21. Most of today's appliances produce sound pressure levels between 45 and 120 decibels at ten feet. 22. Doing so can alter their frequency response and cause distortion, especially at high sound pressure levels. 23. In air, sound pressure can be measured using a microphone, and in water with a hydrophone. 24. Without a specified reference sound pressure , a value expressed in decibels cannot represent a sound pressure level. 25. Without a specified reference sound pressure, a value expressed in decibels cannot represent a sound pressure level. 26. The speaker cone also generates more sound pressure , delivering more dynamic range and detail to the microphone. 27. The glossary in the file does have an entry for " sound pressure level ", which is 28. Sound Pressure is measured inside the vehicle.29. The design process starts by entering the dimensions of the room and the required sound pressure level. 30. Sirens generate low frequencies, but with high sound pressure levels distortion appears that leads to higher harmonics.
