4dB is great on paper, but outdoors in the real-world it's hardly noticeable unless you have bionic ears, or you are flying in no wind and in the countryside with nobody around you. Which if you are, then who cares how loud it is?

Sharp Posted at 2017-12-2 04:39
4dB is great on paper, but outdoors in the real-world it's hardly noticeable unless you have bionic ears, or you are flying in no wind and in the countryside with nobody around you. Which if you are, then who cares how loud it is?

4 dB, in the 'bee-noise-frequency', the Spark is operating in, I am certain, that will be noticeable! Even for our ears! I can hear my 'bee' easily in 90m height and about 150m distance, on windless days

To be honest, I am happy with the noise level of my Spark. When you are busy with filming or taking pictures you inevitably have to also watch your screen from time to time or even frequently depending on what you are trying to achieve. The "sound of Spark" has often helped me to retrieve it quickly in the sky, especially in difficult lighting situations or when a bit further away. And the noise is low enough for not frightening uninvolved persons who are passing by.

Yeah, mark me down as wanting to be able to hear the tiny quad I’m flying.  It’s easy enough to lose this thing in the Sky.

Like the thought of noise reducing props for the Spark. Would like a fixed 3 prop design even more!

Not sure it's a great thing to have or not. When I felt not to disturb anyone, I keep it 50m away 30m up. Spark is so small I kept losing of sight 200m away when doing VLOS. But still having say that it will be awesome and stealthy

The quiet platinum mavic is interesting.  Might get one.  I doubt the spark is actually louder than the bigger propped drones.  It just makes noise at a higher frequency that is easily clearly heard and easy to find the direction off.  The Mavic sounds are more in the base range.  Quieter seems a good engineering path to head down so I can fly without bothering my neighbors or other people at a park.  The Spark already looks like a non threatening toy vs the Mavic and the Phantom.  A quiet Spark would be priceless.  Ducted fans?

Please make the props to make the Spark quieter! The people on hear asking why just don't understand. DJI is by no means satisfied with any of their products. The evolution of drones is never ending. Faster,stronger,quieter,more stable,better batteries, further distance, etc etc. Not in any particular order. The prop design change on the Mavic was one of the best moves DJI could make. The quieter these drones are the less annoyed or afraid others will be of them. With in the next five years almost every American will either own a drone or have flown one. Making them better in anyway is a good thing. So do us all a favor and don't ask "WHY WE SHOULD WANT TO MAKE BETTER DRONES" and instead talk about 'MAKING DRONES BETTER IN EVERY WAY".  

ImHereToCrash Posted at 2017-9-1 09:05
LOL what is wrong with your spark for it to be louder?  i can hear my mavic pro from 615 feet AGL and sometimes higher(no air traffic in the area i tested it at).. my sparks either that i owned sound dropped off around 150 feet AGL...

my mavic sounds like an angry hornet's nest from as far away as 1 and half blocks.. i couldn't hear my sparks that far..

LOL I'm not sure what you're hearing but the spark is definitely (IMO - obviously) way louder than my Mavic, that being said when I got the Mavic I never used the props it came with, I immediately installed the low noise props.

DronerX Posted at 2017-9-22 15:02
Winglets don't work on helicopters, etc. One of the best explanations I read is this -  Helicopter rotors do not have a constant AoA; in fact it wobbles constantly about its lateral axis as a wing. As the helicopter blade moves forward, the AoA of the blade decreases, and as it moves back, the AoA increases, so that lift is balanced for the advancing and retreating blade. Even as they do that, the "sweep" changes constantly  so that the rotor turns first faster than the blade advances and then slower than the blades retreats.

Winglets look cool and help a lot at a very certain flight regime and provide little benefit else-wise. They siphon energy off of the vortex and lean it "forward" a bit. It's kind of hard to explain without pictures, but suffice to say that a constantly changing AoA increases and then decreases the benefit of a winglet giving no net change, while probably increasing wetted area, blade momentum, and induced drag.

If you look purely at total wetted area, using the same winglet area and extend the wingspan of the prop equally would increase the lift and efficiency more than what as winglet is able to reduce drag to obtain the same lift and lift to drag ratio. Main reasons for implementing winglets is that when space is limited, winglets contribute to increased efficiency by reducing mostly drag, and not so much lift.

On a helicopter with cyclic / collective pitch, there is a continuous change in apparent wind direction (Angle of Attack) over the blades through a revolution. On most quadcopters today, especially those from DJI, there is no collective pitch. The pitch of the blades are fixed. The only angle of attack that occurs is through change in speed of the propellers. Higher speed of the props compared to surrounding air movement (such as during accelerations and deaccelerations) will cause a change in angle of attack.

So on a fixed pitch propeller, a form of winglets can work to reduce e.g. noise (drag) and increase efficiency. Winglets are thus feasible on a Spark. I would love to have a more quiet Spark. Isn’t the point to fly it inhouse, on familiy and friend events, making cool photos without disturbing / annoying others?

OAB Posted at 2017-12-25 01:18
If you look purely at total wetted area, using the same winglet area and extend the wingspan of the prop equally would increase the lift and efficiency more than what as winglet is able to reduce drag to obtain the same lift and lift to drag ratio. Main reasons for implementing winglets is that when space is limited, winglets contribute to increased efficiency by reducing mostly drag, and not so much lift.

On a helicopter with cyclic / collective pitch, there is a continuous change in apparent wind direction (Angle of Attack) over the blades through a revolution. On most quadcopters today, especially those from DJI, there is no collective pitch. The pitch of the blades are fixed. The only angle of attack that occurs is through change in speed of the propellers. Higher speed of the props compared to surrounding air movement (such as during accelerations and deaccelerations) will cause a change in angle of attack.

I'm glad you said this, I was about to say it. Two very different animals, quads and helps.

djiuser_AYC9sC7 Posted at 2017-12-30 19:06
I'm glad you said this, I was about to say it. Two very different animals, quads and helps.

A final remark on the upgraded props for the Mavic is also that the difference in the standard and new propellers are not just the swept tip of the propeller. The new Mavic Pro Plantinum propellers seems visually to have a significant higher surface area through longer profile chord from the root to the tip.

That means, if the propellers have the same lift to drag ratio, the RPM of the motors can be lower creating the same lift. Lower RPM of the motor and propeller will also reduce noise. That said, lower RPM for the same lift, also increases the torque on the motors.

It is a balance, but please make more efficient propellers. The propellers are after all one of the most important parts and functions on a drone when it comes to aerodynamics, performance and flight time.

ImHereToCrash Posted at 2017-8-31 23:09
compared to the mavic pro the spark is a whisper

Check this out:

Spark is 94dB
Mavic is 89.9dB
Mavic Platinum is 83dB

Being more than 10dB difference, the Spark is more than DOUBLE the volume of than the Mavic Platinum.

hackeron Posted at 2018-1-8 03:25
Check this out: https://www.youtube.com/watch?v=Gjs1QSa9fpI

Spark is 94dB

This thread is aging, but it’s worth noting you picked the *loudest* the Spark has ever done in a test to attempt to prove your point.

There must be 2 dozen videos showing the opposite that you must have noticed, so why post this one?

The Spark and Mavic Platinum are similar and the standard Mavic is 3-5db louder in test after test.  The Spark is *higher pitched* which is *subjectively* more annoying for some.  This makes sense considering the physics and is shown in basically every test *other* than the one you linked.

Only thing I'd care about is little better battery life with props, I did see a guy that was tinkering with little solar panels on the top of the drone to extend battery life, was pretty wild

I hope they make the newer props

DJI User724 Posted at 2018-5-5 23:31
Only thing I'd care about is little better battery life with props, I did see a guy that was tinkering with little solar panels on the top of the drone to extend battery life, was pretty wild

Solar on the sparks cover, where the GPS is under?
And in flight situations?
I for sure would , if I would see such prepared drone

Martin Lines Posted at 2017-9-1 03:56
Well 4dB is over a 50% reduction in actual sound pressure (3dB is 50%). However I read that there is a difference between actual level  and perceived and the perceived level of reduction is around 20%

Just so.  Excellent.

rarevfx4 Posted at 2017-8-31 23:28
This wouldn't make sense. #1 The new Mavic Propellers aren't even compatible with the Mavic Pro, means they use a different lock system. #2 These props reduce up to 4dB, which can be compared to a dead silent living room and you wispering in it. Not really noticable, since the spark is already quiet compared to its bigger brothers.

The human ear can detect changes in sound volume of 3 dB, which, if you're interested is a decrease in power by one half or an increase in power of times two.  You can totally hear a noise reduction of 4 dB.

There a a lot of confusion about the decibel (dB) unit of measure, Probably because some stereo equipment and sound measurement equipment use the term dB incorrectly.  Decibels are a relative measurement not an absolute measurement.  So you cannot correctly say the power of a particular sound is 4 dB, but you can correctly say that one sound is different (or has changed) by 4dB.

A similar unit is the dBm (decibel relative to one milliwatt), and this unit is an absolute measurement of the power of a sound.  This is what sound measurement tools (or your stereo, if it states the volume in "dB") actually mean when they indicate the volume in "dB".