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Compute underwater sound transmission loss from range



tl = range2tl(rng,freq,depth) returns the transmission loss, tl, for a sound wave of frequency freq arriving from a source at distance rng. The channel depth is depth. The transmission loss is due to geometrical spreading and frequency-dependent absorption. This function is the inverse of tl2range.


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Find the transmission loss (in dB) for a sonar operating at 2 kHz in a channel that is 200 m deep. The sound path is 1000.0 m long.

rng = 1000.0;
freq = 2000.0;
depth = 200;
tl = range2tl(rng,freq,depth)
tl = 50.1261

Input Arguments

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Distance from sound source to receiver, specified as a positive scalar. Units are in meters.

Example: 10e3

Data Types: double

Frequency of sound, specified as a positive scalar. Units are in Hz.

Example: 1e3

Data Types: double

Channel depth, specified as a positive scalar. Units are in meters.

Example: 200

Data Types: double

Output Arguments

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Transmission loss, returned as a positive scalar. Units are in dB.

Data Types: double


  • The transmission loss model assumes that seawater salinity is 35 ppt, pH is 8, and temperature is 10°C.

  • The transmission loss model is valid for frequencies less than or equal to 2.0 MHz.


[1] Ainslie M. A. and J.G. McColm. "A simplified formula for viscous and chemical absorption in sea water." Journal of the Acoustical Society of America, Vol. 103, Number 3, 1998, pp. 1671--1672.

[2] Urick, Robert J. Principles of Underwater Sound, 3rd ed. Los Altos, CA:Peninsula Publishing, 1983.

Extended Capabilities

Version History

Introduced in R2017b