Bass: how low can you go?

It was Rock Night last night. Thanks to those who came and to those who made it happen! I was looking at the bass bins. Speaker cones are meant to spread out the sound waves in all directions by diffraction. In other words, it would be bad if you could only hear the sound if you were stood directly in front of that speaker cone. What if you were slightly off to one side? Diffraction takes sound waves and makes them into semi-circular wavefronts going in all directions. But it works best if the size of the hole is the same as the wavelength. Take the stop speaker. Diameter is roughly 30cm. For waves, speed = wavelength x frequency. The speed of sound is roughly 330 m/s. If the wavelength is 0.3m, then frequency = 1100 Hz. I've never done the calculation before. That's a surprisingly high frequency for bass. The slightly smaller cones below will work best for even higher frequencies. So if you want to hear the very lowest frequencies best, you'd probably need to stand more or less in line with the speaker.