Comment on Students’ Leaf Blower Suppressor To Hit Retail
A_A@lemmy.world 7 months ago
was posted 3 days ago in /c/Technology, here :
lemmy.world/post/15468260
what they did :
“Our product takes in a full blow of air and separates it,” said team member Leen Alfaoury. “Some of that air comes out as it is, and part of it comes out shifted. The combination of these two sections of the air makes the blower less noisy.”
Adds Chacon: “It ultimately dampens the sound as it leaves, but it keeps all that force, which is the beauty of it.”
Their design cuts the most shrill and annoying frequencies by about 12 decibels, which all but removes them, making them 94% quieter.
Just saying it doesn’t decrease the power is a norm claim without providing anything technical to support it.
I’ve read multiple articles and videos and yet this very crucial information is intentionally not included.
The claims are false, you can’t suppress or mute something with a tradeoff, unless they have somehow magically figured out physics anomalies.
Are you saying novel mechanical engineering designs are impossible? That the mechanism of a leaf blower is so near perfection, that a well funded team of 4 mechanical engineering students could not, without VIOLATING THE LAWS OF PHYSICS, have simply found a better mechanism?
I agree with your “show me the numbers” critique, but I find your complete disregard of what may be a better answer without any data at all to be equally foolhardy.
I am saying every single one of these claims have never wound up being actually true since they go against the very nature of physics. Yet people perpetuate the claims and defend them without the supporting data.
never wound up being actually true since they go against the very nature of physics.
This is an incredibly wild statement when you have no data on the device’s construction or operation.
Youre complaining about a lack of data then making wild assumptions about it with no data.
Not exactly good science here, mate.
You’re right to be sceptical until more data is presented, but saying no claim of progress is ever true is quite obviously a gross misrepresentation of our current reality. You are doing this on digital devices interconnected with millions of users ar staggering speed and latency. Every part of which are scientific claims.
You being downvoted is pretty crazy… Your statement is valid
There’s a relevant physics anomaly called a Helmholtz resonator, or more broadly waveform interference.
Destructive interference is a thing. The energy m the vibrations doesn’t go away, however you CAN shift that energy into different frequencies and destructive interference done correctly will effectively shift it into so high frequencies that the vibrations are better compared with heat than with sound (what is heat convection if not extremely high frequency sound? :)
Even increasing or decreasing the length of the discharge tube will change its power and CFM and they’ve added 8”. There is no way the aerodynamics and the overall performance isn’t affected.
12dB is literally nothing when the lawn dudes are blasting 60-100db
Decibel scale is logarithmic, which means 10db change is reducing perceived volume by half.
No. It means the sound energy is dropped by half. Our audio perception is also logarithmic however. It’s why we use db.
Almost. a 10db change is a 10x difference in power and roughly 2x difference in perceived loudness
12 dB is a pretty decent reduction if your goal is hearing protection, 100->88 is also bringing it to something that absolutely needs hearing protection to something that’s borderline acceptable for an 8 hour shift depending on your local laws, mine say 4 hours but still, way more comfortable to use.
The team reduced the overall leaf blower noise by about two decibels, making the machine sound 37% quieter.
It’s an significant 2db
Reading the article, reducing the shriller frequencies by 12db is still pretty nice, looks like it’s designed for electric blowers which are already way quieter than gasoline powered ones, already generally in the hearing safe range. 2db overall should still be noticeable though, be generally less annoying.
Eh, I’ll take it though. I live in a fairly quiet part of town but the street has gotten pretty busy in the last could of years. And visually, I guess the street seems to open up making drivers get… spicy now and then. The fucking motorcycles, man. These noisy fucking middle-aged infants making 130 decibels while only going 15mph make me see red. I’d gladly take the lawn equipment noise.
The team reduced the overall leaf blower noise by about two decibels, making the machine sound 37% quieter.
It’s an insignificant 2db, I don’t know why buddy didn’t provide the relevant information.
Decibels are a logarithmic scale, so it scales exponentially. Because of this, reducing by just ten is actually very significant and would reduce the perceived volume by half, and would reduce the actual sound pressure even more than half.
The team reduced the overall leaf blower noise by about two decibels, making the machine sound 37% quieter.
It’s an insignificant 2db, I don’t know why buddy didn’t provide the relevant information.
NeoNachtwaechter@lemmy.world 7 months ago
This “conversion” from decibel to per cent is more than ridiculous.
MentalEdge@sopuli.xyz 7 months ago
Why? dB is logarithmic so it’s difficult for people to picture how loud something is, if that’s the only number given.
wewbull@feddit.uk 7 months ago
And so are our ears. That’s why we use db. So 12db is not perceived by us to be 94% quieter.
webghost0101@sopuli.xyz 7 months ago
So its 94% less sound because this seems sound calculated -12db in % with conventional formulas?
How would we describe perceived sound exactly, not many people can imagine something when given a db value? Maybe we should?
A_A@lemmy.world 7 months ago
Well, 93.75% to be more exact. Did you recalculate it yourself ?
SchmidtGenetics@lemmy.world 7 months ago
You omitted the most important data, it’s 2db overall, not 12db.
So your own “recalculation” isn’t even in the right ballpark as the correct answer.
Its people that misinterpret the information and perpetuate it like you are doing here that makes these look far better than they actually are.
NeoNachtwaechter@lemmy.world 7 months ago
The perception of noise is quite complicated. But as a rule of thumb: when some noise changes by -10dB, then you hear it about “half as loud”.
Source: I have a university degree in acoustics.
So for the reduction of -12dB here, it will be perceived as “nearly half as loud”. Very different than the “94%” is suggesting.
SchmidtGenetics@lemmy.world 7 months ago
It’s also only 2db overall, the one frequency they dropped that much.
A_A@lemmy.world 7 months ago
We agree that the -12dB is what’s important for human hearing … Now, you may agree that the 94% reduction is what counts regarding engineering // fabrication // design.