for frequencies:
       250       500      1000      2000

1a. two sources have equal and in phase pressure signals:
radiated net power (W):
  291.1987  174.8645  185.1136  185.0266

power level (dB):
   94.1793   92.9479   93.0716   93.0705

sound pressure (Pa):
    0.0288    0.0250    0.0254    0.0254

pressure level (dB):
   63.1793   61.9479   62.0716   62.0705

1b. two sources have equal and 180 degree out of phase pressure signals:
radiated net power (W):
   68.8013  185.1355  174.8864  174.9734

power level (dB):
   91.4058   93.0718   92.9482   92.9492

sound pressure (Pa):
    0.0210    0.0254    0.0250    0.0250

pressure level (dB):
   60.4058   62.0718   61.9482   61.9492