Hertz Meter Reading Device

What you're looking for is called a 'Real Time' or 'Audio Spectrum' Analyzer(http://en.wikipedia.org/wiki/Real_Time_Analyzer) You can get software for a computer now that will enable you to analyze the SPL output of your speakers, in your room, at all(what are considered) audible frequencies:(http://www.trueaudio.com/rta_faq1.htm) Another very affordable method is the 1/6th octave RTA that the Behringer DEQ2496 provides(http://pro-audio.musiciansfriend.com/product/Behringer-DEQ2496-http://cgi.ebay.com/B-K-SINE-SQUARE-WAVE-GENERATOR-MODEL-E-310B_W0QQitemZ130323305278QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item1e57dfd33e&_trksid=p3286.m20.l1116UltraCurve-Pro-Mastering-Processor?sku=182484) The low freq cutoff for most RTAs is 20hz though. A greater problem of getting accurate measurements at the lower freq is the response(below 100hz) of most "calibrated" microphones. Mics that are actually accurate at the freqs you are interested in are expensive, and the testing device you are using has to accept the correction curve data of the mic. ie:(http://www.earthworksaudio.com/27.html) (http://www.linearx.com/files/pdf/M51_Mic_Brochure.pdf) To test for output at 11hz; you'd probably need a signal(sinewave) generator like this(http://cgi.ebay.com/HEATHKIT-AUDIO-GENERATOR-MODEL-G-2-SINE-AND-SQUARE-WAVE_W0QQitemZ160355544791QQcmdZViewItemQQptZBI_Signal_Sources?hash=item2555ef6ed7&_trksid=p3286.c0.m14) or this (http://cgi.ebay.com/B-K-SINE-SQUARE-WAVE-GENERATOR-MODEL-E-310B_W0QQitemZ130323305278QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item1e57dfd33e&_trksid=p3286.m20.l1116), an SPL meter(which again will have a mic that's inaccurate at low freqs) and a volt meter so you can be certain you are remaining consistant in your signal between your reference freq and the freqs for which you are testing. Hook the generator up to one of your preamp's inputs(with the voltmeter across the +/- outputs for calibration) and test away. There are many signal generators(more expensive) that have built in voltmeters BTW. The low freq cut off for Redbook CDs is 20hz, and there's VERY little on vinyl, outside of some direct-to-disc pipe organ music that even goes down to 16hz. You won't hear anything at those sub-bass freqs, but the visceral effects are fun.

Fab4- The IEC standards on Redbook CDs included the frequency response of 20-20kHz. Read under, 'Technical Details' on this site(click on 'Red Book Audio CD Standard', bottom of page): (http://tripatlas.com/Red_Book) Like most other things in this hobby; nothing is set in stone, and while most Redbook music CDs are recorded with the freq below 20Hz filtered out, there are some out there engineered with info below that(mostly test/tech CDs). Note what are cited here as the lower freq response limits of CD and SACD: (http://www.answers.com/topic/super-audio-compact-disc), under 'Overview'.

I REALLY should have chosen my words more carefully there. Happy listening!!