I didnt even look to see what the rpms were, i am always just worried about my battery and signal meter. Since the blades are about 1/2 longer I imagine that they turn slower in all aspects of flight. When I used to fly airplanes the bigger props were always quieter than the smaller direct drive ones.
Got my Mavic Platinum props today! 2 Decibles Quieter!
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ac0j
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2db quieter is basically NO quieter. From my experience in audio systems, the difference between one click up or down on your volume represents a 3db increase. They say that is because the human ear cannot detect a 1DB change in volume level.
So this whole prop debate is just down to performance and battery run time for me.
So this whole prop debate is just down to performance and battery run time for me.
Absolutely, when I plan a Southern California trip I most definitely will check out the shop. Thanks for the heads up. I've got a few spots near San Diego that that are on the bucket list.
First I think Stunnajd112 was saying this “Shot” is on his bucket list.
Second it is absolutely a no fly zone, that is the landing pattern for Naval Air Station North Island... how do I know??? I have been working there for 21+ years active duty Military in Naval Aviation [emoji846]. I also own my own Aerial Imaging company and would love fly and here to get these shots but I constantly get denied with any waiver I submit.
Third I hope people are not flying here, all they are doing it making it difficult for people like me to run a business in Southern California. Yes it is a side job but I am hoping it becomes full time when I retire from the Navy.
To all happy and safe flying [emoji106]
And others report 4dB. And every single video you listen to demonstrates a difference in perceived volume, due to a change in dB or pitch or both, I wonder if you've pulled them up? Was it doctored, a bad mic, something else, or would you agree that despite your assumptions they are indeed quieter? I find it funny that every person that says "you won't hear a difference" does indeed know something, but has zero first hand experience with the actual item they are disregarding.
I was skeptical as well, but the videos are hard to ignore, and I now have 4 on the way. I guess I'll see..
The new props are in stock as of this moment (FYI anyone looking for them)
They are much quieter. It's a much lower pitch sound that's not so piercing.
skypros
Well-Known Member
I just ordered a set a half (6 total props).
I received the email that they (DJI) had limited quantities.... and luckily enough I was able to get in on it.
I received the email that they (DJI) had limited quantities.... and luckily enough I was able to get in on it.
What kind of equipment do you have? Most of the systems I've had adjust in 1db increments. My current main system adjusts in 0.5db increments. And who is "they"? Everything I've read suggests that 1db is generally considered the minimum level humans can perceive as a change. In fact, here is a listing of various studies done, listing their findings on the minimum detectable change by humans:
Code:
Study Authors Year Published Min. Detectable Fluctuation
Reisz 1928 ~1 dB
Dimmick & Olson 1941 JND = 1.5 dB to 3 dB
Atal, et. al. 1962 ~ 1 dB
Jestaedt, et. al. 1977 JND @ 80 dB = 0.5 dB, JND @ 5 dB = 1.5 dB
Toole and Olive 1988 .25 dB for a 5kHz resonance, Q = 1Regardless, it's all academic. I don't understand why so many people keep posting that the difference is undetectable, when there are plenty of videos out now that show that it is. Is it a big difference? No. But it's certainly noticeable.
I haven't seen anyone mention it yet but the difference between 58 and 61 is 3 db. The difference between 59 and 62 is 3 db. Not 2 db
Haloweenhamster
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Got to agree with dscline my amp increments by 0.5db and I can hear a difference on each step
I was also testing some train horns this morning and at 3m with a reading of 91dba compared to 94dba there was a very noticeable difference
I was also testing some train horns this morning and at 3m with a reading of 91dba compared to 94dba there was a very noticeable difference
I noticed that, but I didn't post about it. Glad I wasn't alone.I haven't seen anyone mention it yet but the difference between 58 and 61 is 3 db. The difference between 59 and 62 is 3 db. Not 2 db
It does seem that most, if not all, of the comments from people who have heard them compared say that the difference is noticeable. But it is worth remembering that the human ear is significantly more sensitive to changes in frequency than amplitude. That complicates the question since in any given situation the new props are turning more slowly.
It doesn't take much ear sensitivity to notice half the sound.
A 3db drop is half the original in noise level.
A 3db drop is half the original in noise level.
ac0j
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The decibel (abbreviated dB) is the unit used to measure the intensity of a sound. The decibel scale is a little odd because the human ear is incredibly sensitive. Your ears can hear everything from your fingertip brushing lightly over your skin to a loud jet engine. In terms of power, the sound of the jet engine is about 1,000,000,000,000 times more powerful than the smallest audible sound. That's a big difference!
On the decibel scale, the smallest audible sound (near total silence) is 0 dB. A sound 10 times more powerful is 10 dB. A sound 100 times more powerful than near total silence is 20 dB. A sound 1,000 times more powerful than near total silence is 30 dB. Here are some common sounds and their decibel ratings:
Any sound above 85 dB can cause hearing loss, and the loss is related both to the power of the sound as well as the length of exposure. You know that you are listening to an 85-dB sound if you have to raise your voice to be heard by somebody else. Eight hours of 90-dB sound can cause damage to your ears; any exposure to 140-dB sound causes immediate damage (and causes actual pain). See this page for an exposure "ruler."
and:
The decibel (abbreviated dB) must be the most misunderstood measurement since the cubit. Although the term decibel always means the same thing, decibels may be calculated in several ways, and there are many confusing explanations of what they are.
The decibel is not a unit in the sense that a foot or a dyne is. Dynes and feet are defined quantities of force and distance. (You can go to the National Bureau of Standards and look at a foot or a dyne if you want to. They never change.) A decibel is a RELATIONSHIP between two values of POWER.
Decibels are designed for talking about numbers of greatly different magnitude, such as 23 vs. 4,700,000,000,000. With such vast differences between the numbers, the most difficult problem is getting the number of zeros right. We could use scientific notation, but a comparison between 2.3 X 10 and 4.7 X 10 to the 12th is still awkward. For convenience, we find the RATIO between the two numbers and convert that into a logarithm. This gives a number like 11.3. As long as we are going for simplicity, we might as well get rid of the decimal, so we multiply the number times ten. If we measured one value as 23 hp and another as 4.7 trillon hp, we say that one is 113dB greater than the other.
The usefulness of all this becomes becomes apparent when we think about how the ear perceives loudness. First of all, the ear is very sensitive. The softest audible sound has a power of about 0.000000000001 watt/sq. meter and the threshold of pain is around 1 watt/sq. meter, giving a total range of 120dB. In the second place, our judgment of relative levels of loudness is somewhat logarithmic. If a sound has 10 times the power of a reference (10dB) we hear it as twice as loud. If we merely double the power (3dB), the difference will be just noticeable.
[The calculations for the dB relationships I just gave go like this; for a 10 to one relationship, the log of 10 is 1, and ten times 1 is 10. For the 2 to one relationship, the log of 2 is 0.3, and 10 times that is 3. Incidentally, if the ratio goes the other way, with the measured value less than the reference, we get a negative dB value, because the log of 1/10 is -1.]
Just a couple blurbs from the first two websites that came up on a search for decibel....
After almost 30 years in the stereo equipment business, this is not the first time I have encountered people who have claimed to hear a 1db difference. Maybe yes they can, maybe no. More often they are convinced they can.
I have never seen a system the increased or decreased volume by less the 2 db per step. That would require the volume knob to have to make several full revolutions to go between minimum and maximum volume.
But I digress, I am still more interested in the performance of the blades, as they are basically NO quieter.
A more comfortable frequency does not equate to a quieter sound in db.
On the decibel scale, the smallest audible sound (near total silence) is 0 dB. A sound 10 times more powerful is 10 dB. A sound 100 times more powerful than near total silence is 20 dB. A sound 1,000 times more powerful than near total silence is 30 dB. Here are some common sounds and their decibel ratings:
- Near total silence - 0 dB
- A whisper - 15 dB
- Normal conversation - 60 dB
- A lawnmower - 90 dB
- A car horn - 110 dB
- A rock concert or a jet engine - 120 dB
- A gunshot or firecracker - 140 dB
Any sound above 85 dB can cause hearing loss, and the loss is related both to the power of the sound as well as the length of exposure. You know that you are listening to an 85-dB sound if you have to raise your voice to be heard by somebody else. Eight hours of 90-dB sound can cause damage to your ears; any exposure to 140-dB sound causes immediate damage (and causes actual pain). See this page for an exposure "ruler."
and:
The decibel (abbreviated dB) must be the most misunderstood measurement since the cubit. Although the term decibel always means the same thing, decibels may be calculated in several ways, and there are many confusing explanations of what they are.
The decibel is not a unit in the sense that a foot or a dyne is. Dynes and feet are defined quantities of force and distance. (You can go to the National Bureau of Standards and look at a foot or a dyne if you want to. They never change.) A decibel is a RELATIONSHIP between two values of POWER.
Decibels are designed for talking about numbers of greatly different magnitude, such as 23 vs. 4,700,000,000,000. With such vast differences between the numbers, the most difficult problem is getting the number of zeros right. We could use scientific notation, but a comparison between 2.3 X 10 and 4.7 X 10 to the 12th is still awkward. For convenience, we find the RATIO between the two numbers and convert that into a logarithm. This gives a number like 11.3. As long as we are going for simplicity, we might as well get rid of the decimal, so we multiply the number times ten. If we measured one value as 23 hp and another as 4.7 trillon hp, we say that one is 113dB greater than the other.
The usefulness of all this becomes becomes apparent when we think about how the ear perceives loudness. First of all, the ear is very sensitive. The softest audible sound has a power of about 0.000000000001 watt/sq. meter and the threshold of pain is around 1 watt/sq. meter, giving a total range of 120dB. In the second place, our judgment of relative levels of loudness is somewhat logarithmic. If a sound has 10 times the power of a reference (10dB) we hear it as twice as loud. If we merely double the power (3dB), the difference will be just noticeable.
[The calculations for the dB relationships I just gave go like this; for a 10 to one relationship, the log of 10 is 1, and ten times 1 is 10. For the 2 to one relationship, the log of 2 is 0.3, and 10 times that is 3. Incidentally, if the ratio goes the other way, with the measured value less than the reference, we get a negative dB value, because the log of 1/10 is -1.]
Just a couple blurbs from the first two websites that came up on a search for decibel....
After almost 30 years in the stereo equipment business, this is not the first time I have encountered people who have claimed to hear a 1db difference. Maybe yes they can, maybe no. More often they are convinced they can.
I have never seen a system the increased or decreased volume by less the 2 db per step. That would require the volume knob to have to make several full revolutions to go between minimum and maximum volume.
But I digress, I am still more interested in the performance of the blades, as they are basically NO quieter.
A more comfortable frequency does not equate to a quieter sound in db.
It doesn't really complicate things at all. Whether it sounds quieter because the sound pressure level is reduced (confirmed with a meter), or sounds quieter because the it's in a more pleasing frequency range, the result is the same: it sounds quieter. Isn't that what's important? Whether the level of improvement is worth replacing perfectly good set old style props is a completely different question, and a personal choice.
That's very strange. I can say from experience even consumer grade AV receivers from Onkyo and Denon have increments of 1db, with 0db being reference level. My current (Denon) receiver does 0.5db, as I mentioned.
Most home audio receivers/processors don't have mechanical volume controls any more. With multiple channels, room correction processing (like Ausyssey, etc.), and other processing, it's all digital these days. The knobs will spin around as many times as you like, if you're actually using the knob.
I agree with you that the performance of the blades may be a more practical consideration. That doesn't detract from the fact that sound is important to many, and many can apparently tell the difference.
Haloweenhamster
Well-Known Member
I completely agree that it doesn't matter why it sounds quieter/better from the point of view of using the new props - I'm waiting for mine to arrive. I was just pointing out that the subjective improvement may be as much about pitch as about amplitude, which may account for the extent of the subjective improvement relative to the more modest measured reduction.
You definitely can notice 3db. When you calculated, you forgot to multiply the log. Also know that the formula is based on a ratio of power out to the power in. if you took a stereo and increased the power to the speakers from 5 watts to 10, would you notice it? How about 10 to 20? or 20 to 40?
Each of those is 3db. Use the formula above 10 log Power A/Power B. (The actual is Power out over Power in) For 5 to 10 watts, you take 10 divided by 5 which is 2. Take the log of 2 (use your calculator), it equals .301. Multiply by 10 and you get 3 db.
Also 0db is not total silence. Not even close. It is however near silence to humans.
Changing to a more comfortable frequency (usually lower) can definitely equate to a quieter db level at the uncomfortable frequency. Interesting thing is that the lower frequency will travel farther, given the same starting db level.
Each of those is 3db. Use the formula above 10 log Power A/Power B. (The actual is Power out over Power in) For 5 to 10 watts, you take 10 divided by 5 which is 2. Take the log of 2 (use your calculator), it equals .301. Multiply by 10 and you get 3 db.
Also 0db is not total silence. Not even close. It is however near silence to humans.
Changing to a more comfortable frequency (usually lower) can definitely equate to a quieter db level at the uncomfortable frequency. Interesting thing is that the lower frequency will travel farther, given the same starting db level.
Which is exactly why I previously guessed as a reason why DJI quoted the db advantage at TO/Landing... when it's further away, the Platinum acoustic advantage may disappear due to the greater attenuation of higher frequencies from the original MP.
Chip
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The decibel (abbreviated dB) is the unit used to measure the intensity of a sound. The decibel scale is a little odd because the human ear is incredibly sensitive. Your ears can hear everything from your fingertip brushing lightly over your skin to a loud jet engine. In terms of power, the sound of the jet engine is about 1,000,000,000,000 times more powerful than the smallest audible sound. That's a big difference!
On the decibel scale, the smallest audible sound (near total silence) is 0 dB. A sound 10 times more powerful is 10 dB. A sound 100 times more powerful than near total silence is 20 dB. A sound 1,000 times more powerful than near total silence is 30 dB. Here are some common sounds and their decibel ratings:
You know from your own experience that distance affects the intensity of sound -- if you are far away, the power is greatly diminished. All of the ratings above are taken while standing near the sound.
- Near total silence - 0 dB
- A whisper - 15 dB
- Normal conversation - 60 dB
- A lawnmower - 90 dB
- A car horn - 110 dB
- A rock concert or a jet engine - 120 dB
- A gunshot or firecracker - 140 dB
Any sound above 85 dB can cause hearing loss, and the loss is related both to the power of the sound as well as the length of exposure. You know that you are listening to an 85-dB sound if you have to raise your voice to be heard by somebody else. Eight hours of 90-dB sound can cause damage to your ears; any exposure to 140-dB sound causes immediate damage (and causes actual pain). See this page for an exposure "ruler."
and:
The decibel (abbreviated dB) must be the most misunderstood measurement since the cubit. Although the term decibel always means the same thing, decibels may be calculated in several ways, and there are many confusing explanations of what they are.
The decibel is not a unit in the sense that a foot or a dyne is. Dynes and feet are defined quantities of force and distance. (You can go to the National Bureau of Standards and look at a foot or a dyne if you want to. They never change.) A decibel is a RELATIONSHIP between two values of POWER.
Decibels are designed for talking about numbers of greatly different magnitude, such as 23 vs. 4,700,000,000,000. With such vast differences between the numbers, the most difficult problem is getting the number of zeros right. We could use scientific notation, but a comparison between 2.3 X 10 and 4.7 X 10 to the 12th is still awkward. For convenience, we find the RATIO between the two numbers and convert that into a logarithm. This gives a number like 11.3. As long as we are going for simplicity, we might as well get rid of the decimal, so we multiply the number times ten. If we measured one value as 23 hp and another as 4.7 trillon hp, we say that one is 113dB greater than the other.
The usefulness of all this becomes becomes apparent when we think about how the ear perceives loudness. First of all, the ear is very sensitive. The softest audible sound has a power of about 0.000000000001 watt/sq. meter and the threshold of pain is around 1 watt/sq. meter, giving a total range of 120dB. In the second place, our judgment of relative levels of loudness is somewhat logarithmic. If a sound has 10 times the power of a reference (10dB) we hear it as twice as loud. If we merely double the power (3dB), the difference will be just noticeable.
[The calculations for the dB relationships I just gave go like this; for a 10 to one relationship, the log of 10 is 1, and ten times 1 is 10. For the 2 to one relationship, the log of 2 is 0.3, and 10 times that is 3. Incidentally, if the ratio goes the other way, with the measured value less than the reference, we get a negative dB value, because the log of 1/10 is -1.]
Just a couple blurbs from the first two websites that came up on a search for decibel....
After almost 30 years in the stereo equipment business, this is not the first time I have encountered people who have claimed to hear a 1db difference. Maybe yes they can, maybe no. More often they are convinced they can.
I have never seen a system the increased or decreased volume by less the 2 db per step. That would require the volume knob to have to make several full revolutions to go between minimum and maximum volume.
But I digress, I am still more interested in the performance of the blades, as they are basically NO quieter.
A more comfortable frequency does not equate to a quieter sound in db.
Okay but what are you saying? (Im sorry but I felt like being a wiseacre).
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