Energy Time Curve

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The diagram shows a typical Energy Time Curve (ETC) in an acoustically not optimized room.

The Energy Time Curve (also referred to as Envelope), abbreviated to ETC, is used in room acoustics to evaluate the relationship between direct sound and diffuse sound . To measure the ETC, the sound pressure level (in dB) is plotted over time (in ms). This results in a curve which shows the reverberation of a pulse at the measurement position over time.

The highest high points of the resulting curve correspond to the highest sound pressure levels and thus to a strong early reflection . On the basis of the time at which a certain high point occurs, the transit time difference of this reflected signal compared to the output signal can be calculated. This enables the source for the reflection to be identified . By doing this, all sources of strong early reflections can be identified. In rooms that are used for loudspeaker reproduction, the amplitude of the reflection signals should be at least 20 dB lower than the output signal (corresponds to the blue line in the adjacent diagram). This ensures that the reflections that occur do not negatively affect the sound. This can be achieved by attenuating the reflection sources determined. It is important, however, that not only the broadband signal is considered, but also the behavior in individual band areas

literature

  • Andreas Friesecke: The audio encyclopedia: a reference work for sound engineers . Walter de Gruyter, 2007, ISBN 3-598-11774-4
  • Christian Jungebluth: Room acoustics in control rooms. from chap. 6: Measurement parameters. Technical thesis (SAE Cologne - AEDP 0302) July 8, 2003 (online) (PDF; 3.4 MB)
  • David Howard, Jamie Angus: Acoustics and Psychoacoustics . CRC Press 2013, ISBN 1-136-12157-9

Web links

Individual evidence

  1. ^ Andreas Friesecke: Die Audio-Enzyklopädie: a reference work for sound engineers , p. 869. Retrieved on May 17, 2013 .
  2. ^ David Howard, Jamie Angus: Acoustics and Psychoacoustics , 7.3. Retrieved May 17, 2013 .
  3. ↑ ETCs. Retrieved November 10, 2019 .