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![]() | The contents of the Binaural beats page were merged into Beat (acoustics). For the contribution history and old versions of the redirected page, please see its history; for the discussion at that location, see its talk page. |
![]() | The contents of the Monaural beats page were merged into Beat (acoustics). For the contribution history and old versions of the redirected page, please see its history; for the discussion at that location, see its talk page. |
Can someone verify, if the example is legit? For all other sounds I heard the pulse, when listening with both earphones and stopped hearing the pulse, when listening with only one earphone. But for the "220/222 Hz example" I always hear the pulse, no matter what earphone I use. — Preceding unsigned comment added by 2003:FB:F1B:3BE3:115D:BEF5:D683:B387 ( talk) 08:07, 26 June 2023 (UTC)
I just changed the identity to read 4a on the right. This is correct isn't it? Also, why the amplitude in terms of 2a in the first place? Couldn't it be simplified to read just a? -- postglock 15:52, 16 August 2005 (UTC)
Not sure if it's worth mentioning, but the two guitar strings "we" have tuned to the same note won't be exactly the same, since they have different stiffnesses and therefore different partials or timbres.
Also, you're not supposed to talk to the reader in encyclopedic tone. — Omegatron 02:23, 29 January 2006 (UTC)
The article states that "the beating frequency is f1−f2, the difference between the two starting frequencies". However, if one takes the equation above, , one can argue that the beating frequency is actually . In the term , the frequency is (i.e. take the term inside the cosine function and divide it by ). This can be verified quickly using Octave or Matlab.
I find the justifying equation quite daunting until you realize that, for the sake of simplicity, most constants can be ignored. In addition, a variable change gets rid of the two fractions and make things clearer.
This is what I propose:
Well, I think this reads better than the original:
We could also make the transformation explicit:
(Here, the "+" should be indetend further than the two "=", while retaining proper alignment of the two upper terms, but I don't know how to do that) Exxos77 21:40, 25 May 2007 (UTC)
For an example in music, popular American punk band At the Drive-in have a song called "pickpocket" which uses notes a step apart to create beating. It's most prominent in the introduction of the song. 129.11.122.215 14:04, 22 September 2007 (UTC)
Alvin Lucier also has several pieces that explore beats. —Preceding unsigned comment added by 82.23.210.169 ( talk) 16:39, 19 January 2008 (UTC)
Practically all accordion music, espacially the French (mussette) uses beats in their music, they have two sets of reeds wich are tuned slightly different to create this effect. The difference goes from 1Hz (slow mussette/beats) to 5 or 6 Hz (fast mussette/beats). —Preceding unsigned comment added by 78.29.204.69 ( talk) 15:49, 12 July 2008 (UTC)
It is said: "This is caused by slight differences between the intervals of equal temperament and the "natural" intervals of the harmonic series". While this is, strictly speaking, possible, that's not what I had in mind when I originally wrote that sentence back in... (Who cares when?). I was thinking about out-of-tune notes. In the specific example of a fifth, using for example C4 and G4, the third harmonic of the former is 784.88 Hz and the second harmonic of the latter is 783.99 Hz. They beat at less than 1 hertz, and most times notes are played for much shorter than 1 second. Also, the interval between a just-intonation fifth and an equal-temperament fifth is less than two cents, while the just noticeable difference for the human ear is 5 cents, so it means that in practice often instrument aren't tuned to such accuracy.
On the other hand, should the G4 be 15 cents too sharp, its second harmonic would be 790.81 Hz, beating at almost 6 Hz and immediately noticeable.
So the inexactness of ET, if mentioned, should be introduced as a possible cause of beating (e.g. "This can also be caused"...), and a "worse" interval (e.g. the ET major third at −14 cents from the exact one) should be used for the example. Army1987 ( talk) 11:06, 15 June 2008 (UTC)
This material appears in many undergraduate physics texts. Just for grins, how about citing a couple...? Rb88guy ( talk) 19:07, 4 September 2009 (UTC)
(moved from User talk:Oli Filth)
You deleted my bit on doppler-shift ultrasound in the beats section, saying that it was probably irrelevant. It's not! Beats is exactly what is used to observe and measure the small frequency shift between reference signals and those reflected. Do you want to argue this further? I'd be happy to... —Preceding unsigned comment added by Bhindibhagee ( talk • contribs) 14:54, 20 April 2010 (UTC)
There was a section on "difference tones" that contained the following unsourced content:
"If the beating frequency rises to the point that the envelope becomes audible (usually, much more than 20 Hz), it is called a difference tone.[citation needed] The violinist Giuseppe Tartini was the first to describe it, dubbing it il Terzo Suono (Italian for "the third sound"). Playing pure harmonies (i.e., a frequency pair of a simple proportional relation, like 4/5 or 5/6, as in just intonation major and minor third respectively) on the two upper strings of a violin, such as the C above middle C against an open E-string, will produce a clearly audible C two octaves lower. An interesting listening experiment (help·info) is to start from a perfect unison and then very slowly and regularly increase the pitch of one tone. When one tone starts to split out from the former twin-note, a slow rumbling can be heard, gradually increasing into an audible tone."
This is completely incorrect. An obvious counterexample would be to take a 100 Hz sine wave sin(100*2pi*t) and modulate it by another 100 Hz sine wave sin(100*2pi*t). Since the envelope is 100 Hz, by this (completely unsourced) theory, we should hear a 100 Hz audible tone in the result. Obviously, we don't; a 100 Hz tone is present neither mathematically nor audibly via naive experiment. sin(100*2pi*t)^2 = 1/2 - 1/2*cos(200*2pi*t), so what we end up getting is a 200 Hz tone with some DC offset.
Given a signal s(t) and an envelope e(t), it's a very, very common but *completely wrong* misconception that the spectral content of the envelope is present in the combined signal s(t)*e(t), which leads to the further misconception that if e(t) becomes fast enough to "be audible," you'll hear it. This is only true if s(t) has a nonzero frequency response at DC, and is false otherwise. You can see some computed AM spectra at [3], which clearly shows that the spectral content of the modulator isn't present in the mixed signal.
Another reason that the "envelope" might "become audible" is if some nonlinear system is present which is actually creating intermodulation distortion, e.g. literal sum and difference tones. This is a *completely* different phenomenon from beating and should never be confused with it.
I've deleted this entire section; I don't know how to salvage it.
Battaglia01 ( talk) 01:27, 3 April 2013 (UTC)
In one of the samples, it is written that frequencies 300 and 310 produce a beat frequency of 12.35 Hz. This is obviously not correct. It goes on to say that 300 Hz is the A3 tone and that 310 is the G#3 tone. These frequencies are not correct. And furthermore, why would G# be *higher* than A3? The description of this sample is incorrect in so many ways. I'm going to remove the description entirely, but I will leave the sample in case anyone cares to figure out which two frequencies are really beating against each other. — Preceding unsigned comment added by 198.182.13.47 ( talk) 14:37, 30 October 2015 (UTC)
This image from another article:
could be used or adapted for use in this article. 71.166.96.62 ( talk) 19:07, 26 November 2015 (UTC)
The comment(s) below were originally left at Talk:Beat (acoustics)/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
As a lay person and a person unfamiliar with musical terms, I found this article difficult to read and rather a bit daunting. The beat's definition needs some further explanation or rephrasing in order to ease comprehension and understandability. The article attempts to describe what beating is and runs into complications when giving a definition. This is because beating is a sound and the text is giving a mental picture of what that sound is. The two are not too related and So that the definition is understood a very clear explanation must be supplied. |
Last edited at 09:52, 27 April 2008 (UTC). Substituted at 09:17, 29 April 2016 (UTC)
I think the picture at the top is misleading. ( https://upload.wikimedia.org/wikipedia/commons/2/2e/Beating_Frequency.svg). It looks like there are 2 signals multiplied together, not added as happens with beats. Also, the values used in the formulas don't give a clear picture of how the beating frequency is calculated. Am I missing something or should this picture be changed? — Preceding unsigned comment added by 2602:306:B8BC:3300:11A9:F1AE:4DF3:6D36 ( talk) 22:55, 23 October 2017 (UTC)
The idea that the beat takes place between the two ears needs references.
I could be that just the amplitude increasing and decreasing could entrain brain waves - but only this paper shows that the two ears are needed : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2741401/
more links: http://www.stealthskater.com/Documents/Lucid_07.pdf <redacted>
The next link is a key source of the phenomena:
<redacted> — Preceding unsigned comment added by 108.243.106.82 ( talk) 15:16, 19 December 2017 (UTC)
Can someone check the validity of the explanations given in the binaural beats section? The example in the text and the two sound files imply that the slightly discordant tones produce the illusion of hearing a third tone of 10 Hz or 3 Hz or 2 Hz. But the lower threshold of human hearing is 20 Hz, so an illusion of hearing those lower frequencies would be the illusion of hearing nothing, no? Largoplazo ( talk) 02:01, 26 January 2018 (UTC)