EVA foam for performance speaker enclosures

[jeshi]

I think I found a project to use my EVA panels.

I've been wanting to make a portable "boominator". I think the EVA panels will be interesting as they would sustain the bumps and bruises of a portable system, as jeshi's says his small desktops can be tossed across the room with no damage.

Should be fun!

That's a good idea! The EVA is very damage proof, but of course the speaker drivers don't really like to be thrown around But it should still make an excellent robust and light weight portable speaker.

I have also been thinking about making a little boom-box speaker: maybe even explore the idea of a passive crossover mini-FAST. Maybe something like a pair of SB65 (or TEBM46 or fe83en) about 30cm apart with a 4" 5" or 6" woofer in the center to give a mono (summed) bass signal) Something I could power with a single TPA3116 amp running on batteries. Just a half-finished design idea bouncing around my head.
Just not convinced yet if it would be better than just using a pair of TC9 or TG9 in the same boombox idea.

 

[perceval]

I think I will start with just a couple of 3inchers, my idea was to try and incorporate a MLTL "a la TABAQ" but I'm afraid that would make the box way too big.

So, maybe just a vented design, I'll have to fire up WinISD and find out.

 

[BYRTT]

.....as jeshi's says his small desktops....

"she"

 

[perceval]

Terribly sorry... my bad.

Not many involved in speakers and DIY.

Apologies, Jeshi.

BTW, I love Japan! I'm presently just south of you, in Taiwan. Not a bad place either!

 

[jeshi]

Terribly sorry... my bad.

Not many involved in speakers and DIY.

Apologies, Jeshi.

BTW, I love Japan! I'm presently just south of you, in Taiwan. Not a bad place either!

no worries. I am used to this since I am a programmer/software engineer by day and a DJ/composer/producer by night (both male dominated fields). Also when I get into engineering mode, I get kind of tom-boyish anyways
My best friend here in Japan is Taiwanese and I really want to visit Taiwan soon.

 

[perceval]

Quite the busy one! Cool!
I dabble in music as well... nothing serious, mostly for fun.

Well, not to rush you, but fall is the best time!

October is usually not so hot in the evening, and still good weather all around.
I couldn't bear the big cities here (I'm from Canada and need space!) so i relocated to the east coast, in Hualien. Green mountains, and blue Pacific.

If you do come over one day, We could show you around the east coast a bit! Maybe some surfing? (that's my other passion)

More relevant info, it looks like WinISD suggests a 12-litre box for two 3" drivers I have. not too big, that's nice!

 

[perceval]

Here's a rough sketch of what I'm planning to do.

Drivers are 3". WinISD comes up with 6 litres for each chambers, which will be sealed separately. 1x10cm. 9cm long for 65Hz.

That should be about 20"x6"x6".

Baffle is doubled, drivers will be sandwiched in between. I'll also put a TPA3116D2 50w amp there, with a 3.5mm plugin.
There will be some bracing, no shown in the drawing.

Will probably need BSC. Getting parts for it will be the challenge!

 

[BYRTT]

.....Let's see how the 10f/8424 compares -- if it ever arrives (I am still waiting for europe-audio to ship my 10f/8424, they don't return my emails, so I am starting to get worried they might have taken my money and I will not get the speakers. ).....

Noticed over comparison thread they arrived hope cost and trouble was worth it and they back as very good performers.

 

[jeshi]

Noticed over comparison thread they arrived hope cost and trouble was worth it and they back as very good performers.

Yes the 10f/8424 finally arrived, actually just today. Placed the order on July 25th and arrived on Sept 7th. sigh... That is the last time I order drivers from EuropeAudio. They never once returned my emails. And it seems like they misplaced my order at least twice. And then they forgot to actually ship it after issuing the invoice, changing the status on their website and even setting up a FedEx tracking label. But someone then forgot to put it in a box and hand it to FedEx. Maybe they are nice people, but they really don't know how to run a business.

Sorry been really busy the last couple weeks so haven't had much time for proper building and testing. I did manage to build a new baffle for the SB65 and Satori and did some initial listening and measurements. I will do the same with the 10f/8424.

I can at least share some photo to tease you The finishing is a bit rough, but I did countersink both the Satori and the SB65

The 10/8424 in the sealed box with just a quick-and-dirty piece of scrap EVA (not flush mounted) press-fit adapter just to get a first impression. And I DO LIKE IT

 

[xrk971]

Nice! That SB65 looks just like a 1in aluminum dome tweeter! Do you have any measured XO plots for the SB65/Satori combo?

10F/8424 looks perfectly at home there.

 

[jeshi]

Nice! That SB65 looks just like a 1in aluminum dome tweeter! Do you have any measured XO plots for the SB65/Satori combo?

10F/8424 looks perfectly at home there.

Yes I do have some plots but it is a bit complicated which I why I was trying to hold of a bit. The problem is that the Satori is so good that it is showing some of the limits of the SB65. But ok twist my arm, here are some

Measurements are at 25cm but I don't know the actual SPL level, something around my normal listening level. I was trying all sorts of crossovers from LR2 to Harsch and at many points (350hz, 450hz, 500hz, 700hz, 800hz, 900hz). I was changing XO and then listening to music and change, repeat....

At the end of that round I decided that the 700hz to 900hz sounded the best and gave the best measurements and I preferred the LR2 to the Harsch. But the SB65 seemed to have less dynamics than the RS28f dome tweeter. So even though it worked and produced a clean, high quality sound, it just could not quite reach to the level of the RS28f/satori.

Here is the LR2 700hz XO which is about the best I could get

Here is LR2 350hz and you can see how much lower distortion the Satori is compared to the SB5. The distortion in the 350-700hz range is now higher than when the satori covered it.

And here is the previous RS28f Satori at maybe around the same SPL (maybe)

And at a MUCH louder level (90db at 0.5m)

Haven't given up on the SB65 but they might be better served in lower SPL application. Or maybe a small line-array pair of SB65 per channel would give enough headroom. But at $35 each 2x per speaker doesn't really make much sense.

 

[BYRTT]

.....The 10/8424 in the sealed box with just a quick-and-dirty piece of scrap EVA (not flush mounted) press-fit adapter just to get a first impression. And I DO LIKE IT

Great you like it and this actual mean a lot because i active was in a group to recommend it over comparison thread second round and this driver is a expensive part. Thanks the teasers sounds as your RS28f/satori is very very good and hard to beat, have best investigations.


Sorry had a typo in previous post so quote myself below, before word "back" i forgot "pay" : )

Noticed over comparison thread they arrived hope cost and trouble was worth it and they back as very good performers.

 

[jeshi]

One idea I have for the SB65 is in a boombox style speaker. I am working up a slot-loaded-open-baffle 8" driver pair right now. A modified version of Nelson Pass's design. And I am thinking about using a single SLOB in the center to do a mono-summed-bass for the two channels and then an SB65 (or other small 2" driver) on either side to give the stereo in one box. This would give the SPL benefit of two SB65 drivers but also give a boombox style stereo effect. And a boombox can get away with more distortion than a "studio monitor". Might work really well for playing portable music at picnics, beaches....

 

[xrk971]

Yes I do have some plots but it is a bit complicated which I why I was trying to hold of a bit. The problem is that the Satori is so good that it is showing some of the limits of the SB65. But ok twist my arm, here are some

Measurements are at 25cm but I don't know the actual SPL level, something around my normal listening level. I was trying all sorts of crossovers from LR2 to Harsch and at many points (350hz, 450hz, 500hz, 700hz, 800hz, 900hz). I was changing XO and then listening to music and change, repeat....

At the end of that round I decided that the 700hz to 900hz sounded the best and gave the best measurements and I preferred the LR2 to the Harsch. But the SB65 seemed to have less dynamics than the RS28f dome tweeter. So even though it worked and produced a clean, high quality sound, it just could not quite reach to the level of the RS28f/satori.

Here is the LR2 700hz XO which is about the best I could get

Here is LR2 350hz and you can see how much lower distortion the Satori is compared to the SB5. The distortion in the 350-700hz range is now higher than when the satori covered it.

And here is the previous RS28f Satori at maybe around the same SPL (maybe)

And at a MUCH louder level (90db at 0.5m)

Haven't given up on the SB65 but they might be better served in lower SPL application. Or maybe a small line-array pair of SB65 per channel would give enough headroom. But at $35 each 2x per speaker doesn't really make much sense.

Jeshi,
These look pretty nice. Do you have plots showing the LF + HF + Combined traces all overlaid? Not a big deal if you don't have it - don't retake data just for me. Your rounded rhomboid cabinet seems to have done a good job controlling edge diffraction.

 

[jeshi]

XRK, I don't have those measurements. These measurements were just part of an exploration session and unfortunately at the end I decided I really didn't want to pursue the SB65/Satori too much further. This combination has a nice flat FR and does sound pretty nice, but it doesn't have the dynamics nor the transparency of the RS28f/Satori combination. The RS28f/Satori just has this wow level of clarity and transparency.

The only other measurements I have are the raw drivers before crossover to help me get a feeling for how they will blend. The satori has only the Linkwitz transform applied. It shows me where the Satori HD starts to rise and where it starts to get some breakup peaks. These are at 25cm but unknown DB and they are level matched. Basically the drivers as they are ready for XO but without XO.

Not sure what is happening with the extra distortion in the satori in the 500-1500hz range. My guess is that the two drivers are in the same box, the SB65 is not isolated in a separate sub-enclosure and I guess that the satori is causing resonance in the SB65. I don't see this with the RS28f/Satori combo. If I would want to go further I would need to build this sub-enclosure. But his would only improve the HD, it wouldn't improve the dynamics problem. And with a 700hz XO I am kind of avoiding this trouble region. Yes I know this is not the best-practice build, but I just wanted to explore.

Maybe I can copy your dagger arrangement and make a special test-baffle to allow me to test many different fullrange drivers with the satori. But I would kind of rather build my SLOB woofer for fullrange testing and leave my satori for the RS28f. Let' see how much time and energy I have for this side of exploration

Oh one thing that is interesting is that this mix-box enclosure allows the satori to act a little like a passive radiator when only the SB65 is driving. I am getting down to 80hz with just the SB65 and not so bad HD. That might actually be an interesting way to use the SB65 (in a box with a passive radiator)...hmmm...maybe something like this https://www.madisoundspeakerstore.com/approx-5-woofers/peerless-830880-peerless-5.25-mini-passive-radiator/

 

[xrk971]

Satori as passive radiator LOL.

Definitely need their own chambers of you want to get that distortion lower.

 

[jeshi]

Yeah I know isolated chambers is the correct way, I was just cutting corners. (and I was curious to see for myself how mixing drivers in the same box really effects things)
I might just do two box testing for awhile. A little like how you did things in your round3 with the fullrange in your nutiloss on top of your RS225 box. I can use my little sealed box for the fullrange and set on top of the satori all alone in its sealed box.

 

[jeshi]

here is my first measurement of the 10f/8424 in the sealed EVA box at 25cm 93db. This is about my normal listening level (but of course I don't listen that close to the speaker).

and here is with a simple low shelf at 900hz +5db q0.7. SPL meter read ~94.5db after this correction.

and the inverse, a high shelf at 900hz -5db q0.7 (SPL meter read 90db after this correction)

This driver is SO easy to work with! Really doesn't need any EQ correction (just a baffle-step-correction or LT) and it sounds very clean and detailed. This one really might be able to go head to head with the rs28f/satori (just first impression crush though)...but let's see after I live with them for awhile

 

[jeshi]

by the way this is louder than the level I was running the SB65 at and it is showing lower distortion and is much more dynamic and punchy. And the 10f still has a lot of headroom on the amplifier. The SB65 was running at almost full power on my TPA3116 while the 10f/8424 is running at -12db input gain to get to this SPL. OK I am impressed.

 

[jeshi]

OK one more 10f/8424 EQ.
Low shelf 160hz +6db q0.7
high shelf 900hz -5db q0.7
LR48 HP 60hz for protection
I really think stretching this to 80hz is about the max I feel comfortable with.

WOW this sounds so good!!!!! Listening to some deephouse club music (this track) which a full range should not do well, and it is sounding correct (no problems) and it is punchy, groovy, and super clean. This might become my driver for this sealed box