1 / 9

Loudness

Loudness. Power, intensity, intensity level,. Power and intensity. Sound detector. 1J=1Nm. Energy: will accumulate in time. 1W=1J/s. Power: rate of energy transfer, stays the same. Dependent on detector area. 1 W/m 2 =1J/sm 2. Intensity: rate of energy transfer per area.

aziza
Download Presentation

Loudness

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Loudness Power, intensity, intensity level,

  2. Power and intensity Sound detector 1J=1Nm Energy: will accumulate in time 1W=1J/s Power: rate of energy transfer, stays the same Dependent on detector area 1 W/m2=1J/sm2 Intensity: rate of energy transfer per area

  3. Inverse Square Law B radius B = 2 radius A A area B = 4 area A intensity B = 1/4 intensity A

  4. Sound intensity level • Physiological response to loudness does not simply scale with intensity • Loudest possible sound waves: • 1 Watt / square meter • Softest perceptible sound: • 10-12 Watt / square meter • Chosen as reference intensity

  5. Sound intensity level • 1 Decibel=1/10 bel (Alexander Graham Bell) • “1 bel” for a sound means: • the ratio of its intensity to a reference is 10:1 Decibel measure the relation between two sounds, not an amount of sound.

  6. Chart of sound levels

  7. Sound level and music • More than 50 dB (eliminates background) • Above 100 dB: damage to ears • ffff (95 dB) to ppp (50 dB) • More likely 60…85 dB for symphony concert • Determined by range of instruments (typically < 40dB) • Wood-wind: only 10 dB dynamic range

  8. Sound levels and multiple sources What is the resulting sound level L? Violinist A IA=60 dB Violinist B IB=60 dB 10-6 W/m2 10-6 W/m2 (60+Log2) dB = 63 dB 2∙10-6 W/m2

  9. Sound levels and multiple sources 10-6 W/m2 10-6 W/m2 10-6 W/m2 10-6 W/m2 10-6 W/m2 10-6 W/m2 10-6 W/m2 10-6 W/m2 10-6 W/m2 10-6 W/m2 What is the resulting sound level L? 10∙10-6 W/m2 10-5 W/m2 70 dB

More Related