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

the speakers in case are VSM's but the question is general about Acoustics and coupling.

I have always run my mains full range and augmented the low freq with a sub.   I know a lot of people hate subs but if you set the crossover low you will avoid the boomy sound subs get a bad rap for .

I use a Velodyne SMS 1 as my lpw pass filter and experimented with the low pass crossover and slope .  The slope is very helpful in tuning the sub to blend seamlessly with the mains.  

A lot of new subs auto eq also which also helps eliminate the boom caused by the room mode...  

Spikes = better imaging and clarity, "tighter" bass, but not necessarily "more" bass.  Ime best to experiment with positioning BEFORE you install the spikes. 

@Dumbeat
Try one or more from the cable co or by used . You will be shocked .
I have sold my Dominus power cord and the XLR interconnects , but only because i needed the money . I will own them again .
To me they are my favorite cables that have ever tried .or owned .
They are that good IMO
They have awesome Bass and very good clarity and PRAT

I owned Merlins for several years. Bobby recommended setting the speakers 6 feet apart and then listen and widen them if needed. I ended up at 6.5 feet wide. I sat 7 feet, 3 inches from the tweeters. The speakers were 3.5 feet from the wall behind the speakers, and about 3 feet from the side walls. With this placement, I felt the sound was quite good, very coherent, with no problems with bass or midrange. This was in a small-ish room, 14 x 13.

I tried the speakers in my 20 x 18 living room that opens up into a similar sized dining room. If you can picture it, there are only 3 walls in my living room. The VSM’s did not sound good in this room, hard as I tried. The sound was quite thin.