Hi eveyone. I've only just gotten around to flying my p4 around at 30m mark in my local park as getting used to the controls.  Just out of interest what is the minimum virtitcal height to be maintained whereby the sound coming from the drone becomes barely audiable?

It's not that simple.
Wind/calm conditions can make a big difference to what is heard on the ground.

Labroides Posted at 2018-4-1 12:55
It's not that simple.
Wind/calm conditions can make a big difference to what is heard on the ground.

The council worker's use battery and  petrol leaf blowers and I've heard the sound of them travel over 1 mile away. They are much louder than a p4.

P4's are notoriously loud.  A barely audible sound straight up from your location would have to be over 300 ft probably.

Well max legal altitude is 120 mtrs i can easily hear mine at that height

Hello depends on the wind many times at the maximum height of flight in a straight line upwards sometimes not heard (120 mts)

We do not have the minimum height of audible drone sound. Sorry about this. It would be better to practice in an open place for the first several times.

ALABAMA Posted at 2018-4-1 13:47
P4's are notoriously loud.  A barely audible sound straight up from your location would have to be over 300 ft probably.

I love the sound of a Phantom !!!
It makes me realize the app and telemetry was working perfectly and I made it back.......lol

I can easily hear my p4p at 120m high and thats whilst windy, i can also easily hear it at 3-500m out (wind dependent) so no chance going incognito at the park there are times when i would have preferred the Mavic Pro and sound is one of those, but i opted for the more professional looking and superior camera, extra noise is a payoff, but when your mates comes out with his Mavic, only then you realise how LOUD your P4P really is

Sound travels with the wind. sound is a funny thing  because its not a physical thing you can touch that is made from material like a plastic bag or a kite or drone and tress but sound its not physical. Its indivisible so how can the wind grab something invisible and push it along as is its made of material.  Going back to decades ago. As a kid I used to play around on a hillside in an 700ft elervated position from ground level below. I always remember watching a group of people playing a game of  cricket around half mile away below in the valley. There was a light breeze coming up to the hillside from there position which carried there converstion in parts past my ear. Sound is weired because it acts like its actually made from somthing but its  not physical.  I can never understand how that works out.

It would be nice if DJI would develop some quieter props for the Phantom series.  I would sacrifice a little performance for the ability to be stealthy.

djiuser_zUQ9JbysumUX Posted at 2018-4-2 04:59
Sound travels with the wind. sound is a funny thing  because its not a physical thing you can touch that is made from material like a plastic bag or a kite or drone and tress but sound its not physical. Its indivisible so how can the wind grab something invisible and push it along as is its made of material.  Going back to decades ago. As a kid I used to play around on a hillside in an 700ft elervated position from ground level below. I always remember watching a group of people playing a game of  cricket around half mile away below in the valley. There was a light breeze coming up to the hillside from there position which carried there converstion in parts past my ear. Sound is weired because it acts like its actually made from somthing but its  not physical.  I can never understand how that works out.

Uh in many ways sound is a 'something' as it depends on the particles in the air or ground or whatever for those waves to travel along...very similar to how a wave in the ocean works.  Air is nothing more than a combination of particles and elements, which can include water, dirt, etc.
Sound travels based on many factors, almost too many to list, but depending on air density, temperature, wind, amount of particulates (i.e. rain, dust) will all help determine how well the sound travels and even how fast it will travel.  Also, the area you are standing in as it relates to the sound and the direction the sound is coming from can effect your ability to hear it.
For example, some rooms allow a person's whisper to travel to the far side of it where another can hear it as if they were standing next to the person whispering, because of the acoustics of the room.  The same thing can occur if you were standing inside a rock quarry with the drone above you, the sound would echo off the walls and collect in certain areas of the quarry based on the size and distance from the walls i.e. amphitheaters and how they effect sound direction and levels
To try and explain it further is going to make this very technical, and more than I'd prefer to get in to.  I'm sure some can weigh in if they prefer and have the will to dive deep on the subject.