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

I haven’t read though the entire thread but, try high quality room treatments. I highly recommend the Stillpoints Aperatures.

Still, in this day and age, most people would rather trade a component for another at a loss/on top of a big extra expense instead of taking the time to try room treatments. Some have mentioned trying a Lyngdorf. My feeling is to get as far as you can go passively.This is the best path.

I am having the same problem with my b&w 800d. Suspended wood floor with 13/32" subfloor of particalboard. Crappy. Need to decouple speaker from floor. Spikes will couple the speaker to the floor. Isoacoustics have  newer product - footer that  will help decouple. Like the nordost sort fut  or some stillpoints options. Also townsend seismic platform.

Hello,
          Your request is not possible with the speaker you have, period. I have PMC speakers which are transmission line design and have great bass at lower levels but to get an increase at 28hz is unrealistic. I use a PMC twenty5.sub for foundation level bass below 60 hz. It blends in perfectly. Don't waist your good money on tweaks. 
Happy listening.

dumbeat

My experience with 2 way speakers ( rear ported )  showed me that 
moving the speakers closer to the walls create bass bloat ,
so stay at least 2 feet from the front wall .
Spikes are good as others  have suggested , but the thing that
made the bass stand out the most was corner room treatment ,
for my room it was the corners behind the speakers that cleaned up ,
cleared up and tightened up bass response .
Cables do make a difference , try to find 10 gauge or larger .

Good Luck
Rob

Hi , I’ve had similar issues, but with a different type speaker . I am not able to buy a $4k item for tone , since I currently exist in a Mid-Fi price point . 3 kids with cars and college just ended , so maybe soon . So I purchased the Schiit Loki and have had good results . I’m currently running Zu’s on extremely thick carpet , but get decent Bass . So I tried different spikes and spent $400 on some really nice Timber Nation footers . Unfortunately they killed my sound ( I was really surprised ). I emailed Zu and Sean gave me some suggestions to try . In the end I removed the footers . But contact your speaker builder as they know the best tweaks for their products . I have tube amps and pre , so I was able to adjust my bass by running KT120’s over smaller power tubes . But it’s always give and take . For little or no money you could try digital correction programs on a laptop streaming Tidal . Amarro for example when used on a Mac , will do MQA unfolding and frequency curves prior to your DAC . You can trial it or buy for $100. So on the cheap , the Loki , footers, digital software. Hope this helps, Mike .