Testing Bass Extension on Speakers

I have Stereophile's Test CD One. On this CD they have warble tones at different Hz. 1kHz, 200Hz, 160, 125, 100, 80, 63, 50, 40, 31.5, 25 and 20Hz. There has been discussion about the low bass in speakers. Am I right in that if your speakers cannot reproduce any of the levels, this would give you an idea of how low they will go? I set my system listening level to a level lower than what I would play if sitting and listening, but not to low. My speaker reproduced all the way to the 25Hz, when it went to 20Hz I couldn't hear it. I cranked up the volume and could faintly hear it but I was way into the amp.
Go to Radio shack and buy a sound level meter 35.00 or so. Then you can tell how many dbs the speaker is up or down at any Hz. using the meter and test CD.. This meter is very useful in speaker set up and this kind of testing, as you can tell where the various peaks and dips in it response are.. J. O.
I frequently use the very same stereiphile test disk to test speaker frequency response whenever I re-locate my speakers and/or subwoofer in my listening room. It's usually not a question of whether or not your speakers will reproduce the frequencies below 30 hz, but at what level in comparison to the rest of the frequency range? Most full range speakers will begin to have less output below 30hz. So the next time that you conduct this test, compare the low bass output level to that of the frequencies above 30 or 40 hz. You will probably have to conduct this test at a fairly high level to get a good feel for the level differences, unless you have a spl meter. This will give you a better feel for your speaker's low bass capabilities. Happy listening!
If your system SPLs are flat down to 25hz that is excellent. Very few speakers (including Subs) and flat and undistorded down to 20hz. At 20hz you almost feel more than you hear. There is little musical content at 20hz, so unless you lisen to recordings of cathedral organs your speakers are fine.