Response to 11 hz does NOT mean you have useful bass (not base) to 11 Hz. That number is probably down by 20 dB, practically inaudible relative to higher frequencies. Are there recordings that go below 20 Hz?
Most subwoofers start rolling off at 30 Hz or higher with a 24 dB per octave slope. By the time they get to 25 they could be down by 6 dB or more. They may also produce gross amounts of 2nd harmonic distortion. Taking the Fletcher-Munson hearing curve into account, we'll hear the harmonic more than the fundamental.
There may exist frequency meters, but as stated above, all you need is a test CD, an SPL meter, AND the response curve of the meter to correct your readings.
Most subwoofers start rolling off at 30 Hz or higher with a 24 dB per octave slope. By the time they get to 25 they could be down by 6 dB or more. They may also produce gross amounts of 2nd harmonic distortion. Taking the Fletcher-Munson hearing curve into account, we'll hear the harmonic more than the fundamental.
There may exist frequency meters, but as stated above, all you need is a test CD, an SPL meter, AND the response curve of the meter to correct your readings.