P3 Audio, Lets Think About Audio Solutions

[TonG]

What makes you so sure?
Come on, tell us why it's impossible.

I can see a quiet and invisible drone in the future.

Making it inaudible is almost as difficult as making it invisible!!!

Its hard to explain why not if you don't have a thorough knowledge of the principles of sound.

Sound cancelation is less difficult when you have a simple sound source. that means only a few frequencies with and a more or less predictable time pattern.
Alas; the noise of the 4 props is a very, very complicated sound source and it is changing irregular al the time!

You need lots of microphones to pickup this sound and a very big number of little loudspeakers, amplifiers, computing power to produce the antisound (180degrees phase shift for every momentary frequency there is. And there are thousands and thousands of them.) You almost have to built the P3 into a tight case of microphones an loudspeakers.

And this is only a tiny little bit of a very long and complex story. The theoretical principle is very simple, the practical application in a real world is very complicated.

 

[PishPosh]

You need lots of microphones to pickup this sound and a very big number of little loudspeakers, amplifiers, computing power to produce the antisound (180degrees phase shift for every momentary frequency there is. And there are thousands and thousands of them.) You almost have to built the P3 into a tight case of microphones an loudspeakers.

Or you can wear ear plugs

In all honesty though, even IF a silent copter is possible, you still wouldn't get very good audio with an on-board mic. The subject is usually pretty far from the camera when filming aerials. The best thing, I think, would be to record audio separately on the ground, on or near the area you are filming.

 

[TonG]

Or you can wear ear plugs

In all honesty though, even IF a silent copter is possible, you still wouldn't get very good audio with an on-board mic. The subject is usually pretty far from the camera when filming aerials. The best thing, I think, would be to record audio separately on the ground, on or near the area you are filming.

Recording (location)sound is a very underestimated practice.
The best remedy against it is: try it and you will see, sorry hear, how difficult it will be.

And it has much more to do with the qualities and knowledge of the recording person then the qualities of the microphone(s).
Off course if you want to pickup a distant sound source a highly directional mike wil do a better job than a omnidirectional mike. But it is only a part of the story.

And remember if you are out there your ears are constantly fooling you. You will hear the truth as soon as you play your recording on a speaker.

 

[PishPosh]

Recording (location)sound is a very underestimated practice.
The best remedy against it is: try it and you will see, sorry hear, how difficult it will be.

And it has much more to do with the qualities and knowledge of the recording person then the qualities of the microphone(s).
Off course if you want to pickup a distant sound source a highly directional mike wil do a better job than a omnidirectional mike. But it is only a part of the story.

And remember if you are out there your ears are constantly fooling you. You will hear the truth as soon as you play your recording on a speaker.

I don't think it's very complicated or difficult at all. Recording a jazz band in the studio is much more complicated than this.

Chances are, if you're filming aerials, you're looking for ambient sounds. That's easily done with a stereo mic, or a pair of mics in whatever stereo array you like. You could even do them separately, like record some ambient audio first, and then fly the drone for video. If you're filming the surf, then something directional, like a shotgun pointed toward the ocean, might be more useful. If there is a subject that is talking, and you want that audio, then a wireless lapel would work.

If that is too technical or expensive, just using your smartphone voice recorder app is still infinitely better than an on-board mic or no audio at all.

Check your meters, make sure it's armed and recording, and do a sync clap before lifting off (if you want/need to synchronize the audio with the video in post).

And if your ears keep fooling you, like what you hear on site is that much different from what you hear in the studio, then chances are you haven't been monitoring your audio while on site, and/or your gear is not up to par for your standards.

 

[Fyod]

Rode wireless mics that record to their own SD.
Record the sound on the ground (skateboarding), mounted to the controller for example. Then sync with the video.

 

[TonG]

I don't think it's very complicated or difficult at all. Recording a jazz band in the studio is much more complicated than this.

Chances are, if you're filming aerials, you're looking for ambient sounds. That's easily done with a stereo mic, or a pair of mics in whatever stereo array you like. You could even do them separately, like record some ambient audio first, and then fly the drone for video. If you're filming the surf, then something directional, like a shotgun pointed toward the ocean, might be more useful. If there is a subject that is talking, and you want that audio, then a wireless lapel would work.

If that is too technical or expensive, just using your smartphone voice recorder app is still infinitely better than an on-board mic or no audio at all.

Check your meters, make sure it's armed and recording, and do a sync clap before lifting off (if you want/need to synchronize the audio with the video in post).

And if your ears keep fooling you, like what you hear on site is that much different from what you hear in the studio, then chances are you haven't been monitoring your audio while on site, and/or your gear is not up to par for your standards.

I can only fully agree with your arguments while mine arguments still holds true. It all depends on what you want to record and what quality you are striving for.

Let me take your own example: recording a jazzband in a studio with a multi mike setup is for various reasons a difficult task, because you want to have a high quality endproduct.
If you want to have that same quality final soundproduct/track when you are filming a small documentary it can be as difficult as recording a jazzband. To take all the different sound sources in a pleasant natural harmony and order without all kinds of disturbing ambient sounds is quit a job to do.

If you are only looking for some simple ambient recordings and do not care to much about high quality it indeed can be a simple uncomplicated proces.

Fooling ears: Our ear/brain combination is very good to hear only that sound we want to hear and reject or suppressing the unwanted sounds.
Recording quality sound begins with consciously listening to that sound and then try to act in accordance with your gear and wishes.
If you use a monitor setup on location then you are already active with good listening and won't be much surprised if you listening to your recordings afterwards.

 

[KillerCut]

Dont most new phones block out the background noise? Why don't they use similar technology to block out the sound of the props?

 

[Fyod]

So do directional mics.
But it would ideally have to hang a foot under the Phantom, you'd still hear wind gusts, they cost a couple hundred bucks and weigh a couple hundred grams due to the battery etc.
Generally just not a good idea.
Record the ambient sound from the ground and sync it.

 

[N017RW]

This is all but impossible in a 3D space. Noise cancellation must occur at the listener's location and requires the 'anti-noise' source be of the same frequency, amplitude, and exactly 180 deg. out of phase.

In the context of a quad buzzing around, you have multiple (infinte) listener's you can't cancel at all locations simultaneously due to the complexity of ambient conditions. Reflections, absorbtion, frequency and amplitude, etc. make the anti-noise signal different for each and every different location.

This is why the headphone tech. works because it is localized and actively cancelling for the noise at YOUR exact location. Essesntially treating the symptom (you) and not the cause (aircraft).

 

[sfpermits]

I saw a demonstration of active noise cancellation for a rotary lawnmower in the 1950s. I doubt this problem is more difficult, especially with today's level of electronics.

 

[N017RW]

The difficulty hasn't changed.

Where are these attenuated lawn mowers now?

 

[sfpermits]

This was in the 1950s. Probably, long, long, before you were born. But, it worked with 50s technology and, I would think, that today's electronics would be far superior. What I find odd is after scouring Google, I found nothing. So, I'm trying to revive the concept. After all, a silent drone would be a very interesting thing, nes pas?

 

[N017RW]

You make a lot of assumptions.
That's OK but perilous.

My post, #49, generally outlines the main issue.

It's a matter of physics not electronics.

 

[sfpermits]

There's a company Acousticontrol.com that specializes in dynamic noise cancellation in open office environments. So, an unenclosed sound source is not likely the problem.

I know I know no one wants to hear the buzzing of the drone not all the time at least.
This seems to be possible with GoPro mounted cameras as they obviously include audio but not
so much with the P2 Vision+ or P3, no audio.

This is great for certain captures, majestic stuff in the mountains in CO or say the Grand
Canyon. Edit and mix in your favorite music there really isn't the need to capture any audio
in shots like that.

But I can imagine use cases where audio would be very beneficial to capture conversations
or to get the full effect at sporting events etc. Audio would add context and emotion to video
capture.

How could this be done? I think maybe via wireless microphones paired up to the P3 so
that video and audio stay in sync. Range could be a concern but if you're getting somewhat
close action shots like this:

Being able to hear the skateboards would add a lot to the video i think.

Do solutions like this exist? When if ever do you think Dij would implement a solution like this?
They could sell the remote microphones as clip-on add-ons and would just need to work out the
technical details on how to get them synced up with the video being captured.