声压
维基百科，自由的百科全书
| 声音的衡量 |
|---|
| 声压 p, SPL |
| 粒子速度 v, SVL |
| 粒子位移 ξ |
| 声强 I, SIL |
| 声功率 Pac |
| 声能级 SWL |
| 声能密度 E |
| 声能通量 q |
| 声阻抗 Z |
| 声速 c |
| 声频 AF
|
声压（acoustic pressure）是指声波通过某种媒质时，由振动所产生的压强改变量。就声波在空气中传播而言，空气的疏密程度会随声波而改变，这样，空气的压强也会随之改变，即在原有大气压的基础上又产生了一个随声波变化的交变压强，此交变压强即为声压。声压常用字母 "p" 表示，在国际单位制中，声压的衡量单位是帕斯卡（符号Pa）。
声压级（SPL）是指以对数尺衡量有效声压相对于一个基准值的大小，用分贝（dB）来描述其与基准值的关系。人类的对于 1KHz 的声音的听阈（即产生听觉的最低声压）为 20µPa，通常以此作为声压级的基准值。
Examples of sound pressure and sound pressure levels [编辑]
Sound pressure in air:
| Source of sound | Sound pressure | Sound pressure level |
|---|---|---|
| Sound in air | pascal RMS | dB re 20 μPa |
| Shockwave (distorted sound waves > 1 atm; waveform valleys are clipped at zero pressure) | >101,325 Pa | >194 dB |
| Theoretical limit for undistorted sound at 1 atmosphere environmental pressure | 101,325 Pa | ~194.094 dB |
| Stun grenades | 6,000–20,000 Pa | 170–180 dB |
| Rocket launch equipment acoustic tests | ~4000 Pa | ~165 dB |
| Simple open-ended thermoacoustic device[1] | 12,619 Pa | 176 dB |
| .30-06 rifle being fired 1 m to shooter's side | 7,265 Pa | 171 dB (peak) |
| M1 Garand rifle being fired at 1 m | 5,023 Pa | 168 dB |
| Jet engine at 30 m | 632 Pa | 150 dB |
| Threshold of pain | 63.2 Pa | 130 dB |
| Vuvuzela horn at 1 m | 20 Pa | 120 dB(A)[2] |
| Hearing damage (possible) | 20 Pa | approx. 120 dB |
| Jet engine at 100 m | 6.32 – 200 Pa | 110 – 140 dB |
| Jack hammer at 1 m | 2 Pa | approx. 100 dB |
| Traffic on a busy roadway at 10 m | 2×10−1 – 6.32×10−1 Pa | 80 – 90 dB |
| Hearing damage (over long-term exposure, need not be continuous) | 0.356 Pa | 85 dB[3] |
| Passenger car at 10 m | 2×10−2 – 2×10−1 Pa | 60 – 80 dB |
| EPA-identified maximum to protect against hearing loss and other disruptive effects from noise, such as sleep disturbance, stress, learning detriment, etc. | 70 dB[4] | |
| Handheld electric mixer | 65 dB | |
| TV (set at home level) at 1 m | 2×10−2 Pa | approx. 60 dB |
| Washing machine, dish washer | 50-53 dB | |
| Normal conversation at 1 m | 2×10−3 – 2×10−2 Pa | 40 – 60 dB |
| Very calm room | 2×10−4 – 6.32×10−4 Pa | 20 – 30 dB |
| Light leaf rustling, calm breathing | 6.32×10−5 Pa | 10 dB |
| Auditory threshold at 1 kHz | 2×10−5 Pa | 0 dB[3] |
参考资料 [编辑]
- ^ Hatazawa, M., Sugita, H., Ogawa, T. & Seo, Y. (Jan. 2004), ‘Performance of a thermoacoustic sound wave generator driven with waste heat of automobile gasoline engine,’ Transactions of the Japan Society of Mechanical Engineers (Part B) Vol. 16, No. 1, 292–299. [1]
- ^ Swanepoel, De Wet; Hall III, James W; Koekemoer, Dirk. Vuvuzela – good for your team, bad for your ears (PDF). South African Medical Journal. 2010.February, 100 (4): 99–100. PMID 20459912.
- ^ 3.0 3.1 William Hamby. Ultimate Sound Pressure Level Decibel Table. （原始内容存档于2010-07-27）.
- ^ EPA Identifies Noise Levels Affecting Health and Welfare. 1974-04-02 [2010-11-01]
