> The team reduced the overall leaf blower noise by about two decibels, making the machine sound 37% quieter.
While a 2 dB reduction in noise does represent a 37% reduction in acoustic power, our perception of sound is logarithmic so this is extremely unlikely to "sound 37% quieter"-- Assuming the reduction is from 50 dB to 48 dB, it will sound about 4% quieter.
Much more significant is the 12 dB reduction in the "shrill and annoying" frequency range. While the 94% reduction there is probably also overstated for the same reason, the initial power level in that range will be only a portion of the overall noise output-- I wouldn't be surprised if there's a 50-75% perceived reduction of noise in this range.
With that in mind, I wonder how much, if at all, the reduction would be if the entire nozzle were designed this way, instead of just the end bit.
Those higher frequencies travel farther than the lower frequencies, so cutting them has a bigger perceived effect (and this is all about perceived effect, I believe, not the health effects of the operator).
Just agreeing with you that acoustics is complicated and non unidimensional.
Most of the leaf blower noise in neighborhoods is cleaning up tiny grass clippings off of driveways and sidewalks instead of handling the Fall season's dead leaves, like this: https://www.youtube.com/watch?v=ak5VoB-ceeU&t=0m06s
Rakes don't help with grass cuttings. People could use brooms to sweep up the grass but homeowners and lawn crews don't do it that way because -- like the rake -- it requires more work and takes a lot longer than using noisy blowers.
I have a leaf blower, and I use it for about 5 minutes a week in the summer to clear grass clippings from walkways after I mow. I don't like being "that guy", so I pretty much run around the yard with it in order to finish as quickly as possible.
I know that the electric leaf blowers are quieter, but my neighbor's makes a high pitched squeal which bothers me more. I think that she has some sort of condition, because she's literally using the thing for about three hours a day. I don't know how many battery packs she has, but she runs it until it dies, swaps the pack, and gets back to it. It's not a huge yard, maybe 1/3 of an acre, but she is compelled to get every blade of grass off of her driveway.
If it was that guy's job to use a rake and broom instead of a leaf blower, the same amount of cleaning would be done.
I suppose these days people take techno-efficiency over all else to the point of ruining the environment, other people's peace, their own air quality, their own wallet, and so on, all so that they can blow the leaves off of their lawn in a supposedly shorter time or for slightly less effort.
I am agreeing with you, for the record. It seems silly to throw leaves in a landfill.
The (major) manufacturer they demonstrated it to seems to have adopted it.
Maybe they'll expand the concept out over time to the two stroke ones as well. :)
But, keep in mind that "just going electric" isn't a good option universally. It's MUCH more expensive to put together an electric setup and the number of batteries necessary to do any significant amount of work than it is to buy even a mid range backpack 2-stroke blower. Especially if you do what a lot of people do and look for used equipment to save a ton of $.
If you have a small yard or are only ever doing stuff like blowing off a deck/patio/sidewalk/driveway: battery 100%. if you need to do any significant amount of leaf management in a larger area: good luck.
I have an m18 electric, and gas Echo backpack. If im cleaning off a sidewalk/patio, cleaning gutters, etc.. im 100% using the electric. Otherwise....not so much. I don't even clean up grass clippings, mulch and cut frequently enough that they aren't an issue.
As a side note, leafblowers aren't just disruptive to the sound environment: https://twitter.com/touchmoonflower/status/17242321111447757...
I hate it. And it serves no ecological purpose.
At least from my experience, it's not done for ecological purposes. It's primarialy done to clear pathways for safety, maintenance, and aesthetics.
Some people do blow a whole lawn, but that never struck me as useful. Cleaning up the path is nice though, and depending on your paths, makes plenty of noise already.
My neighborhood has a landscape crew do the leaves in the common areas 3x season. If we just had them do the paths and parking lot, it would be half the time (or less) with blowers.
Sucks to be an earthling trapped here with leaf blower jerks.
Though I know some tools, such as branch shredders are regulated in some residential areas, but I don't frequent those.
I don't care about leaves on the lawn.
They're the worst. A noise pollution posterchild.
Second, it dampens the noise while retaining all the force.
If this works out, it will be amazing! Kudos to the student teams!
That said, I prefer just raking up leaves manually. It makes no noise, it's quiet, and it's good exercise.
I think a lot of folks in these discussions think only of lawns. That's a pretty small portion of where leaf blowers get used, in my experience. The lawn mower takes care of most of the leaves on the lawn, the blower gets used around bushes and other places a rake won't work at all.
1. mine jams extremely easily when sticks or wet leaves get into it 2. their ability to actually move leaves is significantly less when in suck mode vs blow mode, this is not specific to moving leaves, try sucking sugar throw a straw vs blowing it, blowing moves stuff MUCH more.
I have an electric blower that I use for getting leaves off my decks (you can't rake a deck and it's actually a remarkable pain in the ass to brush leaves off a deck) but if I got a contractor in to do my garden (which I don't, they just get mowed over) then they would certainly have a gas blower.
Although quieter than the gas ones, it's still far from silent and the noise is still annoying but higher pitch. Like a high-pitched vacuum cleaner noise.
Most people have the much louder gas ones though, they're the worst, and anecdotally the people operating the gas ones seem to rev them up and down more which makes it even more annoying.
Every time I hear one, I have nothing but negative thoughts about the person using them, and disgust for the society that allows them to ruin the environment for such minimal benefit.
A rake works almost silently... but then you can't irritate everyone within a kilometer radius.
