What is the most dramatic way of increasing a speaker's Bass and Low mid?

The more i listen the more i realize that there is a specific volume and sweet spot of sitting where they sound just unbelievable, above that volume they begin to sound harsh to my ears. Same for leaving the sweet spot.

Also they just want to play great full sounding recordings, they make any recording that is not stellar seem naked and harsh... Listening to the last Bootsy Collins this past hour. WOW, sounds amazing! earlier Steely Dan sounded terrible and thin (go figure).. i guess you need music that respects bass on these...;)

Also classical sounds really good on these. Pop and rock for the most part sounds harsh.
What im thinking is that these speakers are probably so pure that all the added high end that is associated with pop/rock studio production is very unnatural and unrealistic(I know because i mix for a living...) just don't translate well on the Merlins, while Classical and Jazz and Funk which is really amazing players recorded really well and generating a very balanced frequency range translate great.

This is where these speakers shine. They are not for originally thin recordings, they just don’t "help" them as other speakers do. And thats a good thing and a bad thing...

Point is- i come from music, not form love of sound reinforcement necessarily, so i cant choose music for my speakers, i must choose speakers for my music. Its not like im going to listen to music that my speakers like. That would be quite sick. Half my library does not translate well at this time... And i plan on listening to my library.,

So we’ll see, because im in love with them on music that sounds good on them.
Might have to insert a good EQ probably and adjust by record... just like i do when i mix at the studio...

Thanks

Dear @dumbeat: "  And thats a good thing and a bad thing. "    "  Half my library does not translate well at this time. "

I know and listened your Merlin speakers.

First time I heard the Dynaudio Esotar twetters was many years ago ( today Esotar 2 but from some years now Dynaudio is not any more a driver suplier for any one but its speakers. ) through a Sonus Faber monitor that till today was the deepest dimension of any two way speakers I never seen ( can't remember the model. ) and the hf range was to brigth/hars. This kind of characteristic I never listened in the own Dynaudio speakers designs maybe because they know exactly how to handle it. Esotar 2 is a little better but still brigth.

There is no reason for you can continue with that kind of quality level performance and if I was you what I will do is to change the Merlin's for something you already know very well ATC ones.

Merlin has that trouble no matter what. You need to change its design to achieve top level and maybe you can't get it.

ATC is one option about.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

@rauliruegas 
there is something about them that i really love very much. I will play around with my other components and room a bit more before changing them.