You read the spec sheets of your new speaker. Flat to 17Hz! Brilliant. You wonder how an 8" driver with a port can do something like that, but then, engineers are magicians. You fire the system up and there's no low bass. The pipe organ rattles nothing, the notes of keyboards and acoustic bass do not reproduce their lowest. What's going on? Have you been lied to?
Yes and no. You've been given an academically correct answer. Your new speaker can do what it's advertised to do, but not in your room and certainly not where you're sitting.
There are a couple of things going on. First, while an 8", or any smallish woofer, can go down low, it hasn't enough surface area to effectively couple with the air in your room. Which means that if you sit very close to your speaker you can hear some low bass. Academically correct, functionally incorrect. And what of the small two-ways we hear at shows that have us looking for the hidden subwoofer? Well, they aren't going low either, but they've cleverly tuned the system to be flat at the lowest note's second harmonic (double the frequency of the actual note) and your brain fills in the missing low notes. A clever magician's trick, but nothing that will move a pant leg.
There are means around this. If the smallish woofer had been powered, we could use brute force to compensate. Or, if the woofer had been bigger–say, a 12" or even a 15"–the coupling would have been better. Or, had we (even) a smallish subwoofer, we could place it in a part of our room that supported low bass–which is almost never where your speakers sound best–and got something of value there as well.
We work hard at ensuring our electronics are flat to below 1Hz. It's a shame few get to appreciate what fine low frequencies they are producing.
