Lovely question! He's using a different definition of the decibel that is more common in audio. If you'll consider wikipedia:Decibel, there's a nice table that relates decibels to power ratio in a general way that applies here. 0 dB means his speakers are getting a full power ratio of 1. -infinity dB, although not shown, means that his speakers will get no power. Also, up or down from his zero level is equivalent. It's like stretching or compressing a spring. Hope that helps.
Wonderful, once again! I'm cramming for a Year 12 physics extended investigation I have due in two hours, aaand I didn't listen in class. So I'm making up for it!
I have several problems with the explanation given in this video for how sound works...which, unfortunately is the "official" version as taught in the school science curriculum. To zero in on one: @6:16 you state that sound is a vibration of air particles (with air as the propagating medum) and you suggest, with your pen, that they are vibrating in a longitudinal manner (changing position to be alternating closer and farther from the eardrum which they are near). So, I guess these air particles are imparting that vibration to the eardrum? What force(s) are acting on the particles to make them move toward the eardrum? And, perhaps more important, what force(s) make them move away from the eardrum? When the particles are moving away from the eardrum, how do they...pull(?) on the eardrum to make it move? To make it flex toward the sound source. In this video (czcams.com/video/cK2-6cgqgYA/video.htmlm55s), it seems to be working exactly as you describe it with the air particles "vibrating" (moving back and forth near the diaphragm), pushing and pulling on the diaphragm, making it move by some sort of sympathetic action. But, just as in your video, no explanation is even attempted to explain the forces acting on the air particles to make them vibrate nor is there any explanation of the forces acting on the diaphragm/eardrum to make either of them move. I would be interested (as I'm sure would others) to know just what is making those things move as they are shown to do (at least as can be hand-drawn or animated) and more importantly, how it actually works when sounds are present. salaphysics 070419
Super thanks. You made it so easy to understand. I needed to understand sound and it's measurement for doing statistics on noise levels. This certainly helps and corrects the wrong I was doing.
I'm a firm believer that "real" stuff takes precedence over mathematically derived stuff. BNSF rails pass by my house and just over a mile at the closest. I can clearly hear the horn on the locomotive. I can not just hear it, I can record it (analog or digital) and get a playback that's about as loud as I heard it. I know there is nothing in the recorder that has any logarithmic characteristics. Thoughts? On a related side note, why don't the compressions and rarefactions of the longitudinal sound waves diffuse in the 5+ seconds it takes for the sound to reach me?
Thank you very much. Just two questions: (1) if a jet Aircraft is climbing and passing over a little town and is about 3000 ft of height, is going to be an Issue for people? That place also has mountains and is at 11000 ft of elevation. For me is not an issue. (2) have you hear about LabView? If so, what do you think about of use it for sound spectra analysis?
0.00dB is a neutral level. Sounds like the sound was travelling in a panning effect while maintaining a neutral sound level. Someone correct me if I'm wrong.
@ about 3:45 to 4:00 You ask if we would "agree". I do not agree. If we try to follow your mathematically derived explanation, we're forced to conclude that, like the eardrum, a (dynamic) microphone diaphragm must also give a usable output when it moves only the width of a molecule. See my previous post that was ignored/overlooked/too-wrong-for-consideration. We need a better description of how sound propagates than is taught in the school science curriculum.
in school we learnt that the lowest frequency we hear is 20hz.what's the relation between 20hz and 10 ^_12.and when intensity depends on r,why there is no r in I=2p(rho)π^2a^2f^2v
no relation you can have sound signal with 120 dB having frequency 20 Hz.... frequency and loudness are two completely different and independent things...
sorry continued here....if he goes back down to -INFdB and then carrys on down how can it be getting louder if silence is in the middle and loud is up then down should just be nothing like turning a volume knob.I hope you can help because i really need to understand this before i move on.
I wonder if you can answer a question about decibels i have on someone elses video explanation that i dont get.If you type in decibel to u tube at the very top is an example by war beats for audio.He shows a wave and says the middle is -INFdB 0.00 then goes up from it too -0.00db and then back to the centre -INFdB 0.00 and then down to - 0.00dB.So far i learned that - INFdb 0.00 is no sound.So i can understand how going up from that to 0.00db reaches maximum for computer...but continued
+david cano Yes. You can calculate the 90th percentile of any data range, including a range of leq readings. Note the acoustic term "L90" is actually the mathematical 10th percentile. Excel has an easy percentile function you can look up.
It's for sake of calculations... it is easy to calculate when it comes in power of 10.... most of sound level we write are like -10dB, 30dB, 60dB, etc..... so it'd been very difficult to write it down in natural log(ln function on any scientific calculator) system...
I understood that far more than anything my lecturer ever said. Why I only finding this now when my exams tomorrow? :(
Two years later here I am at 1 am and my exam is tomorrow morning.
HAHAHAHAHAHAH FUCKING RELATABLE AF. 2 YEARS AGO THO. U PROBS GRADUATED
My exam is 4 more hour from now😂😂 im so worried that i will fail this exam rip
FarFarAway
What happened? Did you fail?
@@Namajaff thank god, i got B for physics haha i guess i was lucky that the exam questions were not too complicated😆
Says "Vibration" 06:17 - the marker in the left starts oscillating.
Lecture level: Jedi
I miss these lesson in the class and I just saw these video and everything is clear now! Thank you 😊
You are one of the best teachers in physics as far as I have seen
This video helped me a lot
Lovely question! He's using a different definition of the decibel that is more common in audio. If you'll consider wikipedia:Decibel, there's a nice table that relates decibels to power ratio in a general way that applies here. 0 dB means his speakers are getting a full power ratio of 1. -infinity dB, although not shown, means that his speakers will get no power. Also, up or down from his zero level is equivalent. It's like stretching or compressing a spring. Hope that helps.
Wonderful, once again! I'm cramming for a Year 12 physics extended investigation I have due in two hours, aaand I didn't listen in class. So I'm making up for it!
happy physics man is happy, thank you.
Great video! I missed this lecture in my physics class, and this really cleared things up for me!
YAY!
What kind of energy is it that you mentioned and how can I calculate it?
wow best teacher EVER ! wow.
I have several problems with the explanation given in this video for how sound works...which, unfortunately is the "official" version as taught in the school science curriculum.
To zero in on one:
@6:16 you state that sound is a vibration of air particles (with air as the propagating medum) and you suggest, with your pen, that they are vibrating in a longitudinal manner (changing position to be alternating closer and farther from the eardrum which they are near). So, I guess these air particles are imparting that vibration to the eardrum?
What force(s) are acting on the particles to make them move toward the eardrum? And, perhaps more important, what force(s) make them move away from the eardrum?
When the particles are moving away from the eardrum, how do they...pull(?) on the eardrum to make it move? To make it flex toward the sound source.
In this video (czcams.com/video/cK2-6cgqgYA/video.htmlm55s), it seems to be working exactly as you describe it with the air particles "vibrating" (moving back and forth near the diaphragm), pushing and pulling on the diaphragm, making it move by some sort of sympathetic action.
But, just as in your video, no explanation is even attempted to explain the forces acting on the air particles to make them vibrate nor is there any explanation of the forces acting on the diaphragm/eardrum to make either of them move.
I would be interested (as I'm sure would others) to know just what is making those things move as they are shown to do (at least as can be hand-drawn or animated) and more importantly, how it actually works when sounds are present.
salaphysics
070419
I think these are relative measurements for specific applications, not the physics definition I'm using here.
The amount of energy that a sound wave carries in one second
"I stuff breaks"!! Lol. This guy's hilarious
I used to HATE physics and now I watched this and you just made me love it and interested in anything that you say
AnimeFriendship
FUCK OFF then
This really vibrates my eardrums.
It's log 10 so that you can give them in objective questions in which ratio is some power of 10
For instance, in my favorite audio editor, 0dB means that I'm not changing the amplitude of the signal. So it's neutral in that sense.
Super thanks. You made it so easy to understand. I needed to understand sound and it's measurement for doing statistics on noise levels. This certainly helps and corrects the wrong I was doing.
it helped a little and i like the spring analogy.I will look at that wiki link too :)
But if we perceive noises as decibels what is the “volume” we put up and down in our tv or cell phone?
I'm a firm believer that "real" stuff takes precedence over mathematically derived stuff.
BNSF rails pass by my house and just over a mile at the closest. I can clearly hear the horn on the locomotive. I can not just hear it, I can record it (analog or digital) and get a playback that's about as loud as I heard it.
I know there is nothing in the recorder that has any logarithmic characteristics.
Thoughts?
On a related side note, why don't the compressions and rarefactions of the longitudinal sound waves diffuse in the 5+ seconds it takes for the sound to reach me?
lol that intro xD
Your'e the best! i will be an engineer after thsi Board Exam!
Thank you very much. Just two questions: (1) if a jet Aircraft is climbing and passing over a little town and is about 3000 ft of height, is going to be an Issue for people? That place also has mountains and is at 11000 ft of elevation. For me is not an issue. (2) have you hear about LabView? If so, what do you think about of use it for sound spectra analysis?
Can we hear temperature
Nice video. Please make a video for Noise Weighting
0.00dB is a neutral level. Sounds like the sound was travelling in a panning effect while maintaining a neutral sound level. Someone correct me if I'm wrong.
very clear!!! like your video very much!!! love u!
Can we then absorb intensity of sound to create concentrated energy
Good Explained!
But whats difference between SPL and SIL and when we talk about Sound Level we are talking abot SPL or SIL or both?
Helpful yet concise. Thank you.
Best teacher ever🤗🤗
love your enthusiasm my friend :)
@ about 3:45 to 4:00 You ask if we would "agree". I do not agree. If we try to follow your mathematically derived explanation, we're forced to conclude that, like the eardrum, a (dynamic) microphone diaphragm must also give a usable output when it moves only the width of a molecule. See my previous post that was ignored/overlooked/too-wrong-for-consideration. We need a better description of how sound propagates than is taught in the school science curriculum.
in school we learnt that the lowest frequency we hear is 20hz.what's the relation between 20hz and 10 ^_12.and when intensity depends on r,why there is no r in I=2p(rho)π^2a^2f^2v
no relation you can have sound signal with 120 dB having frequency 20 Hz.... frequency and loudness are two completely different and independent things...
how do you get radius what distance are you measuring? from you to the mic?
sorry continued here....if he goes back down to -INFdB and then carrys on down how can it be getting louder if silence is in the middle and loud is up then down should just be nothing like turning a volume knob.I hope you can help because i really need to understand this before i move on.
I wonder if you can answer a question about decibels i have on someone elses video explanation that i dont get.If you type in decibel to u tube at the very top is an example by war beats for audio.He shows a wave and says the middle is -INFdB 0.00 then goes up from it too -0.00db and then back to the centre -INFdB 0.00 and then down to - 0.00dB.So far i learned that - INFdb 0.00 is no sound.So i can understand how going up from that to 0.00db reaches maximum for computer...but continued
hahaha funny guy and great explanation!
thank you sooo much, now I actually understand!
Good geometric explanation
Crayola!!!
Thanks!! This is really helpful
شكراً ... thanks
GREAT EXPLAINATION..
if we are looking for the Power?
+Keven Cantoral The Power of Castle Grayskull?
or is it +15.00 dB that's neutral...I can't remember now.
Cool!. I finally understood!!!
thank you very much, great explanation. (y)
is it only me or beta looks like hearts sometimes
Hi Doc, is it possible to calculate a 90 percentil from a set of leq readings?
+david cano
Yes. You can calculate the 90th percentile of any data range, including a range of leq readings. Note the acoustic term "L90" is actually the mathematical 10th percentile. Excel has an easy percentile function you can look up.
sorry actually his is the 6th video down if you type into u tube decibels it will have mastering decibels war beats tutorial.
Why is it frustrating to use log base10? Im being curious :)
+Santiago Bañuelos It's just unnatural. A silly consequence of having five fingers on each hand. My father was killed by a six-fingered man.
It's for sake of calculations... it is easy to calculate when it comes in power of 10.... most of sound level we write are like -10dB, 30dB, 60dB, etc..... so it'd been very difficult to write it down in natural log(ln function on any scientific calculator) system...
nice lecture very helpful
Why do you think ln is better than log?
It's like bare feet in the summer!
Great 💖
sir, can u help me with concepts of electric potential.... these videos are great help... thank you
photon n That is a very tricky topic. I have made a few videos on it - I hope they help.
ok thnx sir... i'll browse it
LOL camping is intense too
thanks!
Intensity is basic or derived?
Guys I'm Gonna Die I Need YOu Help I Have Ass Cancer
haha camping in tent city
Got it. Easy as pi. ;-)
Maybe 4pi...
Did you missed primary education ?
Chiii 😖
R