This looks more like a "tactile transducer" from the graph, more sounds you feel versus hear. Below the audible range of hearing, I doubt the non-ruler flat response would matter all that much.

Looks interesting but someone asked the question before, "Does 5 Hz really qualify as a sound?".

Or is it more of a ticking, or thumping? My wall clock is rated down (and up) to 1 Hz!!!

-Dave

M80s VP150 QS8s EP500s
ravenmanor.com/cinema/