As for DSP in subwoofers, it is used for two things and it is important to distinguish them.
1 As a means to shape the frequency response (boost the lowest frequencies), and as a way to manage the demands put on amplifier and drive unit. Mostly, this is done by reducing the deepest bass output at higher volume, to limit distortion and potential damage to the driver. DSP can also be used as a more refined digital crossover.
2 To measure and then correct in-room response. For this, the system has to measure in-room response with a test tone sweep and a calibrated microphone, construct a correction curve, and then apply that curve.
These days, many subwoofers do 1) and some also 2), such as the bigger models by Velodyne and B&W, but rarely as well as the Antimode 8033.
1 As a means to shape the frequency response (boost the lowest frequencies), and as a way to manage the demands put on amplifier and drive unit. Mostly, this is done by reducing the deepest bass output at higher volume, to limit distortion and potential damage to the driver. DSP can also be used as a more refined digital crossover.
2 To measure and then correct in-room response. For this, the system has to measure in-room response with a test tone sweep and a calibrated microphone, construct a correction curve, and then apply that curve.
These days, many subwoofers do 1) and some also 2), such as the bigger models by Velodyne and B&W, but rarely as well as the Antimode 8033.