11. The design process starts by entering the dimensions of the room and the required sound pressure level . 12. Sirens generate low frequencies, but with high sound pressure levels distortion appears that leads to higher harmonics. 13. The glossary in the file does have an entry for " sound pressure level ", which is 14. From an acoustics class I took, I remembered there were sound pressure levels , maybe unweighted or using A-weighting. 15. Additionally, discharge of firearms in indoor ranges can produce noise levels of over 140 dB sound pressure level . 16. :Go to Radio Shack or whatever your local electronics store is and pick up a sound pressure level meter. 17. Statistically significant health effects did however start as early as from an average sound pressure level of 40 decibel. 18. Else, how would you know the sound pressure level ? talk ) 20 : 59, 7 April 2009 ( UTC) 19. Other shortcomings include very limited sound pressure levels , meaning that it won't play loud, and its bass response was lacking. 20. Subwoofers also vary in regard to the sound pressure levels achievable and the distortion levels they can produce over their range.
