[bobgpsr]

That must be some type of in-room spec (a small monitor room?). A more accurate and consistent way of comparing subwoofer frequency response is in "tests outdoors on a big field with no nearby large reflective surfaces (usually ~10 m distance is considered adequate for testing frequencies down to 10 Hz). " if an anechoic chamber rated for very low bass freqs is not available. See Subwoofer Tests Explained for testing methodology.