The low E-string on a bass guitar is usually tuned to 41.2 Hz, while the lowest note on a standard piano is A at 27.5 Hz. The harmonics are all multiples. Anything less than 27Hz except for a Gravitone - a resultant 64' flue (a 32' stop combined with a 21+2⁄3' stop, which is a fifth, producing a difference tone of 8 Hz on low C.). That's the basement.
Bass- at what frequency does it change from sounding like a string to just a low tone?
I have two subs and speakers I like. I have little experience comparing them to anything else. As the frequency of a given note goes lower, at some point in my system it stops sounding like an instrument making the sound and instead it just sounds like the sound. I’m not crazy about this, but maybe that’s how it is for everyone?