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

Dear @dumbeat: There is no perfect speakers or audio systems, nothing is in audio.

Maybe speakers is the more critical and delicated ling in audio system chain because it is not only from where the sound comes on but because its direct relationship with all the links in the overall audio system chain including room and each one of us music/sound priorities.

In those order of premises what for you is rigth maybe for me or other gentleman it's not.

I don't like two-way speakers because to many " compromises " but for other people are the Nirvana.

Yes, you have to make your home-work about and I hope with the success you are asking for.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

dumbeat@
 You can try use different cable ,  move you speakers back ,  but you 
never get not only dramatic changes , may be very very small changes.
you can listen my advise or not , but as speaker designer i suggest you 
first-most easy way , use  equalizer to boost 100-400 Hz, second more
kosher way, use you sub and change crossover in you loudspeakers
 apply baffle step crossover and high pass crossover for you 6.5 woofer.
http://diyaudioprojects.com/Technical/Baffle-Step-Correction-Circuit-Calculator/    and third , most efficiency dramatic way--- get 3 way good
Loudspeakers with 500 -700 Crossover frequency between woofer and midrange  

How did the Loki do for you?

+1, about Loki performance???

Get four subs and use Room EQ Wizard (free) but extremely powerful, put those measurements into Multi-Sub Optimizer (free) amazing you can see the graph improving as the program creates filters, which crunches the numbers and builds the filters I put into a Mini DSP. You can do up to 12 couplex biquad filters. . . It’s amazing the impact, accuracy, and power that the subs have when they work together.