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Helmhotz resonators for audiophile at almost no cost and without calculus...

The importance to treat the room if you have speakers, even in nearfield listening like me, is imperative ...

Here is my advice: 

Buy some big  empty wine bottles, or drink them before, it is optional....Or use some carafes, the kind that some display at the center of a table....I use plastic  wrapping sheets to tightly seal the aperture of the bottles and the carafes after pouring in them around 10 % of water in their volume space...You must listen and experiment for your taste and room to determine the exact amount of water to boost the frequencies that will benefit….After that  I peirce the plastic sheet with a needle and I insert a  thin straw with only the extremity of the straw at the top...  That its! You know have an Helhmotz resonator... 

You now have one of the more astounding tweak for a room that will transform your listening space in sound heaven ...I use more than 15 of them in my little audio room and trust me that is one of a kind upgrading...

I wrote that for those who want to experiment, the others can stay silent...My best to all...
128x128mahgister

Showing 17 responses by geoffkait

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geoffkait
23,365 posts
 
With all due respect, wheatstix, he got them from your friend and humble scribe. Hel-loo!
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geoffkait
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I used a box about the size of a USPS box size 18x12x4 or any medium size box will work. 200-500 cu. in. Sealed. Cavity resonance. You will feel the box vibrate in your hand when the box enters a standing wave zone or other pressure peak zone. The average volume in the room should be moderately loud since a certain level of energy is needed to make the box vibrate. It would not work for low volume.
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geoffkait
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Having a bunch of Helmholtz resonators in the room is like having the air (medium) in the room on springs, what with the spring rate of air and air being a compressible fluid. A smoother ride for the acoustic waves? Catch the wave! 🏄‍♀️
geoffkait's avatar
geoffkait
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I suspect it wouldn’t take very long for millercarbon to accumulate a nice pile of wine bottles. 
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geoffkait
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😢
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geoffkait
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Aren’t tiny little bowl resonators really Helmholtz resonators with very small volume, relatively large nozzle cross sectional area A and very small nozzle length L?

The resonant frequency of the Helmholtz resonator is directly proportional to the square root of the cross sectional area of the nozzle A and inversely proportional to both the square root of the length of the nozzle L and the square root of the volume V. Thus, very small volumes can have very high Fr.
geoffkait's avatar
geoffkait
23,365 posts
 
Spoiler alert 🚨

It was a folded horn, three straight sections of pipe, each five feet long, connected by elbow joints. 📎 Leaned up against the rear wall it hardly took up any space at all. 🤗

Pop quiz - How long is a tuba if unfolded?
geoffkait's avatar
geoffkait
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My 15 foot long Helmholtz resonator wasn’t more than 10 feet long. OMG 😲 
geoffkait's avatar
geoffkait
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My room was 14 feet. Necessity is the mother of invention.
geoffkait's avatar
geoffkait
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The cups of water need to be in front of the speakers. Have you put a resonator on top of the speakers yet? I once built a Helmholtz resonator that was fifteen feet long. 
geoffkait's avatar
geoffkait
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I’m sure you could if you really wanted to. 😃
geoffkait's avatar
geoffkait
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That’s what everyone says. Would I kid you? 
geoffkait's avatar
geoffkait
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Maybe you can try cups of ice water on the desk. 😬 Where there’s a will there’s a way.
geoffkait's avatar
geoffkait
23,365 posts
 
Actually all you need to have is a temperature differential of 20 to 30 degrees F to hear the bowls of water. That means you can get by with cold tap water. Putting ice in the water is just uh, icing on the cake and to add some complexity. 😬 I debuted the bowls of water tweak at CES in the Golden Sound Room in 2005. My, how time flies! 🔙

Am I in shape now? 🏋🏻‍♂️
geoffkait's avatar
geoffkait
23,365 posts
 
Hey, that reminds me! 🤗 Has anyone tried the water bowl tweak? Here’s how it works. You place three medium size bowls of *ice water* on the floor about two feet out from the speakers, one bowl in front of each speaker and one bowl between the other two, so the bowls of ice water are in a row left to right.
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geoffkait
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Note - for a given volume V of the bottle the operating frequency of the resonator is completely controlled by the neck or nozzle, length and cross section area. Everything else in the Helmholtz equation is a constant.
geoffkait's avatar
geoffkait
23,365 posts
 
You can find sound pressure peaks using an empty sealed box and a test tone (for example 315 Hz). Walk around the room holding the box with test tone playing moderately loud on REPEAT. When the box starts to vibrate in your hand that’s where a sound pressure peak is located. Some places where you will probably find these sound pressure peaks are room corners on the floor and ceiling, first reflection points on wall and floor, about a foot directly above speakers, behind and in middle of speakers at rear wall, on floor in front of and in between speakers. Just placing a vase or bottle on top of speakers should be audible although it may hurt the sound if not pre-designed, I.e., just an arbitrary vase/bottle.
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