EVA foam for performance speaker enclosures

[perceval]

Mattes,

thanks for sharing. Take your time, we are not going anywhere!
I'm sure I won't be the only one waiting for your next post.

You have a truly unique setup, with that Fertin driver, the 5-petal diffraction foam baffle, and I can't wait to see what will be underneath for bass duty.
Form follows function, yes, but with that kind of flair, it makes it quite unique, just like wesayso's Towers.

I surely hope you have a mic and will be able to share measurements and the benefits of the design.

PS. satellite internet? Out of grid reach in Germany? That must be quite outside and very rural!

 

[jeshi]

Mattes,
I am happy for you to post here. It's an old thread now and I am so happy to hear that others like you and chebum have been inspired to also play with EVA foam speakers. I love your flower petal design and I think these are the types of round-smooth designs that can really take advantage of the EVA foam. When you start your new thread, please also make a post here with a link to it.


The recent activity here has me thinking about revisiting a vented design I had drawn up and simed but never built. I've built my Satori MW16P / Dayton RS28f 2way both sealed and open-baffle but never tried ported. I also picked up some SB Acoustics SB29RDCN tweeters awhile back and never got around to trying a build with them.

 

[Mattes]

Hi Jeshi,

OK, i will post a link soon. Building this petal design was a small nightmare in EVA (I´ve made a total of 5 of the small ones for the fullrange, only the last 2 ones were really nice, and the bass flowers are a big nightmare and not finished yet... details in the thread), but would have been worse in wood, and most probably not working that good.

Perceval, I´m currently at work and away from home, sadly. I´m a seaman by profession and have therefore to rely on satellites, no fibreoptic cables ´round here...

All the best

Mattes

 

[mushroommunk]

Jeshi and XRK,

Question for you two. Due to my girlfriend moving in my living room speaker design is having to change. (Does two large shelves of stuffed animals work as a bass trap?) Before I settle on the final design I want to play around with XPS and EVA, plus winter is coming so what better time?

I'm thinking if I end up with something I like, I'm not going to want to redo it in wood. Have either of you done anything with veneering your foam stuff? Or plastidip? I saw Jeshi painted one of her enclosures but I don't recall seeing much beyond that. Nor much over in the foamcore thread (though I haven't read literally everything there...yet).

I'm also thinking about the effect of laminating 1/8" hardboard either between two foam layers, or two hardboard layers, one on each side of the foam. I'm thinking similar to how Ikea does their boards, only foam instead of cardboard.

I've already got the Tang Band W3-2141 I'll be using to play around with so might have some pictures next week.

 

[xrk971]

A wall of stuffed animals helps and can't hurt, but to the extent of how well it works for bass frequencies - maybe not as effective as it would be mids and highs. As far as I know, bass traps need to be large (several meters long) acoustic cavity traps to capture the long waves. Stuffed animals on a shelf are more like foam padding or blankets/curtains in a room. This is for mids and highs mostly.

I have put 3/16in floor underlayment ply (Luaun or mahogany plywood) on a foam core panel as the K-aperture for an XKi and it worked well. It looked nice and gave it some stiffness and provided damping on back side. Similarly, I added same 3/16in ply to the front baffle of my 10F/RS225 FAST speaker with XPS foam core main panel. That worked very well and gave a nice surface to hang am 8in driver from. Typically bonded together with construction adhesive like low VOC Liquid Nails or latex caulking.

The Daytonator - PA130-8X

10F/8424 & RS225-8 FAST Ref Monitor

 

[mushroommunk]

A wall of stuffed animals helps and can't hurt, but to the extent of how well it works for bass frequencies - maybe not as effective as it would be mids and highs. As far as I know, bass traps need to be large (several meters long) acoustic cavity traps to capture the long waves. Stuffed animals on a shelf are more like foam padding or blankets/curtains in a room. This is for mids and highs mostly.

I have put 3/16in floor underlayment ply (Luaun or mahogany plywood) on a foam core panel as the K-aperture for an XKi and it worked well. It looked nice and gave it some stiffness and provided damping on back side. Similarly, I added same 3/16in ply to the front baffle of my 10F/RS225 FAST speaker with XPS foam core main panel. That worked very well and gave a nice surface to hang am 8in driver from. Typically bonded together with construction adhesive like low VOC Liquid Nails or latex caulking.

The Daytonator - PA130-8X

10F/8424 & RS225-8 FAST Ref Monitor

Haha, I was mostly joking on the stuffed animals. Room acoustics is the area I'm stronger. Now you've got me curious as some of them are legit the human sized stuffed bears and things, so volume is actually there.

That sureply is one of the things I was looking at grabbing last time I was at home depot, good to know it works. Wait a second...I've got xps at home, I've got liquid nails, and girlfriend is out tonight. Guess I'm going to get building.

 

[jeshi]

Jeshi and XRK,

Question for you two. Due to my girlfriend moving in my living room speaker design is having to change. (Does two large shelves of stuffed animals work as a bass trap?) Before I settle on the final design I want to play around with XPS and EVA, plus winter is coming so what better time?

I'm thinking if I end up with something I like, I'm not going to want to redo it in wood. Have either of you done anything with veneering your foam stuff? Or plastidip? I saw Jeshi painted one of her enclosures but I don't recall seeing much beyond that. Nor much over in the foamcore thread (though I haven't read literally everything there...yet).

I'm also thinking about the effect of laminating 1/8" hardboard either between two foam layers, or two hardboard layers, one on each side of the foam. I'm thinking similar to how Ikea does their boards, only foam instead of cardboard.

I've already got the Tang Band W3-2141 I'll be using to play around with so might have some pictures next week.

Hi mushroommonk,
I agree with XRK that the stuffed animals will help but more for reflections and imaging (mids and highs) rather than bass. I have found that the more stuff I have in my living room (listening room) like book shelves, paintings, furniture, that these things naturally create sound dampening and can really improve the acoustics of a room. I never quite understand why so many people like a clean boxy listening room.

I did try the painted EVA and I have to admit that I felt like it sounded better before I painted it. I also really love the clean white look of the EVA foam that I get here in Japan. So right now I keep all my EVA speakers in the natural white. To me it creates a very nice look of black drivers with white speaker (especially keeping the front panel white EVA). I also like the more rounded organic shapes I can create with the bendy EVA compared to the rigid XPS. So granted I am a single data-point female but maybe see if your girlfriend would prefer white speakers to wood covered speakers. I definitely prefer white speakers.

Unfortunately my cat has decide my EVA speakers make excellent scratching posts so they don't look like they used to. But maybe this is making them sound better adding some random diffusion

 

[turk 182]

oh i can see it now, an emerging market.... cat distressed EVA speakers (will the ones distressed by Persians be more highly prized?)

 

[jeshi]

oh i can see it now, an emerging market.... cat distressed EVA speakers (will the ones distressed by Persians be more highly prized?)

lol well if the self-destructed Banksy girl with the red balloon is any indication then maybe the world does add value for "properly" destroyed art.

ps: I hope everyone realized I was joking about the destructed speakers sounding better. I honestly don't know. Luckily he hasn't touched the front of the speaker where I think the most effect of diffraction/diffusion happens.

 

[mushroommunk]

...Unfortunately my cat has decide my EVA speakers make excellent scratching posts so they don't look like they used to. But maybe this is making them sound better adding some random diffusion

I have two cats, so I'll have to keep in mind that cats like EVA.

 

[ewollowe]

Yup, cats love that stuff.

I'm hoping they're not as fond of polystyrene as I've thrown together a couple boxes for fun.

 

[Mattes]

Dear all,

I would be very sad if my baffles look like Jeshi´s enclosures... too much work and money spent. I´m happy that my daughter is old enough to know to NEVER EVER TOUCH daddy´s loudspeakers...

Mushroommunk, like Jeshi I prefer the tactile and visual sensation of the (unscratched) finely sanded EVA foam (mine is 125 kg/m³, the density of the material definitely plays a role in these applications), she prefers hers in white, I prefer black. Even my wife likes the tactile properties of the finely sanded material a lot. It´s like suede, very smooth.
I´m also conform with Jeshi insofar as I prefer the non-painted surface to anything else, have tried this a few iterations before, and prefer the sonics of the unpainted material. Perhaps a matter of surface roughness and reflection properties?

One has to think about which glue to use, not only from a technical standpoint, but also with regard to appearance, if the glue seams are visible. I choose epoxy with black colour pigments and microballons, in order to create seams with the least visual impact. The seams are still visible, but not from listening distance.

All the best

Mattes

 

[ewollowe]

I´m also conform with Jeshi insofar as I prefer the non-painted surface to anything else, have tried this a few iterations before, and prefer the sonics of the unpainted material. Perhaps a matter of surface roughness and reflection properties?



Mattes

It could be as you say but I also wonder if the paint is adding enough mass to the enclosure that energy storage is increased?
I'm considering lining my poly foam enclosures with eva foam to give me a certain replication of the harbeth lossy design.

 

[jeshi]

One has to think about which glue to use, not only from a technical standpoint, but also with regard to appearance, if the glue seams are visible. I choose epoxy with black colour pigments and microballons, in order to create seams with the least visual impact. The seams are still visible, but not from listening distance.

Hi Mattes
really glad to hear you feel the same way about the unpainted EVA (visual, tactile, and sonics). Where did you find your black 125kg/m3 EVA? I would love to try that material if possible. I also love your idea of epoxy with pigment and microballoons. You have really taken this to the next level. Thank you!!
I'm working on an EVA vented box right now for my SB-satori 2way but it's a rough first attempt so I built it from some scraps left around. But if I like it, I will make a nicer looking second version and I will try your idea of epoxy with white pigment and maybe try to find microballoons. But I might also try PVA white glue (like elmers). The contact cement I use makes excellent bonds and I suspect the rubber-like glue might add another vibration absorption layer to the enclosure, but it is yellow and as much as I try, it still sneaks out in places on the seams for less than perfect looks.

Mattes your speakers look amazing so I would also be sad if I had put so much effort into that level of perfection and my cat destroyed it. At some point I am going to replace my destroyed enclosure. Just waiting to see if I like the vented version more than the sealed version.
cheers jeshi

 

[Mattes]

Hi Jeshi,

thanks for your kind words. I got the foam from Intec Foams in the UK, special order in 40 mm thickness...
The constrained layer effect of rubber glue is surely positive. I tried Sikaflex as well, but it doesn´t work. In these large surface bonds, I found it necessary to work with a jig and some pressure applied.

Ewollowe, the mass of paint I applied was minimal, I´m pretty sure it hasn´t changed the resonance behaviour a lot. Maybe a case of different surface properties? I´m not sure, and I will never be, as I won´t go in this direction anymore...
However, I´m quite sure that a smooth and relatively soft surface will not do any harm to my music.

All the best

Mattes

 

[xrk971]

Unfortunately my cat has decide my EVA speakers make excellent scratching posts so they don't look like they used to. But maybe this is making them sound better adding some random diffusion

Ouch! Good thing she did not touch the Satori cone or surround. Maybe you need to make a sacrificial EVA post - shaped like a speaker as the decoy? I found that just taping clear packaging tape over an area frequented by claws makes it smooth and unattractive for purposes of sharpening claws. My 21yr old cat passed away recently, his 18yr old brother is still around, completely blind but gets by very well based on good memory, and sense of touch and smell. Both are so old they stopped sharpening their claws so they had to be clipped regularly else grow as a curved blade into their foot pads.

Maybe a thin hardwood veneer on the sides and backs may reduce the scratching and make it look more like a conventional wood speaker. I admit the white EVA looks great though.

 

[jeshi]

Ouch! Good thing she did not touch the Satori cone or surround. Maybe you need to make a sacrificial EVA post - shaped like a speaker as the decoy? I found that just taping clear packaging tape over an area frequented by claws makes it smooth and unattractive for purposes of sharpening claws. My 21yr old cat passed away recently, his 18yr old brother is still around, completely blind but gets by very well based on good memory, and sense of touch and smell. Both are so old they stopped sharpening their claws so they had to be clipped regularly else grow as a curved blade into their foot pads

He seems to only scratch it to get my attention when I am too focused on the computer/movie/project and he knows that if he scratches the side of the speaker I stop what I am doing and freak out and scream stop, but he gets my attention. Unfortunately this has gone on over a year now and you see the result of this. I honestly feel we are stuck in this pattern and all I can do is either cover the side (like you say) or just accept that I will need to rebuild the left speaker about once a year. But you are right, I am so glad he has focused on the back side of the speaker rather than the front with the drivers and the foam. I bought some metal grills to protect the fronts and still need to install them. Will add them when I make the new vented box. But I don't think it will look as nice with the metal grill and it might alter the sound. So difficult decision.

so sorry to hear about your cat. my cat Bonkers was 21 when he died about 2 years ago. New cat Sora has been with me a year now and he is the speaker destroyer.

 

[mushroommunk]

He seems to only scratch it to get my attention when I am too focused on the computer/movie/project and he knows that if he scratches the side of the speaker I stop what I am doing and freak out and scream stop, but he gets my attention. Unfortunately this has gone on over a year now and you see the result of this. I honestly feel we are stuck in this pattern and all I can do is either cover the side (like you say) or just accept that I will need to rebuild the left speaker about once a year. But you are right, I am so glad he has focused on the back side of the speaker rather than the front with the drivers and the foam. I bought some metal grills to protect the fronts and still need to install them. Will add them when I make the new vented box.

so sorry to hear about your cat. my cat Bonkers was 21 when he died about 2 years ago. New cat Sora has been with me a year now and he is the speaker destroyer.

Two things that really help with this in my experience. First is to put some sort of scratching post near the targeted item. They scratch it instead of the item. The second is to have a routine of actually playing with the cat. 10 to 15 minutes a day. It really fulfills their hunter instinct and they're way less needy.

 

[ewollowe]

Two things that really help with this in my experience. First is to put some sort of scratching post near the targeted item. They scratch it instead of the item. The second is to have a routine of actually playing with the cat. 10 to 15 minutes a day. It really fulfills their hunter instinct and they're way less needy.

Interesting that you should say that because that just happens to be my routine.

 

[perceval]

Has anyone tried ink instead of paint?

The porous nature of the EVA might be ok, or maybe absorbs too quickly?

Ink wouldn't alter physical characteristics of EVA, and is surely very easy to get by in Japan!
I can find ink in any little stores here.

Had two cats back in Canada. One got to 24. He was still catching birds and no dogs would dare come close to our house., even though he had no front claws (done by the first owner) and his canines fell off at about 22. He was the sweetest with humans. Really mellow.

My current cat is 15. I got her when she was a baby still. Someone drove by and tossed the kitten on the road. A local shop picked it up, and when I passed by, she came and curled up to me. She chose me, not the other way around. Had to keep her.

She was so young, when we got home, she tried to scratch the couch once. I showed her I was angry, and she understood the couch was off limits. I made two small wooden furniture with soft bare wood. She tried to scratch them, while looking at me. I told her ok. She now only uses those two for scratching. She's been a good cat.