Free air, tighter bass - snake oil or cheap tweaks?

Your observation is correct, and it does seem counterintuitive. The speed of sound generally increases in less dense media, such as humid air compared to dry air. However, the perception of sound can be affected by various factors.

In the case of humidity, it might not necessarily cause the sound to be muffled directly. Instead, humidity can affect the absorption and dispersion of sound waves. High humidity can absorb some higher frequency components of sound, leading to a perception of muffled or dull sound.

Changes in weather conditions, temperature, and humidity can have complex effects on how sound behaves. While the speed of sound may be faster in humid air, other acoustic properties and environmental factors can contribute to the overall perception of sound. It's an interesting phenomenon, and your observation during the rainy season may provide additional insights into these acoustic effects.

@yesiam_a_pirate +1 “Dreaming about and working towards the "next thing" is sometimes more fun than the score.”

Banking back to being serious.....and perhaps an interesting query, @erik_squires 

What if I’ve an omni on a column, with nothing that could be considered a side?

All I could do is wrap the column itself...and have been considering a tapered column that would ’accentuate’ the taper of the Walsh drivers....

On a practical level, too top-heavy imho....

@classic8 ...no kidding...*L*

....we can ignore the room for the moment....That becomes a whole discussion of and by itself....

Apply the KISS option... ;)

@asvjerry  If it's something like a Walsh speaker, the bass section provides plenty of area to cover, for an MBL though not so much.