ringing aluminum round horn (how to damp? :: Pics incl.)

[ARIYAHOOR]

I built a 217hz round horn using aluminum, everything is as would be but horns ring! I want opinion on how to damp the outer side of the horns...

horn parameters:

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An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

 

[DrBoar]

The Q of resonances in such stiff material as aluminium should be very high so you should just need to cover a small part of the horn.

Car DIY stores sells selfadhesive bitumen pads, usually 4mm thick. This is usually but not allways pliable/elastic. If it is hard and brittle they are to old. There is also a thinner version that appear to be cardboard soaked in some resin.

Lastly we have heat and sound reflective rubber foam self adhesive with a metal foil coating (used for insulation of engine compartments of cars and boats)

I would cut strips 3-5 cm wide, then use double sided tape to try out ring or radial patterna of the damping pads. When I had something that both works vibration wise and looks I would peel of the protective paper backing and use the self adhesive.

The ones I have used tend so leave quite a lot of sticky glue if you remove them so if you want to remove them the tape leveas less of a mess🙂

 

[ARIYAHOOR]

Oh thanks for the help... I'll look if can find the stuff... horn itself is very well-made tractrix and sounds good but I could detect the ringing even in low volume listening ... I've got double sided tap...
thanks again

 

[el`Ol]

Adhesive paste for photographers is more expensive than bitumen, but better to your health.
Walimex - Shop - walimex Adhesive Paste Value Pack 300g No. 17368 walimex Adhesive Paste Value Pack 300g No. 17368 17368

 

[fpitas]

I used this stuff to damp my 511Bs:

Amazon.com: QuietCoat: Musical Instruments

It got a great review, although I wrote the review ;-)

 

[bear]

also possible is the stuff used for roofing - it is a thick rubberized/bitumen sheet with adhesive on one side. Usually sold for "ice & water" - for example around skylights. Very heavy and dead.

Some is heat applied, some is self stick.

I'd make strips and run them from the rear to the front. Or else make a long thin strip or two with a knife and wrap the horn in a spiral from throat out... you can likely do the entire horn that way...

_-_-bear

 

[theAnonymous1]

If it only needs minor damping maybe Plastidip would work? They make it in white and it's fully removeable without leaving any trace behind. Amazing stuff really..

Plasti Dip Protective Coating Products | Plasti Dip Protective Coating Products | Rubber Dip Coating

I've been going crazy with this stuff lately so it just happened to be on my mind.

 

[bear]

You can try it, but do it outside, it is (or was ) solvent based... I think it is too light and thin to be very effective. better than nothing though.

_-_-bear

 

[bear]

you could also use the aluminum horn as a mold... use a non resonant material to build with?

 

[SQfreak]

The roofing stuff won't stick for very long and stinks to high heaven. SecondSkin would be perfect and one strip on front to back 1"-2" wide should be enough. Sound Deadening Materials for Noise Reduction | Second Skin Audio You could use Dynamat too if you want to buy local.

 

[djn]

you could also use the aluminum horn as a mold... use a non resonant material to build with?

Like concrete??? I almost did that with my 350hz round wood horns.

 

[djn]

If it only needs minor damping maybe Plastidip would work? They make it in white and it's fully removeable without leaving any trace behind. Amazing stuff really..

Plasti Dip Protective Coating Products | Plasti Dip Protective Coating Products | Rubber Dip Coating

I've been going crazy with this stuff lately so it just happened to be on my mind.

I think you are on to something. Never thought about using that to dampen anything, just coat my tools. Great idea.

 

[fpitas]

My experience with the 511s was that rubbery coatings didn't damp as well as harder coatings (like the stuff at the link I posted). Of course, the OP's horn may not need as much damping. Those 511s rang like bells.

 

[FrankWW]

Why don't you experiment with Plasticine (soft modeling clay that never dries out) or it's equivalent. It damps like crazy, doesn't smell, and never seems to dry out. It comes in all sorts of colours.

You might find you don't need to use very much. Find it at art or school supply stores.

Plasticine - Wikipedia, the free encyclopedia

 

[Charles Darwin]

Something like this stuff might work:

Everbuild 90805 Everproof DPM 908 5L: Amazon.co.uk: DIY & Tools

It's a water-based, odourless rubber-enriched bitumen paint and can also be used to bond foam or other damping (or is it 'dampening' in this case?) material to the horn.
Not sure how well it sticks to aluminium though…

 

[Charcoal]

make an outer box for the horn and fill with sand.

 

[ARIYAHOOR]

thanks to all replies...
making sand box is the smartest thing to do but will weight as earth 😛
Plasticine is not as sticky as I need... won't be there after some minutes... maybe our productions are nonstandard 😀
I'll try double side tap and bitumen...
looking for other ideas 🙄

 

[MrSlim]

This might be an option for you : Sonic Barrier Lightweight Vinyl Sound Damping Sheet 10" x 13 268-030
or something else here: SOUND DAMPING from Parts Express ship same day and come with 45 day money back guarantee. Free Shipping Available. Order free 10,000 product catalog.

I've used something like this: Cascade V-MAXMP Aluminum Damping Sheets 2.8 sq. ft. 268-287 before, and I think it would probably be more effective than a single layer product since there is a greater damping effect as the vibrations encounter the boundaries between layers of differing densities..

 

[MrSlim]

Or just forget about at Ringing Metal Horn and go with something that is totally non resonant.. 😀

The Paper Horn by Inlow Sound - The Paper Horn by Inlow Sound

 

[Cal Weldon]

also possible is the stuff used for roofing - it is a thick rubberized/bitumen sheet with adhesive on one side. Usually sold for "ice & water" - for example around skylights. Very heavy and dead.

Hi , roofing guy here. 🙂
Bear this is not really a practical product. It has too much memory and is dirty to work with. The only one I can think of is the sanded top surface but it still has too much memory.

Some is heat applied, some is self stick.

Different products. The peel and stick one is the most practical but I wouldn't use it on my horns and I get it for free.

I'd make strips and run them from the rear to the front. Or else make a long thin strip or two with a knife and wrap the horn in a spiral from throat out... you can likely do the entire horn that way...

The lip of the horn is the most important. What you do after that may or may not make a noticeable improvement.

The roofing stuff won't stick for very long and stinks to high heaven.

Smells like money to me. 😀 If you do the surface prep and use the right primer it will stick for longer than you know what to a babies blanket.

Why don't you experiment with Plasticine (soft modeling clay that never dries out) or it's equivalent. It damps like crazy, doesn't smell, and never seems to dry out.
You might find you don't need to use very much. Find it at art or school supply stores.

I would recommend Duct Seal. Better adhesion and great damping properties. It's what's applied to my horns.

I'll try double side tap and bitumen...
looking for other ideas 🙄

I think duct seal is your best option. Nothing better for the ease of use, long term durability and effectiveness. Try doing only the lips to begin with. That's where the resonance is transfered from the horn to the air. AFAIK it's the only part of the horn that actually gets excited to any real extent. It's the onlt part of the structure that isn't otherwise supported (read damped) in some way.

I have done many tests with both program material and rap testing.