Interesting observation. Comparing cabinet weight to dB production... Values were taken from each manufacturers web sites and -3dB was deducted from the Peak listing. Less than 4 dB separates the four cabinets for continious output. Model - - dB per pound SP 18a . . 1.12 SbA760. . 1.30 SWA1501 1.40 KX 12. . . 1.76 This is an 18" followed by two 15" followed by a 12"