31. A microphone is distinguishable by the voltage value produced when a known, constant sound pressure is applied. 32. Interaural level differences ( ILD ) represents the difference in sound pressure level reaching the two ears. 33. In addition, microphones are not uniformly sensitive to sound pressure , and can accept differing levels without distorting. 34. A p-u type of sound intensity probe measured both the sound pressure and the particle velocity directly. 35. Additionally, discharge of firearms in indoor ranges can produce noise levels of over 140 dB sound pressure level. 36. Some phenomena linked to frequency of the sound pressure field lead to poor homogeneity of a pressure field. 37. In PCM, each audio sample describes the sound pressure at an instant in time with a limited precision. 38. The outer ear funnels sound vibrations to the eardrum, increasing the sound pressure in the middle frequency range. 39. Measured sound pressure was between 29 and 32dBA in idle mode and 31 to 34dBA during seek mode. 40. Ears detect changes in sound pressure .
