Besides positioning you speakres correctly is one thing but If you did nothing regarding your room acoustics you can try Mathaudio Room EQ ( mathaudio.com ) in combination with Foobar2000 completely for free. But first invest in a decent measuring mic like an UMIK-1. Did spend quite some money on audio gear in the past where you can buy a nice car for. The lousy 90,- euro’s for a measuring mic was the best audio investment i ever did (i’m 61 now). It leveled out my frequency response
drastically whit an outstanding result for instance in imaging.
Here under my frequency respons graph. You can see at some point there is a almost 15 db gap this is killing my lows. mathaudio corrected this flat (my target curve that i can draw my self in mathaudio room eq an i prefer). Measuring is KNOWING let your ears do the rest.