Why isn't Slow Motion audio real?

[DankDoodles]

All slow motion sounds you hear from a slow motion video are sounds that they later add to the video, meaning you aren't actually hearing the real sound in slow motion but only something that might sound like it.

 

How come there isn't any slow motion microphones yet?

Is it harder to make slow motion microphones than cameras?

Why is that? etc

Haven't found any reason or news about slow motion microphones

[.Apex.]

1 minute ago, DankDoodles said:

All slow motion sounds you hear from a slow motion video are sounds that they later add to the video, meaning you aren't actually hearing the real sound in slow motion but only something that might sound like it.

 

How come there isn't any slow motion microphones yet?

Because slowing down audio would slow down the frequency and therefor you'd only be listening to a few Hz rumble which isn't discernible and you'd probably not be able to hear it anyway as humans cannot hear below 20Hz

[.Apex.]

13 minutes ago, DankDoodles said:

How come there isn't any slow motion microphones yet?

You don't need a special Microphone for that, you can do it on any audio clip as long as the sample rate is enough to make a coherent sine wave once slowed down to your requirements

[tkitch]

take any normal sounds (Vocals, Effects, whatever) and slow it down to 1/10th speed in any audio app.  (Audacity should do just fine.)

That'll be why.

[DankDoodles]

12 minutes ago, tkitch said:

take any normal sounds (Vocals, Effects, whatever) and slow it down to 1/10th speed in any audio app.  (Audacity should do just fine.)

That'll be why.

Is it too hard to record it in a higher frequency so it can sync with the slow motion camera?

[tkitch]

The audio is sync'd.

Audio and video don't work the same way.  Audio sounds really strange when slowed down.  There is no 'high fps audio' to counteract that.

[emosun]

21 minutes ago, DankDoodles said:

How come there isn't any slow motion microphones yet?

light travel faster than sound , a slow motion sound wave is so incredibly slow that theres nothing to hear at that slow if a frequency.

slow motion bullets..... are literally 2 to 3 times the speed of sound. 

[emosun]

3 minutes ago, DankDoodles said:

Is it too hard to record it in a higher frequency so it can sync with the slow motion camera?

the frquency of the vibrations in the air that make up audio are too slow to create sound , look at slow motion speakers to see how slow sound waves really are.

[SupaKomputa]

audio doesn't run like moving pictures, ie using frames per second.

the recording device will capture anything, so slowing it down is what you will hear in real time. 

[tkitch]

for a more real-life example of this, check this out:
 

 

The Doppler effect helps explain this.  If something doing /only/ 30 MPH will change how sounds are heard?  Changing with high-speed video will SERIOUSLY mess with it.

[LogicalDrm]

-> Moved to Videography and Photography

[sub68]

On 10/10/2020 at 8:25 PM, DankDoodles said:

How come there isn't any slow motion microphones yet?

thats a normal mic

that audio is slowed down to the same amount as video

 

[Jozhua]

Using a higher sample rate like 96KHz will help with doing "slow motion audio". Certain NLE's and DAW's will preserve audio pitch when speeding up or slowing down an audio sample, so it's certainly very possible.

In regards to "slow motion microphones", it depends what you mean. The different pitches of sound we perceive are created by different frequencies of audio waves, so inherently you will always pick up any audio waves generated between 20Hz-20,000Hz, provided you are sampling at double this rate (Nyquist Theorem!) If you mean picking up sounds above 20,000Hz, then yes, there probably is an application for a kind of "slow motion microphone". You'd need something with a smaller diaphragm which is more responsive to these kinds of frequencies. In fact, in general audio recording, different microphones are selected depending on what kind of frequency audio you might want to pick up.

For the most part though, it probably doesn't sound like the audience will expect, so most slow motion videos will use foley and sound effects to create a soundscape after the fact.

[theonly500]

What Jozuha Said. Imagine the highest pitched squeal you could think of. Like a squeaking brake. If you would look at that in slowmotion you would see it vibrating. And each movement back and forth is one wave you would hear.
 

So if you're able to see the movement clearly you can't hear it.
Imagine this. You would film a speaker, even though you can see it vibrating, you can't make out the individual movements, you can feel them as vibration of the diaphragm, but you can't make them out either. If you were to slow that movement down, to a point, where you could see the individual movement, you could feel it, but can't hear it anymore, that is because the speaker now runs to slow for your ear to pick it up. And the same goes for slowmo. Imagine you could actually slow something down from a point where it would make sound, to a point where you could see it. It would be as audible, as your speaker moving at that speed.

And there are "slowmotion" Mics already. They are used in studies of animals, which comunicate with HF Audio above 20kHz. Although they don't slow down like video. Because it works on a different principle than Light.
 

[OscarMike]

have you never slowed or sped up a video in youtube?

[DankDoodles]

On 12/3/2020 at 10:19 PM, OscarMike said:

have you never slowed or sped up a video in youtube?

Nope

[OscarMike]

10 hours ago, DankDoodles said:

Nope

next time you watch a youtube video click the cog where you change the resolution. click play back speed. and you can change it there. it simply slows the video or speeds it up without changing the pitch of the audio