Talk:Underwater acoustics

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Hello.... I think that "Underwater acoustics" and "Hydroacoustics" should be merged. It's the same thing. — Preceding unsigned comment added by 94.64.189.49 (talk) 14:27, 30 April 2018 (UTC)[reply]

Hello - I think that in some cases the additional sub-headings are unnecessary. I may change them - if you disagree, please respond here. Thanks, Hal peridol 01:40, 24 June 2007 (UTC)[reply]

I agree with Hal. There are too many subheadings in the Theory section, especially under Propagation of sound. I also think that the definitions of the sonar equation terms (eg source level, propagation loss, target strength) don't belong hear, but under sonar. Thunderbird2 00:14, 30 June 2007 (UTC)[reply]

I disagree. It is impossible to understand sound propagation underwater without these defining these terms. The idea of the subheadings was to allow a particular term to be quickly found. Adresia (talk) 11:26, 9 January 2008 (UTC)[reply]

History: Chinese sonar

Fishermen in ancient China predated Leonardo da Vinci; they listened to fish via a bamboo stick put into the water. (Source: Joseph Needham, "Science and Civilisation in China," volume 4, part 1, 1962; p. 210) Psalm 119:105 (talk) 08:13, 24 April 2009 (UTC)[reply]

Ambient Noise: Thermal Noise

I have seen many versions of a plot of ambient acoustic noise in water vs. frequency. Most of them include the feature described in this article, of the thermal noise power spectral density increasing by 20 dB per decade. Can anyone find a recent experimental or theoretical treatment of this phenomenon?Jay (talk) 18:16, 15 June 2011 (UTC)[reply]

See Mellen (1952) J Acoust Soc Am 24, 478-480. Dondervogel 2 (talk) 18:14, 14 June 2011 (UTC)[reply]

Thanks, I found that today re-reading Wenz. I think the crux of the issue is that there are three degrees of freedom in acoustic thermal noise, but only one in electrical noise. The formula with which I am familiar W=4kTB is a special case where there is only one degree of freedom. I think Mellen is original source of this feature so I left the text alone but added a reference to the Mellen paper after "The spectral density of thermal noise increases by 20 dB per decade (approximately 6 dB per octave)."Jay (talk) 18:16, 15 June 2011 (UTC)[reply]

Safety for humans

Mention if one just sticks their head in the water to do the underwater hearing, or should their ears be protected from water getting in, etc. 114.26.47.221 (talk) 10:45, 12 December 2013 (UTC)[reply]

Proposed merge of Hydroacoustics into Underwater acoustics

same concept fgnievinski (talk) 04:43, 6 March 2022 (UTC)[reply]

support merge. Hydroacoustics is a synonym of underwater acoustics. No brainer. Dondervogel 2 (talk) 21:42, 6 March 2022 (UTC)[reply]
A merge with redirect does appear generally appropriate, but some of the content of hydroacoustics may be better suited to merging into another article. Perhaps Sonar. See also a comment in Talk:Hydroacoustics#Untitled. Cheers, · · · Peter Southwood ^(talk): 04:43, 25 May 2022 (UTC)[reply]

Merger complete. Klbrain (talk) 23:53, 30 December 2022 (UTC)[reply]