Talk:Sound power

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Z = c · ρ - Wrong!?[edit]

The table at Sound power with plain sound waves reads the following:

Symbol	Units	Meaning
Z = c · ρ	N·s/m³	acoustic impedance
p	Pa	sound pressure
ρ	kg/m³	density of air
c	m/s	speed of sound

Shouldn't it be Z = p/c, since Pa = N/m² ?

Because

(m/s) · (kg/m³) = kg / (m²·s)   != N·s/m³

(N/m²) / (m/s)  = (N/m²) · (s/m) = N·s/m³

Or did I miss something?

/Lord E (talk) 14:09, 14 September 2008 (UTC)[reply]

This is correct.

Specific acoustic impedance is $Z=\rho _{0}c_{0}$ (not sure why the ρ is funky in the math here.

Units work out as ${\frac {kg}{m^{3}}}{\frac {m}{s}}=(kg{\frac {m}{s^{2}}}){\frac {s}{m^{3}}}=N{\frac {s}{m^{3}}}$ --67.188.6.157 (talk) 08:01, 14 April 2010 (UTC)[reply]

Merger proposal[edit]

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.

Clear agreement on merge. -- P 1 9 9 • TALK 13:55, 22 March 2011 (UTC)[reply]

Sound power level should be merged into this article. --TheJokari (talk) 13:02, 25 September 2008 (UTC)[reply]

Agree. The level of sound power is an important aspect, but not enough to give it its own article. Binksternet (talk) 20:25, 25 September 2008 (UTC)[reply]

Agree. Sound power level is a ratio of sound power, and should be considered as part of the same topic Sam Lacey (talk) 20:09, 1 November 2009 (UTC)[reply]

Agree. And what about Sound pressure too perhaps? Plus relevant part of Threshold of pain This has been 'on the books' for 14+ months. Time to Be Bold --220.101.28.25 (talk) 13:09, 2 December 2009 (UTC)[reply]

Agree but this won't be a trivial merge. Sound power apparently refers to total power whereas Sound power level refers to a power per area. I'm not convinced that either term is particularly notable. Sound pressure level is what is commonly used in audio but I'm personally not clear on the connection between Sound power level and Sound pressure level. --Kvng (talk) 14:33, 23 August 2010 (UTC)[reply]

Agree Sound power level is just an expression of sound power in decibels (hence the use of the word level). It would be an easy merge - I think that Kvng is thinking of intensity, which is power over area. I disagree with 220.101.28.25 that sound pressure (or sound pressure level) and sound power should be combined. Ereuter (talk) 23:43, 27 October 2010 (UTC)[reply]

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Threshold of pain?[edit]

I was wondering if on the "Sound power and sound power level of some sound sources" table, for the 120 dB row, if we could add the threshold of pain. There are various definitions for the threshold, but since 120 seems to be the most common, I think it should be included. Also, just for consistency's sake, since the auditory thresholds are included, why not include the threshold of pain? I just wanted to make sure it would be ok to add. Thanks! Hsh8 (talk) 15:23, 16 June 2009 (UTC)[reply]

Check out the Threshold of pain article stub. It needs references! I'm not next to my bookshelf right now but I am remembering that the threshold of pain is frequency dependent, such that very, very loud low frequencies aren't as painful as very, very loud mids. Also, temporary threshold shift can occur in listeners who have been in the presence of loud sound for a little while, so that the threshold of pain can shift up to 130 dB or so for that person. Temporary threshold shifts from 5 to 20 dB have been observed, but an average value of 10 dB is present in much of the literature. Anyway, 120 dB is indeed the starting point for un-shifted listeners to experience pain.

www.ncrar.research.va.gov/AboutUs/Staff/Documents/Konrad-Martin_Comparing_Audiometric.pdf
www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=standards&p_id=9735 -

Cheers - Binksternet (talk) 16:07, 16 June 2009 (UTC)[reply]

OK! I'll see what I can do for the Threshold of pain stub, in terms of references. Thank you for your help! Hsh8 (talk) 16:22, 16 June 2009 (UTC)[reply]

Another merge proposal[edit]

Sound power and Sound energy flux are measured in the same units (Watts) and appear to be measuring the same thing. I propose to merge Sound energy flux into this article. -—Kvng 20:06, 16 December 2012 (UTC)[reply]

Support. It helps prevent confusion with flux measured in W/m^2 as well. Forbes72 (talk) 22:07, 28 March 2015 (UTC)[reply]

This Article is a scientific disaster[edit]

The first section is Correct

After That it goes into Nonsense.

...Agreed, are you helping to revise it? Hopefully I will have time to do part. Altaphon (talk) 04:52, 16 April 2019 (UTC)[reply]

The second section confuses Sound Power & Sound Intensity

Sound Power is the TOTAL energy emitted by a source Sound Intensity is the level Delivered at some specific place ( Closer=Louder! )

...Let's not introduce that confusion. Sound intensity is sound power through a unit area. Sound pressure is pressure at a given point. Altaphon (talk)

The Chart and it's reference also confuse Power & Intensity

The right column is a list of Intensity (Sound Pressure Level) at some unstated distance NOT Sound Power Level as it is labeled

The "Watt" column is a back calculation based upon the false assumption that the Ear's sensitivity is measured in Watts

Anyone who thinks the acoustic power of a thunderclap is only ONE WATT has never felt the effects from a mile away.

If a Car Stereo with 20 Watts of amplifier power and 5% efficiency speakers could shake the earth a mile away, why would Factory Stereos have hundreds of Watts and aftermarket ones Thousands of Watts. ...Because the conversion from mechanical watts to acoustic watts is very poor. Altaphon (talk) 04:52, 16 April 2019 (UTC)[reply]

And of course Symphony Orchestras are 10x louder than Rock Concerts... NOT

The Priority of reviewing this article needs to be stepped up or at least some statement that this article is NOT verified. I actually came across a forum where people were trying to figure out acoustics calculations and believed this to be Factual information and were quoting it. 75.27.41.149 (talk) 03:39, 20 March 2018 (UTC)[reply]

Commons files used on this page have been nominated for deletion[edit]

The following Wikimedia Commons files used on this page have been nominated for deletion:

Participate in the deletion discussion at the nomination page. —Community Tech bot (talk) 03:07, 21 October 2018 (UTC)[reply]

Recent edits[edit]

I just reverted a bunch of recent changes. The first edit of the sequence made on 16 April was incorrect (because the concept of power is not limited to sound radiated by a source), so I tried to revert only that edit, but was unable to. I'm sure the article can be improved, but please make a suggestion on the talk page before implementing. Dondervogel 2 (talk) 07:19, 16 April 2019 (UTC)[reply]

It is not incorrect, it may be incomplete, and I fully intend to add more information. I think it's an improvement to the mashup that's there now. I'm unaware of the requirement to pass editorial review in Talk before making improvements - if that's the case please provide a reference. Sound power is defined (ISO 80000-8) as "through a surface, product of the sound pressure, and the component of the particle velocity, at a point on the surface in the direction normal to the surface, integrated over that surface." The most general use is in measuring the sound power emitted by a source, irrespective of distance. Altaphon (talk) 04:49, 17 April 2019 (UTC)[reply]

Right, per WP:BRD, your "bold" edit was OK, but when it was objected to and reverted, it's time to discuss. Dicklyon (talk) 05:49, 17 April 2019 (UTC)[reply]

I agree with Dondervogel that measuring the power emitted by a source is not the "most general use", but is a particular use of the power concept. Dicklyon (talk) 05:51, 17 April 2019 (UTC)[reply]

Yes, BRD is a good rule, and my revert was intended in that spirit. I did not mean to imply otherwise. The ISO definition seems fine, and the power of a source is an important application of that definition. Another application is the power reflected, transmitted or absorbed by a wall. Dondervogel 2 (talk) 06:10, 17 April 2019 (UTC)[reply]

Table of sound powers[edit]

An editor stated some concerns about the top few lines of the table, but a discussion of this sort without supporting citations belongs on the talk page. I am reproducing it here:

"The top three or four lines seem questionable. A 150-dB source should be audible 100 times as far away as a 110-dB source, and a 200-dB source 10 000 times further than a 120-dB source. This would imply that a turbofan aircraft at take-off would be audible 100 times further than a rock concert, and a Saturn V 10 000 times further than heavy thunder. This doesn't seem to be the case, at least not when the sound has to travel along the surface of the earth."

RockMagnetist(talk) 17:02, 4 February 2020 (UTC)[reply]

Sound power[edit]

S 182.50.65.201 (talk) 11:32, 18 December 2022 (UTC)[reply]