http://www.earlevel.com/main/2010/12/20/biquad-calculator/

Lowshelf: Samplerate = 50kHz, Fc = 150

+10dB a0 = 1.0104259053944966 a1 = -1.972965178511578  a2 = 0.9636480378515397 b1 = -1.9733442497812992 b2 = 0.9736948719763152
+8dB  a0 = 1.0078253703887436 a1 = -1.9730791993116839 a2 = 0.9661345520571872 b1 = -1.9733442497812992 b2 = 0.9736948719763152
+6dB  a0 = 1.005513166727312  a1 = -1.9731697692525536 a2 = 0.9683561857777488 b1 = -1.9733442497812992 b2 = 0.9736948719763152
+4dB  a0 = 1.0034568021866632 a1 = -1.9732417115138037 a2 = 0.9703406080571474 b1 = -1.9733442497812992 b2 = 0.9736948719763152
+2dB  a0 = 1.0016275517798898 a1 = -1.9732988572831849 a2 = 0.9721127126945397 b1 = -1.9733442497812992 b2 = 0.9736948719763152
0dB   a0 = 1                  a1 = -1.9733442497812992 a2 = 0.9736948719763152 b1 = -1.9733442497812992 b2 = 0.9736948719763152
-2dB  a0 = 0.9983750928406495 a1 = -1.9701377485819662 a2 = 0.972112708207818  b1 = -1.9700924298424471 b2 = 0.9705331197879867
-4dB  a0 = 0.9965551061299993 a1 = -1.9665462882718263 a2 = 0.9703405964805928 b1 = -1.9664441032377802 b2 = 0.9669978876446386
-6dB  a0 = 0.9945170616260989 a1 = -1.9625245248692562 a2 = 0.9683561629982855 b1 = -1.9623510010064973 b2 = 0.9630467484871436
-8dB  a0 = 0.992235390556079  a1 = -1.95802200238334   a2 = 0.9661345115778704 b1 = -1.957759009927104  b2 = 0.9586328945901855
-10dB a0 = 0.9896816725117257 a1 = -1.9529826375649526 a2 = 0.9636479694136102 b1 = -1.952607477676734  b2 = 0.9537048018135545


Highshelf: Samplerate = 50kHz, Fc = 2500

+10dB a0 = 2.870667425597914   a1 = -5.023224213624618  a2 = 2.23289025028355    b1 = -1.5610180758007182 b2 = 0.6413515380575632
+8dB  a0 = 2.315290313906118   a1 = -3.981827659736173  a2 = 1.7468708080869002  b1 = -1.5610180758007182 b2 = 0.6413515380575632
+6dB  a0 = 1.870777426754878   a1 = -3.1546169734380136 a2 = 1.3641730089399804  b1 = -1.5610180758007182 b2 = 0.6413515380575632
+4dB  a0 = 1.5146926470714037  a1 = -2.4975401692457355 a2 = 1.0631809844311764  b1 = -1.5610180758007182 b2 = 0.6413515380575632
+2dB  a0 = 1.2291745832283425  a1 = -1.9756055112934103 a2 = 0.8267643903219126  b1 = -1.5610180758007182 b2 = 0.6413515380575632
0dB   a0 = 1                   a1 = -1.5610180758007182 a2 = 0.6413515380575632  b1 = -1.5610180758007182 b2 = 0.6413515380575632
-2dB  a0 = 0.8135540822635373  a1 = -1.2699726280548462 a2 = 0.5217741619527289  b1 = -1.6072619286550969 b2 = 0.6726175448165166
-4dB  a0 = 0.6601999434891688  a1 = -1.030584045429205  a2 = 0.42342024918229465 b1 = -1.6488758785979634 b2 = 0.7019120258402215
-6dB  a0 = 0.5345371318354201  a1 = -0.8344221249817622 a2 = 0.34282621165152505 b1 = -1.686259909020889  b2 = 0.7292011275260719
-8dB  a0 = 0.43191127868232804 a1 = -0.6742213131653154 a2 = 0.27700696288731985 b1 = -1.7197962760093122 b2 = 0.7544932044136448
-10dB a0 = 0.34835104585189497 a1 = -0.5437822792988928 a2 = 0.22341547904107353 b1 = -1.7498454083646984 b2 = 0.777829653958774
