37hz seems too high to tune type r's imo, but if you wanna go louder i guess //content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif i don't know the calculations or i'd help you out...actually i could prob find the calculations on the forums somewhere, but i gotta run to work. Ill check back after if no one has yet to respond...