Subwoofer question - and Human Hearing

[algernon]

Hello, I was playing with a tone generator to see how low my system can go, and I noticed something weird. Perhaps someone can explain it.
It is a M&K with 2 8" drivers in a push pull configutation. If I go down in frequency, it seems to be pretty flat until just before 30 Hz, where there is almost nothing. But if I continue to go lower, the level comes up again, and I can hear something down to about 12 Hz where it dies again. Now I know it is very unlikely that this sub is going that low, or that I could even hear less than 20 Hz if it was, so is it resonance, driver noise or something else that I am hearing? The odd thing is it does sound lower in pitch then 30 Hz and up. I am using a PC based sine wave generator for the tones.

Weird.

 

[MDS]

I would say the sub is trying to reproduce the 12 Hz tone that it cannot handle and is producing harmonics of that tone at 24 Hz, 36 Hz, etc which can be heard.

 

[j_garcia]

That's what I would say too. It doesn't mean the sub is actually playing a 12Hz tone, it is an artifact of the sub trying to reproduce that tone.