Helmholtz Sound Absorption Demo

[@orioldepagesmoyes5978]

The best video I have ever seen on Helmoltz resonators. The air contained in the neck is the mass and the air contained inside the box is the spring. The absorption is reduced when the cottons cover the neck of the resonator.

[@sh1maru]

So theoretically we can build an effective absorber based on an array of bottles?

[@imflying2953]

great demo. building my on Helmholtz boxes atm and this clearly demonstrates the importance of proper absorption. thank you.

[@audioprotaro1338]

"unless you are somebody who has tried to used an online calculator to build a Helmholtz resonator and wondered why it didn't do anything." Yup. Thanks for the video!

[@2eulogy2]

Thanks for taking the time to conduct this demonstration and upload the video. Im in the middle of experimenting with helmholtz resonators for controlling low end in my studio, this has inspired me to try some new things see if i can get my room response a little more where i want it.

[@ranna.]

Superb, Amazing DEMO, God bless.... Thanks

[@Chente_Bui]

This is awesome. Thank you I find this so helpful yet now I have so many more questions!

[@TheNickmeeks1]

So just to be clear. Raise in volume is adding to the sound in the room and the dips are subtracting to the sound in the storm. Or it a rise in volume in the bottle showing how much the bottle is lowering the sound in the room?

[@izzybella36912]

This was a very helpful demonstration. I'm trying to figure out how to build one or more myself.

[@Travelin_Light]

So the sound absorbing material, as long as it's not too too dense wont shift the resonant frequency of the box you build? Correct?

[@richardjones38]

Interesting demo, but it'd be a lot better if it included an explanation of what it is you're demonstrating. I assume you're using the change in resonator volume due to adding the cotton balls to tune it's resonant frequency?

[@greatfelixo]

I am also confused with this and wondering if you ever got your head round it. I have 2 other theories as to what the dampening is doing. 1.) the destructive phase wave that the bottle sends back out has a higher amplitude than the pressure wave going in so it needs the cotton to absorb some of the energy so that the amplitudes are closer and therefore better cancel each other out. Not sure this is physically possible though because where is that extra energy coming from. 2.) the surfaces of the bottle vibrates in sympathy so the cotton balls are just stopping these surfaces producing sound. Although if this is the case I don't understand how after a certain amount of cotton balls it starts going back the other way.