in their saved preferred equalisation via the method of choice for every headphone they use. I tend to use some equalisation for every headphone I use. It’s not always easy as what can sound like an improvement with certain music/recordings can sound like distortion with other types.

@asctim 

I would bet though that if you took two different reasonably well designed speakers with the same baffle shape, same driver sizes and driver placements on the baffles, let’s say a 5" woofer and 1" dome tweeter on 16" x 7" baffle, they could be equalized and phase corrected to sound similar enough under blind testing that most typical listeners and even a lot of seasoned audiophiles would have a hard time distinguishing them.

I guess you could say the same about a lot of speakers put to a blind listening test.

Anyway, I don't think anyone is actually suggesting you can make 2 different speakers sound the same, only more similar in frequency response.

Whatever else, tonal balance is still a pretty important part of a speaker's sound, and it's good to know that adjustments can be made.

You might say that a flat pair of speakers in a flat room doesn't need tonal correction, but not everyone has that luxury.

I can recall an enthusiastic review for the diminutive Harbeth P3 where the reviewer felt it sounded remarkably similar to the vastly larger M40, just missing the (all important?) bottom octave.