Drones are inherently noisy. The propellers move through the air quickly, causing vibrations and a significant amount of noise. As the propellers cut through the air in a circular motion, they often cut through the same bit of air resulting in a pitch being generated.
The DJI Air 2S noise is similar to a swarm of bees. The buzzing noise is much quieter than previous generations of DJI drones and is relatively quiet compared to other drones its size.
We talk about the drone’s noise in terms of pitch and volume. The pitch is how many waves of sound are generated per second, and the faster the blades spin, the higher the pitch. A few factors contribute to the drone’s noise, which we can discuss in the next section.
This audio file shows you what the DJI Air 2S noise profile is like when hovering:
What influences noise?
Manufacturers of drones try to minimise the noise the drones repeller is – that is very much down to the physics at play.
However, some things dictate the volume and qualities of the noise generated by a drone.
Size and weight of the drone
The drone’s size will dictate how fast the propellers have to spend to generate the thrust required for it to hover. Buying a heavier drone requires stronger motors and larger propellers to offset the increased weight and keep the drone in a stable flight.
Typically, larger drones will be louder, but DJI drone engineers have a few tricks up their sleeves.
The type of propeller
The propellers’ length, pitch and depth will also determine the quality of the sound generated. Larger propellers typically displace more air and therefore require fewer rotations per 2nd to keep the drone in the air.
The sound is also changed by the pitch and angle of the propeller.
A deeper and more angular propeller creates more sound in the air due to the amount of air it displaces as it moves.
There is a very sensitive balancing act between the sound of the drone and its flying efficiency. Flying efficiency will always take priority, as that keeps your drone safe.
How fast you are flying
Depending on how fast you are flying, you can influence the drone’s pitch.
The drone will sound higher pitched when accelerating in any direction. The higher pitch is because the propellers move much faster and cut through the air more times per second.
I have created the highest pitch when accelerating upwards as fast as possible with my drones.
The mode you are in
The DJI Air 2S comes in a few flying modes. Sport mode allows you to fly much faster and more aggressively. The volume of the drone will increase, and the pitch will also change dramatically as you are flying more aggressively.
Spooling up and down the motors quickly will create a varied tone and texture of sound.
The more aggressively you fly the higher the volume of the drone and the more varied the pitch will become.
Form factor
One of the main reasons drones make a high sound is that the propeller blades have to pass over the arms that hold them out beyond the drone’s body.
As the blades pass over the arms, it creates a temporary high-pressure system and low-frequency buzz. This low-frequency buzz is why we often hear a distance as the drone is flying. I.e. it is not one continuous and clean tone.
How loud is the DJI Air 2S?
Here are a few audio examples of the DJI Air 2S flying vs other Air generations.
DJI Air noise generated
Air 2 noise generated
Air 2S noise generated
You will notice that the original air has a much higher pitch sound than the next generation of DJI Air drones. That is because the air was a much smaller drone with smaller propellers.
People complained a lot about the noise of the original Air; therefore, the larger form factor and larger propellers have helped the new generations of Air 2S become quieter.
What does the Air 2S sound like?
The new generation of Air 2S sounds like a swarm of bees. However, the volume is much lower than the previous generation of DJI drones, making it perfect for when you need a low-noise drone.
The sound is not high-pitched enough to become annoying and will not be able to be heard at a distance of approximately 50 m.
How to make your DJI Air 2S quieter
Due to the physics of keeping a drone in the air, there is not much we can do to avoid the inevitable displacement of air causing the noise.
However, we have two approaches that can make your drone quieter.
- Absorb the sound – there are a few products on the market that can reduce the noise of a drone wallet hovering.
- Changing the propeller shape and morphology – you can change the propeller to minimise the amount of disturbance generated in the air whilst it is flying.
Silent propellers
You may buy various aftermarket propellers to ensure your drone operates as quietly as possible. Additionally, you can get propellers made of carbon fibre (which will protect your propeller should it come into contact with any overhanging branches).
By using different form factors and surface treatments, the noise of the propellers can be minimised.
These propellers have higher aerodynamic efficiency, resulting in lower noise, lower power consumption, and improved battery life for your DJI Air 2S.
People have noticed that the propellers produce a lower propeller whine because of the improved efficiency of cutting through the air.
You can also opt for carbon fibre propellers for enhanced stability and strength if you want stronger propellers.
Sand down the propeller surface
Frequently, when you purchase a drone from a reputable manufacturer, the propeller surface will have the manufacturer’s emblem raised or stamped.
For instance, one user on the DJI forum claimed that sanding the surface smooth with sandpaper, erasing the DJI logos, and cleaning up all the other moulding marks significantly reduced the noise produced.
The leading edge of my propellers can occasionally be chipped from flying or mistakenly flying into the high grass. If the irregularities are very small, I can sand them down to let the propeller’s leading-edge glide smoothly through the air. Otherwise, your only choice is to replace the propellers.
If you have purchased a drone widely used commercially, you may have noticed that the plastic has moulding marks on it from when the propeller was made. The leading edge should feel smooth and silky.
The trailing edge is the one that needs to be as crisp as feasible.
One of the greatest ways to fine-tune the design of your propeller is to use 800 or 600 sandpaper and fix the shape slowly by hand.
This grit leaves a slightly rough surface, but if you want to keep the sparkling appearance, you may polish them with finer grain sandpaper. Since the material is a reinforced nylon composite, damage is difficult to achieve.
If you are worried that it will affect balance, spend the same amount of time on each propeller and remove the same amount of material per propeller.
Passive noise reduction
Propeller shrouds for noise reduction and safety have been created by a business called Dotterel.
They lessen the noise produced by the intricate interactions between the drone’s body, arms, and blades.
A safety shroud initially absorbs sound from the propeller to lessen noise before reflecting any leftover sound up and away from persons on the ground below.
The core has certain frequencies that are absorbed since it is comprised of acoustic materials that do so.
Summary
In this article, we have covered all aspects of the DJI Air 2S noise-generating activities and compared it to previous generations of Air drones.
Even though there are a couple of ways to minimise the volume and quality of the noise generated by your drone, the only real way to change the sound of your drone is to purchase a lighter drone with a sound that you prefer.
