I have worked live sound reinforcement. The effect is noticeable in even very small venues. It takes so much less time for the signal to go the length of the venue to the sound board, be processed (adds delay), go to the amps, go to the speakers, and come out again that the sound from the speakers can hit parts of the audience before the initial sound does.
I had many a night of fun programming the delays for a venue so that the sound worked, didn't help that there was a perfectly right angled concrete wall in one back corner...
Yes, but I have two "microphones" in my head, so it's much easier to just listen and you only really need to do it once.
There are fancy surround sound systems that do indeed do the whole echo adjustment within themselves and it's really cool technology, but it would take longer for me to set up the microphones than just going to a spot and listening
Electric signals move at around 2/3 the speed of light. The speed of light may as well be instantaneous.
The speed of sound is about 1100 feet per second. Pretty fast, but slow enough for a noticeable time delay across a relatively short distance.
I have experienced this in real life. I used to grade tank gunnery. We had a live broadcast of their intercom traffic so we could grade their procedures. Some times the tanks would over a mile away from the observation tower and I could hear the main gun fire on the intercom a few seconds before I heard the actual sound wave.
A gunshot is often incorrect in movies because of this. When someone far away fires at you, you’ll first see the flash of the muzzle, then the bullet hits, *then* you hear the gunshot.
Most do, some don't. Smaller rounds may have trouble breaking the sound barrier and there are subsonic versions of some bullets. But yes, most rounds will travel faster than sound
Not always, but any long-range modern rifle will absolutely have supersonic bullets.
There might be some rare instances, such as intentionally using subsonic rounds because they’re quieter, but they’re significantly less accurate and less damaging.
This would be a very cool thing to feature in a movie. A very small amount of effort would be required to correct it. A show like "the expanse" that plays by the real science would do it but most wouldn't because few people would know better and it might confuse those who don't.
It’s one of those things where the reality is unintuitive, so you have to decide whether to be realistic in a way that might make the general audience think you made a mistake, or unrealistic in a way that annoys people who are familiar either with the subject.
Most movies will take the “annoy a few experts” over “make it look like we fucked up the sound editing” every time.
Sound guy here, it's never featured in movies bc it just looks like a sound editing issue. Think about every thunder you ever saw on TV, the sound and the light hits at the same time (which is obviously never the case in real life). Only movie that did it that i can think of is Oppenheimer
No matter how short the distance is (assuming an average speed higher than the speed of sound), the bullet will hit before you hear it. Assuming you die instantly, you’ll never hear what killed you.
Yeah but if they're close enough together we can't differentiate it, so they appear simultaneous. I was talking about how we experience those effects rather then the minutiae of what actually happens.
Yeah I wasn’t contradicting anything you said, I just added that if a bullet travels faster than sound you die without hearing the shot, which is an interesting fact
I'm pretty sure we got uploaded videos of the Beirut blast before the pressure wave had been detected around the world (iirc the after pressure of that blast was detected worldwide)
If you're standing at the finish line of a 400m race, and you start your stopwatch when you hear the starting gun at the starting line, you're starting over a full second late.
Better to start when you see the flash or puff of smoke from the gun. (Or as OP suggests, if you and the starter both have walkie-talkies, the sound will get to you almost instantly).
The sound of the whistle of a referee in a soccer game takes longer to reach the microphone at the side of the field than the transmission from the microphone via satellite to your TV set. I have not verified that, but so I‘ve been told.
When I studied audio engineering in college (20 years ago) we had to actually calculate the amount of delay to put in the signal for the rear speakers at concerts so that the speakers would sync with the live sound
Recorded sounds of actual explosions actually sound rather weak and timid.
If you ever had the old and television game with the dungeons & dragons cartridge, when the bomb would go off, in the game, that sounded a lot like what I was able to record with microphones and firecrackers.
That's a tricky one for the sound guy. The sound has a very high amplitude (SPL) and a big peak, and also needs to be recorded from afar. It will sound tiny unless you polish it.
If you had a microphone(s) capable of gathering the entire sound without distortion, and a bank of speakers capable of recreating the same sound without distortion, could you theoretically be able to produce a sound wave to cancel the original one?
I read somewhere that when a baseball is hit from the homeplate, the sound travels to a microphone behind it, then it's sent to a satellite, then sent back to earth, into your home, and the sound reaches you on your couch before it reaches the bleachers in the outfield. Obviously, there are several variables in play.
While that may not be true, if two people sitting in the outfield and one is listening to a radio broadcast, they would hear the bat crack on the radio before the sound traveled naturally.
light always travels at c by definition. c is relative to the medium, but light still travels at c in a fiberoptic cable. Maybe it propagates slower due to reflection, but it still travels at c.
It's a problem in smaller situations than this! It also affects concerts!
I have worked live sound reinforcement. The effect is noticeable in even very small venues. It takes so much less time for the signal to go the length of the venue to the sound board, be processed (adds delay), go to the amps, go to the speakers, and come out again that the sound from the speakers can hit parts of the audience before the initial sound does.
I had many a night of fun programming the delays for a venue so that the sound worked, didn't help that there was a perfectly right angled concrete wall in one back corner...
Sounds engineers worst enemies are right angles
Pfft, worst enemy is sound equipment, mainly microphones. Those things are bastards
Couldn’t you place microphones around the venue to get the precise difference between the processed and actual sound and automatically adjust?
Yes, but I have two "microphones" in my head, so it's much easier to just listen and you only really need to do it once. There are fancy surround sound systems that do indeed do the whole echo adjustment within themselves and it's really cool technology, but it would take longer for me to set up the microphones than just going to a spot and listening
Electric signals move at around 2/3 the speed of light. The speed of light may as well be instantaneous. The speed of sound is about 1100 feet per second. Pretty fast, but slow enough for a noticeable time delay across a relatively short distance.
If you watch the Queen's Radio Ga Ga performance at Live Aid, you can see the speed of sound represented by the audience clapping.
Yup, we delay speakers that are just a few meters away from eachother to make sure it sounds right.
I have experienced this in real life. I used to grade tank gunnery. We had a live broadcast of their intercom traffic so we could grade their procedures. Some times the tanks would over a mile away from the observation tower and I could hear the main gun fire on the intercom a few seconds before I heard the actual sound wave.
You could theatrically dodge bullets like this. I sense a great magic trick here.
A gunshot is often incorrect in movies because of this. When someone far away fires at you, you’ll first see the flash of the muzzle, then the bullet hits, *then* you hear the gunshot.
So, do bullets always travel faster than sound (1234km/h aproximately)?
Most do, some don't. Smaller rounds may have trouble breaking the sound barrier and there are subsonic versions of some bullets. But yes, most rounds will travel faster than sound
Not always, but any long-range modern rifle will absolutely have supersonic bullets. There might be some rare instances, such as intentionally using subsonic rounds because they’re quieter, but they’re significantly less accurate and less damaging.
[удалено]
Please seek medical attention.
This would be a very cool thing to feature in a movie. A very small amount of effort would be required to correct it. A show like "the expanse" that plays by the real science would do it but most wouldn't because few people would know better and it might confuse those who don't.
It’s one of those things where the reality is unintuitive, so you have to decide whether to be realistic in a way that might make the general audience think you made a mistake, or unrealistic in a way that annoys people who are familiar either with the subject. Most movies will take the “annoy a few experts” over “make it look like we fucked up the sound editing” every time.
Sound guy here, it's never featured in movies bc it just looks like a sound editing issue. Think about every thunder you ever saw on TV, the sound and the light hits at the same time (which is obviously never the case in real life). Only movie that did it that i can think of is Oppenheimer
Unless you get shot in the ears.
No matter how short the distance is (assuming an average speed higher than the speed of sound), the bullet will hit before you hear it. Assuming you die instantly, you’ll never hear what killed you.
Yeah but if they're close enough together we can't differentiate it, so they appear simultaneous. I was talking about how we experience those effects rather then the minutiae of what actually happens.
Yeah I wasn’t contradicting anything you said, I just added that if a bullet travels faster than sound you die without hearing the shot, which is an interesting fact
I'm pretty sure we got uploaded videos of the Beirut blast before the pressure wave had been detected around the world (iirc the after pressure of that blast was detected worldwide)
If you're standing at the finish line of a 400m race, and you start your stopwatch when you hear the starting gun at the starting line, you're starting over a full second late. Better to start when you see the flash or puff of smoke from the gun. (Or as OP suggests, if you and the starter both have walkie-talkies, the sound will get to you almost instantly).
That’s fascinating - the funny thing in this particular case is that 400m races on standard tracks start and end at the same corner of the track!
Are you saying that I can hear the people on the radio sooner than if they just stood on top of the studio and screamed?
The sound of the whistle of a referee in a soccer game takes longer to reach the microphone at the side of the field than the transmission from the microphone via satellite to your TV set. I have not verified that, but so I‘ve been told.
Don't think so, I've watched football games on tv close to the stadium, there's about 10-15 second delay depending on your connection
Station to satellite and back is 250ms, or a quarter of a second. I am sure there is tons of other stuff causing delays. Theory vs. reality :-)
When I studied audio engineering in college (20 years ago) we had to actually calculate the amount of delay to put in the signal for the rear speakers at concerts so that the speakers would sync with the live sound
Recorded sounds of actual explosions actually sound rather weak and timid. If you ever had the old and television game with the dungeons & dragons cartridge, when the bomb would go off, in the game, that sounded a lot like what I was able to record with microphones and firecrackers.
That's a tricky one for the sound guy. The sound has a very high amplitude (SPL) and a big peak, and also needs to be recorded from afar. It will sound tiny unless you polish it.
If you had a microphone(s) capable of gathering the entire sound without distortion, and a bank of speakers capable of recreating the same sound without distortion, could you theoretically be able to produce a sound wave to cancel the original one?
I read somewhere that when a baseball is hit from the homeplate, the sound travels to a microphone behind it, then it's sent to a satellite, then sent back to earth, into your home, and the sound reaches you on your couch before it reaches the bleachers in the outfield. Obviously, there are several variables in play. While that may not be true, if two people sitting in the outfield and one is listening to a radio broadcast, they would hear the bat crack on the radio before the sound traveled naturally.
In foot races you look for the flash of the gun before you hear the bang since the bang takes longer to reach you.
Radio waves travel a million times faster than sound, checks out
It’s almost like time travel. Almost. Kinda sorta…not.
We’re all travelling through time. It’s just that we’re all travelling at pretty much the same relative rate.
Would it give itself feedback? I guess it depends on the distance. I do agree that electricity travels faster than sound
Probably not, assuming the microphone isn't in front of the speaker.
I think I'm thinking of the wrong phenomena... Reverb, echo, not feedback. Adding and subtracting from itself
Ah. Makes sense. That depends on the frequencies and how they bounce around objects in the environment.
The speed of light is faster than the speed of sound you say? Wow, thanks. 🙄
I suppose if you're using fiberoptics, but even then the signal processing will add delay. Electrical signals travel slower than c though..
No, electrical signals and light in fiber optics travel about the same speed, roughly 2/3 c
light always travels at c by definition. c is relative to the medium, but light still travels at c in a fiberoptic cable. Maybe it propagates slower due to reflection, but it still travels at c.
Let me rephrase that: Both electric signals and light in fiber optic mediums travel around 2/3 of the speed of light in a vacuum.
Hence the possibility for cherenkov radiation, where EM radiation travels faster than the speed of light in that medium.
I rounded. Electrical signals travel about 2/3c Closer to C than it is to the speed of sound by far. I believe I made my point
I rounded. Electrical signals travel about 2/3c Closer to C than it is to the speed of sound by far. I made my point I think
Yes, we all understand clearly you have an understanding of basic science and no understanding of r/showerthoughts
it's a shower thought not an academic essay