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I agree that the lowest octave adds a ton of drama and emotion and is valuable to a music lover. Humans are programmed genetically to fear loud and low noises, so ultra-LF content triggers our reptile brain to squirt adrenaline. Composers know this and put the musical thunder in there deliberately. Prokofiev is an awesome composer for symphonic bass drum. Check this particular recording of
Lt. Kije Suite, a film soundtrack he wrote in the 20s. People love their hotrods and Harleys, airshows, Niagara Falls and sonic booms for the incomparable thrill of the sound. U2's huge concert sound was from the bassist's foot operated synth bass doubling under his fender bass the root notes in the chorus. Awesome!
If the bass rolls off too high like in mid-bass then you get phase shift with the rolloff. This phase distortion, or group delay is said to be the cause of the infamous "slow bass." All bass is slow of course, but time misalignment with the midrange where the speed information happens makes bass sound separate from the music and slow. The lower and flatter the bass extends, the lower the phase shift happens, so ideally, with flat extension to 20Hz or below, the rolloff and the phase distortion happen below the "audible" range and you don't have the dreaded slow bass.
But to reach 20Hz and still have some grip on the air to make musical texture and not just sine waves you need excellent acoustic impedance to the surrounding air. Which means several very large diaphragms with large excursion, or an air to air transducer, like reflex port or organ pipe. The smaller the bass driver cone, the worse the impedance to the air, the more sloppy the grip, the softer the SPL and the more the sound is like a sine wave, no texture at all and no excitement. You need largest area diaphragm possible to get the ultra LF texture and detail. The larger the better because these LF wavelengths are 50 feet long, played by a 1.5 foot cone. Compare that to a tweeter playing a 1.5" wavelength at 10kHz with a 1" diaphragm, it takes only a couple watts to play just as loud as the bass driver using 1000W at 20hz. We love the tweeter detail, we love the bass detail, but that's a bit harder and more expensive to pull off.
And there is plenty of detail down there. Fender bass makes mostly sine waves, so small drivers don't hurt too bad playing classic rock, but synths and acoustic instruments make far more texture. Square wave bass is what the kids really want -
the sound of alien laser guns blowing up planets. For instance I have a recording of Tchaikovsky 1812 Overture. It has full size military artillery cannons shooting outside. You can hear the reflections of the booms bouncing off nearby hills or buildings and there is all kind of other reflection information in that .5 second delay. It was all audible on my old Legacy Focus 2020 speakers with 3 12" woofers and two 2" reflex ports per side. No other speaker I've had since then could match it. I connected NuForce amps directly to the speakers and play the full 2V line signal into them with no attenuation. I stood 40 feet away in the kitchen cooking dinner, but that incredible bass would have me falling on the floor overcome with emotion. Yes, it's worth it, and it's musical, not just a audiophile trick.
The audible range is not the limit of perception. We can feel the vibrations below what we can hear with ears. If the transducer has sufficient acoustic impedance to affect the surrounding air then you can feel the subsonic vibration in the air.
You can hear texture and detail in LF sound just like you can hear it in thunderclap made by a 2 mile long "line array" lightning bolt. No driver cone has big enough area to do that, so it must be created by an air to air transducer, like an organ pipe or reflex port, or lightning bolt.