Air Attenuation in Octave Bands and How to Normalize Room Acoustic Measurements to a Standard Atmosphere
Source abstract
Abstract
The air attenuation of pure tones as a function of temperature and humidity is well known and described in ISO and ANSI standards. However, room acoustic measurements are performed in octave bands, which is the reason for the complicated, non-linear behavior of the air attenuation. It is known that room acoustic measurement results depend on air temperature and humidity, and these atmospheric data should always be reported in connection with room acoustic measurements. A calculation model for the air attenuation can make it possible to normalize the room acoustic results. For accurate results, it is possible to apply a summation method on each time sample in the impulse response. An approximation to the air attenuation at and above 1 kHz is possible by linearization using the pure-tone attenuation of two different frequencies, one frequency valid for the early part of the impulse response and another frequency valid for the later part of the impulse response. The purpose of the suggested methods is to make it possible to normalize room acoustic measurements to a standard atmosphere.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Acoustic Wave Phenomena Research · Noise Effects and Management · Hearing Loss and Rehabilitation
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Odeon A/S, DTU Science Park, 2800 Kgs. Lyngby, Denmark
References (22)
Show source-provided references
1. (1993). Acoustics—Attenuation of Sound During Propagation Outdoors—Part 1: Calculation of the Absorption of Sound by the Atmosphere (Standard No. ISO 9613-1).
2. (2009). Acoustics—Measurement of Room Acoustic Parameters—Part 1: Performance Spaces (Standard No. ISO 3382-1).
3. Absorption of Sound in Air versus Humidity and Temperature10.1121/1.1910031 ↗
4. (1975). Acoustics—Measurement of Reverberation Time in Auditoria (Standard No. ISO 3382).
5. (1997). Acoustics—Measurement of Reverberation Time in Auditoria with Reference to Other Acoustical Parameters (Standard No. ISO 3382).
6. Cremer, L., and Müller, H.A. (1978). Die Wissenschaftlichen Grundlagen der Raumakustik, Band I, Hirzel. [2nd ed.].
7. Influence of atmospheric absorption on the propagation of bands of noise10.1121/1.383243 ↗
8. Effect of finite bandwidth on measured reverberation times10.1121/1.387563 ↗
9. (1995). American National Standard. Method for Calculation of the Absorption of Sound by the Atmosphere (Standard No. ANSI S1.26).
10. (1996). Acoustics—Attenuation of Sound During Propagation Outdoors—Part 2: General Method of Calculation (Standard No. ISO 9613-2).
11. (2003). Building Acoustics—Estimation of Acoustic Performance of Buildings from the Performance of Elements—Part 6: Sound Absorption in Enclosed Spaces (Standard No. EN 12354-6).
12. Wenmaekers, R.H.C., Hak, C.C.J.M., Martin, H.J., and van Luxemburg, L.C.J. (July, January 29). Air absorption error in room acoustical modelling. Proceedings of the Acoustics, Paris, France.
13. The effective air absorption coefficient for predicting reverberation time in full octave bands10.1121/1.4901710 ↗
14. Variability of room acoustic parameters with thermo-hygrometric conditions10.1016/j.apacoust.2021.107933 ↗
15. Granzotto, N., Yan, R., and Tronchin, L. (2023). Measurements of Room Acoustic and Thermo-Hygrometric Parameters—A Case Study. Appl. Sci., 13.10.3390/app13052905 ↗
16. Room Acoustics Parameters in a Physical Scale Model of the New Music Centre in Eindhoven: Measurement Method and Results10.1016/0003-682X(94)90121-X ↗
17. Ćirić, D., Stevanović, Đ., and Pantić, A. (2010, January 15–18). Numerical Compensation of Sound Absorption in Air in Acoustical Measurements of Room Models. Proceedings of the EuroRegio, Ljubljana, Slovenia.
18. Effects of Humidity on the Velocity of Sound in Air10.1121/1.1912429 ↗
19. (1984). American National Standard. Preferred Frequencies, Frequency Levels, and Band Numbers for Acoustical Measurements (Standard No. ANSI S1.6).
20. (1975). Standard Atmosphere (Standard No. ISO 2533).
21. (2024, September 04). Available online: https://odeon.dk/pdf/OdeonOmniSpecifications.pdf.
22. The effects of air temperature and humidity on the acoustic design of voice alarm systems on underground stations10.1016/j.apacoust.2013.08.017 ↗