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
I agree, it takes many hours to dial them in. At first it was a bit frustrating, but after I got the basic formula figured out, it was a lot of fun. What a nerd I am. My wife just shakes her head :-) as we go through the local antique marts looking for the right containers. 
Thanks Boxer...

I think that relatively to the particular room, and relatively to one another, the carafe,bottles,containers, may complement each other in the cleaning of the acoustic field frequencies, modulo some little expriment with volume and the length and perimeter of the straws or the equivalent device... 
I have 10 total. 4 are the 500 ml flasks / 2 are 250ml / 1 is a 125ml pyrex boiling container / The remaining 3 are carafes with wide bases & long necks. I agree that the improvement is astounding. Never expected it.  
boxer12
Boxer how many flasks do you use? I beat you for the price, I use 20 containers, plastic, glass, wine refiner, carafe, 2 with 5 gallons volume 2 with 3 gallons, the others between 500 milliter and 1 liter...


The effects on the dynamic and clarity and bass depth are astounding...
The glass 500ml volumetric flasks work great. They are a bit more sensitive than the other containers I've used. Filling them 16% full (with cutting oil) while using a .140 hole an inch & a half in length.  I bought the flasks on amazon at 4 for $32. I believe individually they are around $10. Pretty cheap tweek indeed!
For the moment my experiments were very conclusive with thin staw compress to half of their original diameter,not more than 2 or 3 inches long, inserted in the plastic wrapped sheet at the nozzle of my varied carafe,bottles,or 3 or 5 gallons plastic and glass container+ only a minimal volume of water 1 inches...The results are so great that I will wait a bit to replace all that, cost is almost nothing...The impact on sound was so great that any other upgrade is probably less an upgrade than that cheap resonators room’s tweak...This thread is only to inform the newcomers about that... I am thankful for any suggestion about improving that for sure...Thanks then to Ozzy for that...
Very useful and astute observations...thanks very much  and my best to you….
Some of my tips for this tweek.

1. Instead of using the "slush" straws how about using tubing perhaps the size used for ice maker's?. Or some teflon tubing used for interconnects. That way you can experiment with the length and/or the diameter of the tube. 

2. For a container, perhaps use PVC pipe with reducers, caps etc. for further experimentation. You can even coat the inside/ outside with Graphene.

3. Perhaps use some oil in sealed pouches inside the PVC pipe cannisters that won't evaporate as easily.

BTW, tweak1 you need to get some netting...

ozzy
I ordered four 500ml volumetric glass lab flasks yesterday to mess around with. These have very long thin necks & are about 4" at the base. I'll let you know how they work out. 
I gain some better results by cutting the diameter of regular straw in half and shorten the regular straw to  around 2 inches in many of  my carafe or in  some of my big glass container 3 or 5 gallons but not all of them...It is necessary to experiment in your particular rooms to go for the best.... I will never listen music in a room without resonators now...Great impact... my best to all...
whitestix, It costs almost nothing to try this. Give it a try if you haven't. While you're at it, put some crushed quartz on your walls as well. That also helps clean things up.
With all due respect, wheatstix, he got them from your friend and humble scribe. Hel-loo!
WFT, GK has met his match in terms of bizarre audio tweaks.  I didn't think anyone could be as far out as GK, but this cat clearly is.  Kindred spirits, they are.  Way too damn funny.  
Mahgister you have15 carafes and several jerrycans in your room now? that’s a lot of stuff stashed around your room. Have you tried to control room acoustics or resonance any other way? There are types treatments that are easier to live with. 
boxer12
mahgister,
I don't think there is anything wrong with your method, so I hope you didn't take it that way. My only problem with the straw was the hole diameter being to large for the results I was looking for. I have a small metal working machine shop in my basement so all I'm doing is machining caps (or plugs) for the bottles & drilling a .125 hole (1/8") in the solid cap then placing a chamfer on both ends of the hole. The chamfer is about 60 degrees and approx. .100 deep & should help the air move in and out of the bottle a little more efficiently. Total length of the cap is about 1.5" to 2" long. It also appears that the fat bottom long neck bottles work best, as you already discovered. Hope this helps.  


Yes thanks Boxer that's help much to figure the idea....My best to you...
mahgister,
I don't think there is anything wrong with your method, so I hope you didn't take it that way. My only problem with the straw was the hole diameter being to large for the results I was looking for. I have a small metal working machine shop in my basement so all I'm doing is machining caps (or plugs) for the bottles & drilling a .125 hole (1/8") in the solid cap then placing a chamfer on both ends of the hole. The chamfer is about 60 degrees and approx. .100 deep & should help the air move in and out of the bottle a little more efficiently. Total length of the cap is about 1.5" to 2" long. It also appears that the fat bottom long neck bottles work best, as you already discovered. Hope this helps.   
mahgister  Very Interesting, I also have, years ago, a small platic cube, with a hole, fix to the back of my speakers and only just a half inch, up or down the back of the speaker would transform the sound !  May be You should post a video on YouTube:  Helmholtz Bottle with straw.  Thank you 



boxer122,282 posts06-06-2019 9:22pmI think I've got the formula worked out for my room now. I'm at 8 of them right now & it's sounding better than ever. Great "tweak". It appears that the straw wasn't working well for me so I'm using a .125 hole (with a large chamfer at both ends) at about an 1 1/2 in length. I'm also using cutting oil (very thin) instead of water.



Will you explain more what you said? I am not sure to understand...I use thin straw inserted I a wrapped plastified sheet at the nozzle...It seems you proceed not in the same manner... I will appreciate a more detailed description...
I think I've got the formula worked out for my room now. I'm at 8 of them right now & it's sounding better than ever. Great "tweak". It appears that the straw wasn't working well for me so I'm using a .125 hole (with a large chamfer at both ends) at about an 1 1/2 in length. I'm also using cutting oil (very thin) instead of water.

Geoff & Mahgistar, Thanks for bringing this one to the forefront!  


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.
Geoff please add more details to the box used to find resonance peaks. Is there a particular volume of box that works best at that frequency? Is it sealed airtight or just closed? 

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! 🏄‍♀️
I suspect it wouldn’t take very long for millercarbon to accumulate a nice pile of wine bottles. 
I had great results with carafe, jerrycan. or 5 gallons plastic bucket or glass bucket with regular straws inserted in the nozzle... Keg is a bit too small volume...
It could take a while to accumulate all those wine bottles. Could I just use a keg instead?
A last remark: it seems that regular straws are better than slush straw in general with jerrycan,or bucket, carafe etc ...Greater clarity all across the range...
Or your resonator Geooff , I just look to your new product on your site...Alas! I cannot afford that now... But perhaps I will emulate it ...
Interesting food for tought, thanks Geoff...I will meditate about this crucial fact ...
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.
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?
My 15 foot long Helmholtz resonator wasn’t more than 10 feet long. OMG 😲 
My wife measuring herself 5 feet 6 inches does not appreciate any object bigger than 10 feet in one of his room... sorry ...
My room has 15 feet lol.... On top of the speakers ok I will try that one day for sure thanks for the suggestion....I cannot try that now because of what I already had on top lol...And the sound now is too much better to dreaming improve it easily for the moment...
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. 
The difference with your glass is that a straw is inserted in the bottle and they act as resonators better one I think that the open  glass...I dont doubt that anything near speakers affect speakers sound I know that by experience tough...
I already had behind the speakers bottles of water... and near each speakers another one for resonators... It works...
I cannot put even a glass of water in front of my speakers on the desk anyway.... Thanks for the suggested  experiment anyway...
Geoff I am not enough clever to sort out if you mock me or want to help, probably the two in the same times ...But I like your spirit anyway... My best...
I think I am done now... All is better, the dynamic, the natural instrumental timbre of instruments, the successive holographic layers of sound in an enveloping  fashion (I am in nearfield listening but the final result are way better also for room listening anywhere in the room)... I think that the varied bottles,carafes, jerrycans, and glass buckets, correct mutually each other their deficiencies and the final results are at my amazing satisfaction, with for example a bass clarity and depth incredible for my 7 inches Mission Cyrus 781 drivers...One year ago I dreamed to add a sub to my system, it is no more necessary, and absolutely without any more interest...I am done and bewildered more than yesterday...It is the end of this story...My best to all...
Maybe you can try cups of ice water on the desk. 😬 Where there’s a will there’s a way.
For those with enough disposable income, there are sets you can buy if you google it. Here's a link to a complete set of resonators but these are not for sale: https://utsic.utoronto.ca/wpm_instrument/helmholtz-resonators/
Just click on the photo to get a better view.

All the best,
Nonoise