The ZV28 Profundo Powered Subwoofer can deliver bass so low as to be at the very limits of human hearing. The advantage of this capability, even if you rarely need it, is that frequencies that stress lesser subwoofers are reproduced effortlessly and powerfully by the ZV28. The ZV28 Profundo Sub is a self-powered, self-processing, self-protecting, vented, direct radiating subwoofer with a large internal volume and a very low tuned frequency. Anti standing wave baffles and pass-through dampers minimize upper resonances while very large ports maximize low frequency performance at high output. Protection systems and limiters control all manners of overload, including thermal, excursion and clipping. The ZV28 is optimized for full-power operation. It is designed to operate at full rated RMS power throughout its operating range while ensuring the woofers remain within their excursion and thermal limits. The ZV28 delivers consistently flat frequency response from 1 watt to 3000 watts. A pair delivers response that is -3dB at 21 Hz. No equalization is required to achieve this response. The response is available at high levels in real-world applications. Thanks to the low-bass sensitivity and the robust components, massive low end is delivered when the prodigious power is applied. The ZV28’s sensitivity is achieved, and maintained, though careful optimization, the use of premium components and innovative, proprietary thermal management techniques. The ZV28 is not a paper tiger. It delivers what it promises. Other subwoofers can be made to look similar on paper, but come up short in the field. Beware of loudspeaker systems that require processing to achieve their claimed frequency response! Those systems are still subject to the excursion and thermal limits of their drivers. Boosting low frequency EQ to achieve extended low-frequency response on specification charts isn’t the way to deliver superior results at maximum power. In fact, boosting low frequency EQ is likely to result in excessive distortion or woofer damage at full power. Under those circumstances the system cannot be utilized at full power. If limiting is applied to avert such failure, that limiting prevents the realization of the claimed frequency response at full power. The ZV28 does NOT have low-frequency EQ boost and does NOT suffer from these limitations. It faithfully delivers extremely low bass, very loudly, where most others either roll off or die trying.