Is all speaker fill created equal?

[badspeakerdesigner]

As much as I’d love to use these solutions, I think my best route will be to use standard fiberglass home insulation. All these solutions are very good, but also costly, so I think gloves and a mask are gonna be my best bet.

Atleast in regards to this project, would love to try the other solutions, but thank you all for your suggestions and I’d love to continue to learn more so if you have more resources or seek to discuss or ask more on the subject, let’s definitely keep this thread open and going

the cotton batting at ats can be bought individually. I got two for $50 and that covered two ATC SCM100 sized big speakers inside. Ain't goin back to fibreglass.

 

[AlfaNovember]

Melamine erasers glued into the cabinet with Pliobond contact cement:

 

[sam_adams]

Doesn't really work with the melamine erasers I was referring to.

Melamine foam is very expensive stuff. Why? I don't know—since melamine itself seems to be cheap enough to be put into food products by some foreign manufacturers. You've probably seen the prices on the sites from many of the acoustic panel vendors that carry it and it is ridiculous compared to more traditional products. The little bits that they cut it into for those Mr. Kleen Magic Erasers or similar make them impractical for large enclosures. With the panel-sized pieces, it would make me cry a bit to cut them down to small sizes to fit in an enclosure.

 

[ppataki]

I would have a dummy question re. melamine foam: shall it be considered as an alternative to other filling materials like wad? Or shall it be considered as an alternative to felt that is applied on the internal walls?

I usually apply three things inside a cabinet: 4mm vibrodamping sheet (to make the cabinet more stiff and for sound absorption) then 16mm felt (also for absorption) and then wad filling (to make the driver 'see' the cabinet bigger)

Like this:

So if I wanted to use melamine, would that replace which component?

Thank you

 

[MCH]

Melamine foam is very expensive stuff. Why? I don't know—since melamine itself seems to be cheap enough to be put into food products by some foreign manufacturers. You've probably seen the prices on the sites from many of the acoustic panel vendors that carry it and it is ridiculous compared to more traditional products. The little bits that they cut it into for those Mr. Kleen Magic Erasers or similar make them impractical for large enclosures. With the panel-sized pieces, it would make me cry a bit to cut them down to small sizes to fit in an enclosure.

There is no reason for melamine foams to more expensive than other foams unless these particular grades are somehow difficult to make.
Question for you. Do you know if other open cell melamine foams like basf's basotect would do the job? It comes in big panels (no need to glue small pieces) and not being ultra cheap, the amount you need to fill in a speaker it should not be prohibitive

Basotect® (MF)

Sound absorption, fire resistance, thermal insulation or abrasiveness: Basotect® combines many requirements for a high-performance foam in one product. In the construction, automotive and transport sectors, but also in consumer applications, Basotect® provides a great variety of options.

plastics-rubber.basf.com

 

[hex168]

I wish I had a better memory. Somewhere there is a post on Ultratouch recycled denim insulation. Supposed to be excellent for box fill.

 

[fpitas]

I wish I had a better memory. Somewhere there is a post on Ultratouch recycled denim insulation. Supposed to be excellent for box fill.

i used a similar product available in panels;

ATS Recycled Cotton Batts

Buy ATS Acoustical Cotton Batts, 2 inch, Single Piece online at ATSAcoustics.com. Order Single Pieces on this page. ATS Recycled Cotton Batts are an eco-friendly alternative to fiberglass or mineral wool acoustic insulation. The natural cotton fibers are 100% recyclable and are made from at...

www.atsacoustics.com

Selecting the Right Acoustic Material

acoustic panels

www.atsacoustics.com

 

[SMJ]

I would avoid fibreglass insulation material if you can. With age the fibres start to break up and find their way into the air gap between the loudspeaker coil and the magnet causing all sorts of problems.

If you must use fibreglass encase it in a pouch of material such as nylon tights/pantyhose to catch most of fibres.

 

[IPunchCholla]

Are there any good readings on speaker fills? I have played with variations and often there was no audible difference in the sound and the few measurements I have made have shown very little difference (within measurement variation) in the materials I’ve used.

 

[fpitas]

Are there any good readings on speaker fills? I have played with variations and often there was no audible difference in the sound and the few measurements I have made have shown very little difference (within measurement variation) in the materials I’ve used.

Vance Dickason's Loudspeaker Design Cookbook at least used to have a lot of measurements.

 

[IPunchCholla]

Vance Dickason's Loudspeaker Design Cookbook at least used to have a lot of measurements.

Thank you! After looking at the measurements they seem to be close enough (1.5 dB max difference for 0 to 100% fill) that my not hearing a difference is reasonable. I didn’t see any reference to repeatability of the measurements or their variation. I am also struck by the phrase that “It is a well known fact” that fibrous fill does these things, with a single reference to a 1976 paper in JAES (which of course, my university libraries don’t subscribe to (only two libraries in all of OCLC do?) so it might take a bit of time to check up on.

 

[Wolf]

Frost King recycled cotton denim batting from Amazon is just like Ultratouch/BondedLogic/EcoCore products, but layers aren't as thick.
I like the stuff a lot!

If you can get 100% wool batting, it is as good if not better than the Ultratouch products.

 

[silverD]

We receive packages that use recycled denim for insulation. I keep these for future speaker projects:

 

[egellings]

I used a material called Acoustastuff (sp?), which as a polyester material. What was different about it was that the individual threads of the material were kinked, rather than a straight fine wire shape. The extra friction caused by the kinked fibers rubbing together with the sound produced more damping effect.

 

[sam_adams]

There is no reason for melamine foams to more expensive than other foams unless these particular grades are somehow difficult to make.
Question for you. Do you know if other open cell melamine foams like basf's basotect would do the job? It comes in big panels (no need to glue small pieces) and not being ultra cheap, the amount you need to fill in a speaker it should not be prohibitive

Basotect® (MF)

Sound absorption, fire resistance, thermal insulation or abrasiveness: Basotect® combines many requirements for a high-performance foam in one product. In the construction, automotive and transport sectors, but also in consumer applications, Basotect® provides a great variety of options.

plastics-rubber.basf.com

I believe that BASF is the world's largest supplier of melamine foam products, but not all melamine foam product is sourced from them. Acoustical Solutions' Alphasorb Flat Acoustic Foam is supplied in different thicknesses and two sizes. It is not sold by the sheet or piece, only by the box of the same size and thickness. Therefore, it is quite a sizable outlay if you are only doing a couple of speaker cabinets. By comparison to run-of-the-mill polyether foam, it's roughly three to four times as expensive.

 

[fpitas]

I used a material called Acoustastuff (sp?), which as a polyester material. What was different about it was that the individual threads of the material were kinked, rather than a straight fine wire shape. The extra friction caused by the kinked fibers rubbing together with the sound produced more damping effect.

Yes; in my mids i mixed that, cotton waste and open cell foam, based on Dickason's measurements.

 

[Severian]

For my latest projects, I purchased sheets of eggcrate open cell foam from a supplierr called The Foam Factory. Basic stuff, but the quality seems good. I'm cutting to fit and attaching with hot glue.

For my nicest speakers I've used rock wool batts stapled down with speaker grille cloth from PE, but this time I'm looking to save weight and mess.

I've also never been convinced that lining makes a huge difference.

 

[cavedriver]

what about the fiberglass material used in sound absorbent panels? Supposedly effective down to fairly low frequencies due to fiber density and fibers are somewhat bound together with a chemical process (but still a type of fiberglass):

Knauf Insulation - GIK Acoustics

Knauf Insulation Acoustical Smooth Board is made from inorganic glass mineral wool preformed into boards with ECOSE® Technology.

www.gikacoustics.com

 

[Wolf]

PE is now stocking their own Denim products....

Home

 

[kemmler3D]

I used to sell acoustic foam (Polyurethane stuff that I imported from China, The Foam Factory was one of my competitors at the time) ... IIRC Melamine is a lot cheaper than polyurethane, e.g. https://www.alibaba.com/product-det...915.html?spm=a2700.details.0.0.20a46ea1MTvFoD