acmebass
Commercial User
I don't think I've ever heard strong 30Hz
Um...yeah, I gather. It doesn't sound like you want to, either.
Dude- there are tons of hi-fi speakers which will easily reproduce a strong 30 Hz, some which will go another octave below that, into the infrasonic.
I use a Carver True Subwoofer which is strong to about 18 Hz.
I am intimately familiar with a handful of models for bass guitar that effortlessly reproduce 30 Hz, as well, and I know a few thousand other people who are, also.
This ain't the holy grail. I'm sort of getting the impression that you're somewhat invested in denying that such a thing is possible. Trust me- it's not.
Oh- and as long as we're down under, check out this Aussie subwoofer, flat to 16 Hz: http://acmebass.com/archive_files/mag_articles/audio_magazine/whise_320_subwoofer_09-1999.pdf
This company seems to have disappeared. I suspect that they heard from the Bose team of lawyers, who are known to be fairly aggressive. The impedance curve of this Whise, and that of the Bose AM5 are remarkably similar, and the qualitative description of how the Whise works suggest other similarities, as well.
Thanks,
Andy