What is Sound?
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- Опубликовано: 9 сен 2024
- How the Fourier Transform Works, Lecture 2 | What is Sound?
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Now we begin our journey into the actual maths of the Fourier Transform. Throughout the course, we'll be using sound to demonstrate one of the many uses of Fourier's theory, so in this lecture, we look at what sound actually is, how Fourier's theory applies to sound, and we even get to see a sound wave propagating through the air.
This is the fourth in this series of videos which take a new and visual look at the maths behind the magic of how the Fourier Transform works.
Please help me finish filming the course by supporting me on Patreon: www.patreon.com/MarkNewman
A transcript of this lecture can be downloaded from the following link:
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Thanks for watching the video How the Fourier Transform Works, Lecture 2 | What is Sound?
Excellent, excellent, excellent
Many thanks!
I really love your way in applying the formula right away in producing sound, which ofcourse means you've understood this formula very well! Thank you so much sir
You are doing a great job, I am a mathematician, I am making a research in representation theory and harmonical analysis and I have seen lots of books and videos on this subject, but you are one of the few who has helped me to really understand the interpretation behind the mathematics. You are blessed with the ability and the passion to explain this. Please, keep doing more videos, they are really inspiring to enter to this beautiful area of knowledge.
Thanks so much. Best of luck with your research. If it helps, today I published lecture #3 on phase: ruclips.net/video/n7hvhRdDg5g/видео.html
man this series has been so good so far. i get so used to the videos that just quickly show me how to do calculations and look up tables but i love how thorough this is without feeling like im sitting through a boring lecture
Thank you for your kind words. There is more to come. I am scripting further videos as we speak. Sorry the work is slow, they take ages to produce. However, it is a labor of love.
Underated stuff, this is brilliant content! Thank you Mark!
Great stuff! I’ve been looking for videos like this. You take the concepts that are usually in basic form and expand them to the next level without losing your audience. I’m a musician, composer and a scientist.
So interesting that you site "musician" amongst what you do. I too am a musician, which is one of the reasons the sound applications of Fourier's theories interest me so much. By the way, lecture #3 on phase is also online now: ruclips.net/video/n7hvhRdDg5g/видео.html. Interestingly, although our ears are very sensitive to amplitude and frequency, they are not so sensitive to phase as I explain, whilst sat by my piano in the video.
This is awsome! I am so pleased to have come across your videos. Thanks for imparting such valuable knowledge, for FREE! BIG UP!!
Thank you for this great video. The displacement of the ball is missleading though, because sound waves are density waves.
Mark, this is a truly phenomenal series of videos. Thank you for taking the time to create and share them with the world.
My pleasure. Please let me know if I can answer any questions or if there is anything else you are interested in me producing.
Thank you Mark, your channel is a gem.
Very thoughtful and well articulated explanation of wave and signal.
Ditto on on all the praise for this work Mark. I too, was an engineering student decades ago that struggled with this subject and I drop everything to watch the next episode. I just want to make sure (for my own sanity check) that at 6:06, while you are plotting change in amplitude, that you are simultaneously changing both the volume (amplitude) and frequency.
Yes... Indeed. I am changing both the amplitude and the frequency. Hopefully you can hear that in the audio too, but I've noticed on my laptop, for example, that its sound card has some sort of compressor in it making everything come out at the same volume... So depending on what you're listening to the video on, it might not be obvious. Glad you like the lectures. Lecture #3 is undergoing final editing as we speak and should be available by 21st June.
I wished we could learn this way back in my school time (long time ago). Thank you so much.
I don’t know how I should THANK you for this great content ❤
Please continue your lectures
Thank you for your kind words. New content out today. Check out: ruclips.net/video/tjYMprOD3GI/видео.html
Thank you so much sir
I really appreciate your efforts and I really hope there will be more informative videos like this
Awesome video! From an EE student at the Technion :)
One word "incredible"
for this explanation
Thanks a ton. The part where You add more and more frequencies and then vary amplitude to create music is mind blowing. The simplicity of nature completely revealed. All i need is now to understand the analysis we build upon this simplicity. I want to make a one time contribution but Patron allows only monthly. Please provide a link to Your youtube page where one could also make a one time contribution. Thanks again for this wonderful series.
Thank you for your kind words and your generosity. Take a look at the other videos on my channel and see if there is anything there that answers your questions. I have a whole series on Fourier Analysis. If not, please tell me what you like to know. I'm always on the lookout for new ideas for videos to make.
For a one time donation, please use the following link: paypal.me/MarkHNewmam. Many thanks.
Great video, thank you so much for making it!
My pleasure!
This is great and very well produced! Thank you!
You sir are a genius!, thank you so much!, you have some of the best videos I have ever seen, finally understanding the meaning behind such complex subjects often explained in the worst way possible.
This is how digital transmission theory was started. The Fourier Transform, and later the Fast Fourier Transform (FFT), was key in being able to process signals for transmission and reception. If only I'd known at the time how important that would eventually become....
I don't know if you've produced a video on Electro Magnetic Theory yet, Maxwell's Equations etc? It would be great to see your way of teaching the fundamentals and how mathematical functions like DIV, GRAD and CURL are used to explain and model all kinds of field patterns, from electro-magnetism to heat transfer and fluid mechanics. Uff, sorry, too much in one go! But some bite-sized chunks to explain the basics in a visual way would be great.
thank you so much sir , im so blessed to find ur videos . Now i can understand signals better than ever before and all thanks to you . please do uplode more of such amazing visualising videos on this subject . thanks a lot again.
So clear, thank you very much
Thank you very much! I am taking a Signals and Systems course and this does help me quite a lot, a great way of presenting this concepts.
I'm really glad it was helpful. I've just published the 2nd book in a series I have written on how the Fourier Transform works, using the same teaching style as in these videos. If you think these books could help you with your course, then please head over to howthefouriertransformworks.com/book-launch.html
Amazing
Excellent explanation sir.Please do more videos which would be helpful for many
I'm working on it as we speak. 3 new videos coming out towards the end of February and I'll shortly be announcing a chance to grab an early place on my new online course on how the Fourier Transform works.
Great job! We use same method in earthquake engineering to define waves to structures in frequency/period domain.
Wow. That is interesting. I never knew that.
Let’s say you have a record of a soundwave. If you plot the soundwave as a 3D graph, you can see the direction of the sound and the soundwave itself. Now, imagine that you have a 3D record of a soundwave. If you plot this as a 4D graph, the 4th axis would show the soundwave and the other 3 axes would show the direction of the sound. It’s fascinating to think about!
Great explaining and visualization
Thanks. Lecture 3 is now online too: ruclips.net/video/n7hvhRdDg5g/видео.html
I would have loved to have you as a lecturer at University. I want to hear your musical compositions! Are you a mathematician?
If he had been my professor at university, my career path might just look very differently!
Awesome work. Congratulations!
Thanks a lot!
Following this serie like it is Game Of Thrones. Next episode nooow! :)
You are making a truly amazing job. Keep it up!!!!
Thank you! Will certainly try. It just take AGES to make these videos. The 6 lectures I'm releasing at the moment were 3 years in the making. This is a hobby rather than my day job unfortunately.
@@MarkNewmanEducation All the hard work you put into this is truly amazing. Keep it up!
I enjoyed this! Thanx!😊
Great work
Thanks sir . I am from India.....this is the vedio I really want to see........
I'm so glad. Thank you.
Great Information..... ❤
clear explanation thanks
You are welcome
Thanks you .. Sos un crack!!! Salût
Excellent, very interesting
Glad you enjoyed it
This is suuuuuper cool!
keep in mind the blue bouncing ball buffeted by the sound wave wobbles towards and away from the sound source ( longitudinal wave ) as opposed to a water wave which is a transverse wave
Yes, I had a little trouble with that animation. In retrospect, the Schlieren image should have been rotated by 90 degrees around the Y-Axis. The idea was that if you think of waves in the sea, the ball would bob up and down on the surface of the water. My problem was I only had a 2-D animation of the sound waves not a 3-D one. Your point is totally valid.
Great work!
Thank you
It would be great your work on standing waves.
Great suggestion! Maybe after I finish working on the Fourier Transform course.
Such a great video. Although, I do apologize as I had to play it at 1.25x speed.
Thank you. Whatever works for you. That's the beauty of RUclips. For those who I speak too fast, they can slow me down, and for people like you, you can speed me up. Great feature. Well done RUclips.
Great job 👍
Thank you! Cheers!
This is beautiful
Brilliant!!!
Thank you
5:55 sounds like a siren
beautiful
I am v sure they make the Sheldon character from this man ( a compliment ✌️💐)
but how does the amplitude change as you change the frequency? at around 5:23, you were changing the frequency but the amplitude stayed the same; each cycle at the same height.
at around 5:28 you changed the amplitude but the frequency did not change. so how can you change the amplitude with respect to frequency at 5:58?
You can do whatever you want with the signal. The amplitude and frequency of the signal are completely independent of each other. You can change one without it affecting the other. I used an audio editor called Audacity to generate a sine wave and played with it so that I could demonstrate this. At 5:23 I wanted to show what the signal looks like as you change the frequency. At 5:28 I wanted to show what the signal looks like as you change the amplitude. At 5:58, we are no longer looking at the signal in the time domain, we are looking at it in the frequency domain. At 5:58 I'm changing the frequency only. The amplitude remains constant. Unfortunately, the graph bobs about a little as the software I was using to measure the signal and generate the graph isn't perfect. The height of the peak should be totally still. The peak should only be moving along the x-axis. In the frequency domain, the peak travels to the right along the x-axis as the frequency increases and returns to the left as the frequency decreases. At 6:05 I am changing both the amplitude and the frequency. The peak gets smaller as the amplitude decreases and travels to the right as the frequency increases. Then it grows again as the amplitude increases and moves back to the left as the frequency decreases.
I hope I understood your question correctly and have answered it satisfactorily.
@@MarkNewmanEducation
Oh thank you for the prompt reply, I guess my question wasn't very clear. I wanted to ask about the frequency domain. At 6:05, you were talking the amplitude getting larger and smaller so I thought you were only changing the amplitude, that's why i was thrown off by the wave moving right and left at the say time. I see now from your comment that you were changing both frequency and amplitude, so it makes sense now.
I have another question about the frequency domain. Given a single frequency sine wave, the amplitude goes from negative max to positive max, but in frequency domain,
it only shows the positive max. I'm assuming only the magnitude of the amplitude matters in this graph and you don't care about the direction because it's kind of accounted for by the frequency?
Amplitude is not directional. It is an amount of something, not where that something is going. As you cannot have a negative amount of loudness (the quietest a sound can be is no sound at all), the amplitude is always positive.
❤
It’s means that in pure vacuum there are no sounds?
Indeed. There is nothing to vibrate.
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Great video.
שבוע טוב
@@MarkNewmanEducation
To be honest I don’t understand. If there is something that vibrate in vacuum - there is something... any evidence about this theorem?
As far as I know, although I have never been there myself, space is soundless because it is a vacuum. Sound needs some medium to propagate through: gas, water, even solids, but in outer space where there is nothing, sound cannot propagate.
@@MarkNewmanEducation jajaja
No one knows the Vaccum. It’s just theory.
The exist can changed only to nothing. But the nothing is not exists... it’s relating to Zenon’s paradoxes. Like wave-particle duality that also related to this area of paradoxes. Kind of metaphysical arguments as far as I understand it.
sounds are perturbations in the ether.
awesome , but volume is too low , speak loudly