Timeline for Why are pure tones depicted as sine waves?
Current License: CC BY-SA 3.0
18 events
| when toggle format | what | by | license | comment | |
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| May 10, 2016 at 14:42 | answer | added | guidot | timeline score: 0 | |
| May 8, 2016 at 7:51 | history | edited | user108262 | CC BY-SA 3.0 |
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| May 8, 2016 at 2:13 | answer | added | Geremia | timeline score: 3 | |
| May 13, 2015 at 19:18 | history | tweeted | twitter.com/#!/StackMusic/status/598568070140010496 | ||
| May 11, 2015 at 21:51 | vote | accept | user108262 | ||
| May 11, 2015 at 5:59 | answer | added | aparente001 | timeline score: 0 | |
| May 10, 2015 at 17:45 | history | edited | Doktor Mayhem♦ | CC BY-SA 3.0 |
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| May 10, 2015 at 17:36 | comment | added | Myridium | The y axis represents air pressure or air displacement (they are 90 degrees out of phase) at a fixed point in space. Cosine is the same thing, just shifting the time axis along a little bit. In fact, any combination of sines and cosines of the same frequency will give you a pure tone. | |
| May 10, 2015 at 14:30 | comment | added | peterG | The maths and physics of this have been well handled in the replies, so I'm just going to throw in something from a totally different perspective, that of musical perception: if you listen to different tones, or sounds of different timbres, (eg with an analog synth) and look at their waveforms on an oscilloscope, you will immediately see that those that sound like 'pure tones' appear as sinewaves on the scope - so it's not that they are 'depicted' as sinewaves, they 'are' sinewaves. ie what we perceive intuitively as a pure tone maps across to the maths as per the other answers. | |
| May 10, 2015 at 8:00 | answer | added | user20319 | timeline score: 11 | |
| May 10, 2015 at 7:46 | answer | added | Todd Wilcox | timeline score: 15 | |
| May 10, 2015 at 7:15 | comment | added | Todd Wilcox | I just have to say, it's "beaten track", not "beat and track". "Beaten" as in "beaten down by many passing feet over a long period of time". The beaten track is the road well-travelled. Going down the beaten track is following the same path taken by many before you. Going off the beaten track is striking out through the weeds, undergrowth and forest. It may be dangerous, uncomfortable, or lonely, but it also likely involves going where no one has gone before. | |
| May 10, 2015 at 5:56 | comment | added | Todd Wilcox | The tangent is pretty different from sine and cosine. It's sort of one step removed from the fundamentals of trigonometry, whereas sine and cosine are right there at the foundation. We talk about tangent a lot in high school because it makes analyzing triangles easier. The analysis of periodic functions (what mathematicians would call most sound waves) relies heavily on Euler's formula, which uses complex numbers, sine, and cosine, but not tangent: en.wikipedia.org/wiki/Euler%27s_formula | |
| May 10, 2015 at 5:49 | comment | added | Todd Wilcox | Actually when a waveform is mathematically analyzed and broken down into its components (a process called Fourier analysis), both the sine and cosine are used. When you see or hear "sine wave", it really refers to either a sine or cosine wave, since they have the same shape and human ears can't hear the phase difference which is the only difference between sine and cosine. Maybe the animated graphic on the right side of this page will help with your overall question: en.wikipedia.org/wiki/Fourier_transform#Introduction | |
| May 10, 2015 at 3:58 | history | edited | user28 | CC BY-SA 3.0 |
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| May 10, 2015 at 3:56 | comment | added | user28 | The y-axis is amplitude. Pitch is based on the frequency (inverse of the wavelength), so given a fixed x-axis it would be indicated by how compressed the wave appears horizontally. Cosine is no different from sine, it just doesn't really make sense to "start" making sound at anything other than zero. You could generate sound based on a tangent, but going from infinitely loud to zero to infinitely loud again is both impossible and just noise. Basically I think all your questions are just based on a misunderstanding of what a waveform shows. | |
| May 10, 2015 at 2:06 | review | First posts | |||
| May 10, 2015 at 6:50 | |||||
| May 10, 2015 at 2:03 | history | asked | user108262 | CC BY-SA 3.0 |