Noisy vacuum cleaners

xunxine

I was studying when something disturbed me. Why are vacuum cleaners so noisy? Is there such a thing as a silent vacuum cleaner?

InTuoVultu

Any time something hard hits something else hard it deforms and vibrates. If this vibrations is an audible frequency you hear it. When you have a gear box and motor there are a lot of hard things hitting each other all the time. So pretty much any thing that moves enough, like the pump in a vacuum cleaner makes noise.

On top of that you got all the rushing air coming and going across complicated surfaces and boundaries flowing in chaotic ways impossible to calculate. All this makes for a great deal of vibrations in the air which you also hear.

You're never going to get a perfectly quiet vacuum. You could put a lot of effort into designing a quiet-er vacuum like people have put effort into designing quiet cars, but that would just make the vac more expensive.

redargon

I saw a tv advert for a silent vacuum cleaner (from Dyson, I think) where you can hear a cat licking his paw, but you can't hear the vacuum cleaner. How true that is, I have no idea, but I think there must be some reasonably quieter (read expensive) models on the market.

f95toli

To a large exent because people do not want to buy silent vacuum cleaners. There have been several attempts to market silent models but they simply do not sell very well.
Most of the large companies that sell household appliances have whole departments where sound designers (and yes, that is actually a job title) work with the engineers to come up with just the right "sucking" sound for the vacuum cleaner.

Note that there are of course limits to just HOW silent you could make a vacuum cleaner if you really tried; but the main point here is that most of the models you find on the market are actually quite a bit louder than they have to be for technical reasons.

Sound design has become increasingly important marketing tool over the past few years and many of the sounds you hear do not sound the way they do by accident (another obvious example is the sound a car makes)