Why Are Drones So Noisy? How Can I Make My Drone Quieter?

The first time I saw a drone live in action was at a friend’s house. Before that, I only saw YouTube videos about and I was happy to see one in action.

After starting the drone, my first impression was not what I was waiting for. I was surprised at how annoying and noisy that little quadcopter can be.

At this moment my first thought was:

Why are drones so noisy?

The noise generated by drones is coming from their propellers. The electric motors are emitting such a low noise that is not even notable. On the other hand, the shape, length, and speed of the blades are making a big difference between the noisiness of drones.

In this article, I would like to help you understand why even hobby drones can be so annoying.

How noisy the drones are?

Before finding out the noise level the average drone can make we have to figure out why are we even talking about this.

I think if those small aircraft would not be so loud, you won’t even read this article.

Based on the data of cdc.gov any sound under 70 Decibels is not causing any hearing damage. A normal conversation and even an air conditioner are taking place under this level.

Based on their data, any noise above 70 dB may start to damage your hearing after a longer period.

Source: Healthlinkbc

Unfortunately, even the quietest drones are very close to this level. Drones like Funksy 913 or the from DJI are very close or even above 70 dB.

For example, the popular DJI Mavic is generating 72 dB with the rotors. Of course, you won’t keep these devices only beside your ears. I think you don’t have to be afraid of the long-term harms of a drone’s noise.

Similar articles: How to keep drones off your property and possible injuries by drone blades

The majority of them are above 70 dB, which based on this data is also causing you to feel annoyed by it.

Why do drones make noise?

To understand why even these little aircraft can make so much noise we need to know how are they functioning.

Hobby drones are powered by electric motors. These without any propellers are very quiet, so the amount of noise they can generate is almost negligible.

The majority of noise you can hear is coming from the propellers.

But why?

Based on the research published by NASA, the noise produced by propellers has been a scientific interest for a long time.

The buzzing sound you can hear is generated by the blades are cutting through the air.

The amount of noise these propellers are generating depends on the number of blades and flow velocity through the propeller blades.

The fewer blades a propeller has the less noise they are generating. By lowering the speed of the blades, the amount of sound they are generating is also getting reduced.

The main role of these blades is to convert the energy gained from the motors into thrust and torque.

Unfortunately, even the present engineering knowledge is not advanced enough to succeed using 100% of the energy from these electric motors.

More expensive drones are equipped with better propellers which is allowing them to function with fairly less noise.

It’s almost an unsaid truth that the more noise you can hear from a drone, the less optimized the blades are.

Are drones always loud?

After becoming a new owner of a done, or having one around you, the noise it can generate can become more and more disturbing.

Some people are getting used to it. Treating them as a source of joy or fun can make you more tolerant of that buzzing sound.

But being this patient is not for everyone. If someone is flying a drone too many times in your area, you might ask: are drones always that loud?

Unfortunately, in almost every case the answer is yes. And as it seems, this won’t change too much in the near future. 

These drones are moving with the help of propellers. By converting energy and slicing through the air these blades will always make some noise.

So, if you are waiting for silent hobby drones, you might need to wait some years. The average drone is generating a noise between 70-80 decibels.

There is a slight difference between drones, which can be enough to support them.

But the rule of thumb is that the only way to keep a drone quiet is not keeping it near you. It sounds silly, but this is the ugly truth.

If you are in the open field this is easy because of two reasons:

• You can support more noise

• The further the drone is from you, the less sound you will hear (which is obvious, but had to mention)

Down below you can see a video of a guy who is testing the amount of noise you can hear depending on the distance between you and your aircraft.

If you are using a smaller device indoors, the amount of sound it can generate will be significantly more intense. This is why even hobby drones are harder to tolerate inside your home.

How can I make my drone quieter?

No matter how much fun you can have with your drone, after a time the amount of noise it can generate will put you in front of Google.

Searching for solutions to get it quieter is almost a guaranteed step for a drone owner.

Turning down the sound it generates is an easy step. The only thing you need to do is slowing the propellers down. It’s stupid but it’s true.

But with this come less power which means that your aircraft probably won’t even fly.

To really make some difference you need to use different propellers.

To reduce the noise, you need aerodynamic blades that are rotating slower. Less rotation means quieter functioning.

A lot of manufacturers are offering these propellers. They have the same weight, but they are thinner and longer in general. Both of these properties are making it possible to use them with lower RPM.

Of course, the situation is not so simple. With the quieter blades are coming some disadvantages too.

These blades are thinner, so they are more vulnerable too. Besides this, you can notice more vibration while recording with the camera. These can be corrected with a software on your PC.

How loud are small drones?

Depending on the area you want to use, you will experience different noise levels. A small but not so cheap hobby drone like the DJI Mavic Mini is generating 55-57 decibels in the open fields.

This level can be measured from a distance of 5 – 6 feet between you and the aircraft. I think in the majority of cases this is the closest you will ever stand to your hobby drone.

These small unmanned recreational aircraft are used mostly outdoors, this is the main reason why the danger of getting your hearing harmed is almost impossible.

If you are planning to use them more indoors, buying a quiet propeller might be a good solution.

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