Talk:Rayl

rayl or Rayl?

I would have used a lower case "r" for both the name and the symbol but I'm not sure. I suspect that the MKS version is not standardized because it is not part of the SI, but I will look out for a standard definition of the original CGS unit. Thoughts anyone? Dondervogel 2 (talk) 10:15, 6 December 2014 (UTC)

I certainly see where you're coming from, but in the two reference works I consulted, 'Rayl' and 'Rayleigh' were used (see the refs in the first line). Oreo Priest ^talk 10:59, 6 December 2014 (UTC)

I found this definition of impedance in ANSI S1.1-2013 Acoustical Terminology

6.35 specific acoustic impedance, characteristic acoustic impedance. At a point in a medium, the complex ratio of sound pressure to particle velocity in the direction of the wave propagation. Unit, pascal per (meter per second) [Pa/(m/s)].

NOTE 1 In the MKS system of units, 1 rayl is equal to 1 pascal per (meter per second). An acoustic impedance of 1 rayl results from the application of 1 pascal of sound pressure producing a particle velocity of magnitude 1 meter per second.

NOTE 2 In the CGS system, 1 rayl is equal to 1 (dyn·s)/cm³, which is equal to 10 rayls in the MKS

system.

This backs up the dual (and ambiguous) MKS-CGS definitions, and uses the name "rayl", not "Rayl". Dondervogel 2 (talk) 11:06, 6 December 2014 (UTC)

Here are some more, from Morfey's Dictionary of Acoustics

• rayl - see SI rayl. The original rayl was defined as a cgs unit of specific acoustic impedance, equal to 1 dyn s cm^-3
• SI rayl - 1 N s m^-3 = 1 Pa s m^-1 ... Not a recognized SI derived unit, despite its name.

Again, lower case "r". Dondervogel 2 (talk) 15:47, 6 December 2014 (UTC)

Interesting. Well, this at least shows that use is mixed! Oreo Priest ^talk 22:58, 6 December 2014 (UTC)

On acoustic impedance it is spelt "rayl". Regardless of whether it is "rayl" or "Rayl", I think it should be the same in both articles. Do you agree? I have left a note on the impedance talk page advertising the existence of this discussion. Dondervogel 2 (talk) 23:39, 6 December 2014 (UTC)

rayl or Rayl revisited (2024)

Dondervogel 2, is 'rayl' is more common than 'Rayl'? AFAICT, it is the other way around since about 2010 and rather dominant since 2020. —Quondum 01:17, 29 January 2024 (UTC)

My statement was based on the books I have at home. The first 4 I checked all use "rayl" so I stopped looking. Those 4 were published between 1962 and 2010, so the two observations are not in conflict. I'll try Google Scholar. Dondervogel 2 (talk) 08:22, 29 January 2024 (UTC)

Of the first 9 hits on Scholar, 8 use "MRayl" and 1 uses a mixture of "MRayl" and "Mrayl", which is consistent with your ngram findings. The question becomes whether modern use of this rare unit trumps solid earlier sources. One of the 4 books I consulted was Morfey's Dictionary of Acoustics (published 2001), which I hold in high esteem. Dondervogel 2 (talk) 08:31, 29 January 2024 (UTC)

By the way I just noticed the preceding 2014 discussion, only after posting the above 2 messages. If there is a consensus for using "Rayl", I can live with that, but let's have the discussion here and then make any change consistently also in Acoustic impedance. Dondervogel 2 (talk) 08:49, 29 January 2024 (UTC)

My personal preference would be to keep 'rayl' (partly because I think that is where it will settle anyway: serious metrology has a trend towards decapitalizing unit names – maybe especially when these are pretend-SI, it looks to be a unit that will remain in use as an unaccepted unit name coherent with the SI, and capitalization will not end up being a disambiguator in this case). And I am particularly suspicious of the recent ngram dominance of 'Rayl' in books (and even more so the Google Scholar papers), possibly being driven by what was on Wikipedia. This: I would support paring down the sources to the most reputable/reliable established post-2000 scholarly books only, excluding anything related to commerce (products, manuals, company literature). I only raised this because the crude stats point to looking into it. —Quondum 13:43, 29 January 2024 (UTC)

Is this about the name of the unit or its symbol? The SI convention would be to use lc for the name (rayl) and uc for the symbol (Rayl, MRayl). Dondervogel 2 (talk) 15:59, 29 January 2024 (UTC)

Good point – that I forgot about this shows just how little I have been looking at unit-related things of late. I guess following the SI convention would make sense (which would mean adapting the use in the article, since symbols should appear in expressions), so if we can find that capitalization follows this convention in enough reliable sources, we could make this clear. I'm afraid I'm not volunteering to do in-depth research :/ , so if you're feeling keen, go ahead. —Quondum 17:50, 29 January 2024 (UTC)

I ain't about to embark in in-depth research either, but I can provide verbatim quotes from the 4 books I mentioned previously:

• Kinsler et al 1961 (p122): The MKS unit of specific acoustic impedance is a kilogram/meter² second or rayl (MKS rayl).
• Beranek 1986 (p11)

  The unit [of specific acoustic impedance] is newton-sec/m³, or the mks rayl. (In the cgs system the unit is dyne-sec/cm³, or the rayl.) That is, Z_s = p/u newton-sec/m³ (mks rayls)

  The unit [of characteristic impedance] is the mks rayl, or newton-sec/m³. (In the cgs system, the unit is the rayl, or dyne-sec/cm³.)

  In the solution of problems in this book we shall assume for air that ρ₀c = 407 mks rayls (or ρ₀c = 40.7 rayls) ...

• Morfey 2001 (pp 308, 341)

  rayl - see SI rayl. The original rayl was defined as a cgs unit of specific acoustic impedance, equal to 1 dyn s cm^-3

  SI rayl - 1 N s m^-3 = 1 Pa s m^-1 ... Not a recognized SI derived unit, despite its name

• Ainslie 2010 (p662)

  MKS rayl - See rayl

  rayl (symbol: dyn s/cm² [sic]; SI equivalent: 10 Pa s/m) - One pascal second per meter (1 Pa s/m) is sometimes known as an "MKS rayl". The rayl is not an SI unit

Dondervogel 2 (talk) 19:10, 29 January 2024 (UTC)

If only the real world were as tidy as the systems that we retrospectively try to impose on it. What I see in that is that there is a name (lower-case 'rayl'), which is generally qualified with "MKS" or "SI" for the SI-coherent unit, and no symbol (other than a combination of recognized units in each system). Yet, it is evident that people use the capitalized form as a symbol at times from the searches. So I went out on a limb and put in what we are seeing (as well as being systematic), even if it is not as solidly researched. —Quondum 21:45, 29 January 2024 (UTC)

If you're feeling energetic, a couple of references that you list for the lower-case unit name would make sense. Given time, I could sleuth out the full reference details using Google Scholar or similar. —Quondum 21:55, 29 January 2024 (UTC)

The reference for Morfey (from Google Scholar) is Morfey, C. L. (2000). Dictionary of acoustics. Academic press. I'll try to dig out the others tomorrow. Dondervogel 2 (talk) 23:17, 29 January 2024 (UTC)

Here are the other 3:

• L E Kinsler & A R Frey, Fundamentals of Acoustics, 2nd edition (Wiley, 1962)
• L L Beranek, Acoustics (American Institute of Physics, 1986)
• M A Ainslie, Principles of Sonar Performance Modeling (Springer, 2010)

Dondervogel 2 (talk) 10:31, 30 January 2024 (UTC)

As an afterthought, unless 'Rayleigh' is used fairly widely as the unit name (say at least 10% of the total authoritative use with this meaning), I would incline to remove any mention of it. It is unnecessary and just muddies the waters, including though its conflict with the raleigh, the unit of photon flux. —Quondum 14:00, 29 January 2024 (UTC)

I have never seen 'rayleigh' (or 'Rayleigh') used (as a unit of acoustic impedance) outside of Wikipedia. I would be pleased to see it gone. Dondervogel 2 (talk) 16:01, 29 January 2024 (UTC)