The subwoofers are solidly built, frequency response goes down flat well below audibility.

Need at least a stable apmplifier of 200 watts continuous power. All items added up will be very costly.

These subs can reproduce awsome bass down to 8Hz! Yes, 8Hz. But it must be used with the ELF-1 electronic unit or all bets are off. The ELF-1, which is an incredibly elaborate and versatile pro unit with balanced inputs/outputs and lots of settings and adjustments. A single unit can drive any number of amp/subwoofer hookups. Different subwoofers, regardless of size, all have the same response characteristics, differing only in efficiency and maximum SPL capability. The sound of these subs are more solid, clearer, more details, less rumbly and more revealing than any other subwoofers.