The following response curves were taken in March, 2005 in a large Gymnasium.   The boxes were put on the floor of a basketball court.   The data is very good.   We can't claim the data is perfect, as the floor was not infinitely rigid, but these measurements were done with great care and with laboratory grade instruments.

Figure 1 (below) shows the response data for an Acoupower -01 15" driver in a small (2.6 Cu.  Ft.  Net) sealed box.   This is a 2.83V @ 1m half space measurement.   Even in a half space environment, this small sealed box is very flat, with a -3B point of 36Hz.   In a typical room this box has a small bump centered at 45Hz, a -3dB point of 29 Hz, and is still only -8dB at 20Hz.   Without EQ, the sound is terrific.   Exhaustive auditioning of this box by critical listeners has produced the following feedback: "The peak is low enough in level and in frequency, to give the bass a very slight 'low punch' sound with lots of authority." Also, "There was no audible distortion, regardless of drive level, the only extraneous noises were a result of the room itself vibrating.   I have never experienced that level of bass without distortion with just a single 15" driver, maybe 2, but certainly never with just one." Note that the in room SPL level will be a good bit higher, with up to +12dB possible with corner placement.   Given the incredibly high power handling and excursion available, a small box like this makes a great high output small subwoofer for limited space pro-audio applications.   Perfect for smaller dance clubs and live music venues.   For high end home theaters, high end installed systems, and high end home audio subwoofers, just a bit of EQ enables high output, audiophile responses to 20Hz.

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