DIY Flat Panel Speaker Love

[Gary.M]

Re: DIY Flat Panel Speaker Love

What you describe as EPS sounds just like low grade XPS (expanded polystyrene) For EPS (extruded polystyrene) look for good insulation material. That's one of its prime uses.

Sorry I got the EPS and xps backwards. What you want is extruded though. The manufacturing process produces the type of structural integrity we need.

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

Hey UBS!!
The EPS I had was in a 1'x4' sheet (.75" thick?), very course and the expanded poly pieces had a tendency to fall apart when you attempted to sand the edges. The surface was not flat... very mottled. Could not even sand it smoothly.

Sounds like the EPS you are using is good quality. I checked 2 Lowe's in the area and I've had no luck so will be looking to see if I can order on line and have it shipped to a local store... the EPS you have really sounds like a good material!

Could you snag a quick phone pic of your EPS? If I could take a peek at the material before ordering it,that would be excellent and very appreciated!

Thanks,
Rich

Your eps must of been different then mine as the Lowes I went to only carried the 4X8ft EPS and XPS panels. I am not really good with computers lol so if I have some time I will try to take pics and down load it to photobucket.

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

Sorry I got the EPS and xps backwards. What you want is extruded though. The manufacturing process produces the type of structural integrity we need.

I am no expert on eps or xps but from what I read and seen the standard XPS color is either blue or pink, while the standard eps is white.
Even at Lowes where I bought my eps from it was white and right next to it was the XPS and it was blue.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hey UBS... no worries on the pics. I assume this is the EPS board you used? 4x8 1" thick ????



I like XPS, don't get me wrong, it can really sound fantastic. But there is a coloration that I hope is reduced using a high quality EPS. EPS can be very light and strong... and the knuckle test (IIRC) will have less of a hollow sound. Appears to me to be less over damped than XPS.

Sedge over at AC preferred his quality EPS over XPS. The difference are likely small, but I want to try it and pick the best material for my framed build.

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

Hey UBS... no worries on the pics. I assume this is the EPS board you used? 4x8 1" thick ????

[ATTACH=CONFIG]63021[/ATTACH]

I like XPS, don't get me wrong, it can really sound fantastic. But there is a coloration that I hope is reduced using a high quality EPS. EPS can be very light and strong... and the knuckle test (IIRC) will have less of a hollow sound. Appears to me to be less over damped than XPS.

Sedge over at AC preferred his quality EPS over XPS. The difference are likely small, but I want to try it and pick the best material for my framed build.

Yup that is the one 1 inch 4X8 with the skin wrap on to protect the foam from damage.....From what I've notice the XPS is stiffer and heavier then the EPS. With the XPS being stiffer which is what I think produces that hollow sound. The EPS on the other hand is not as stiff and has less weight and has a more natural warmer tone then the XPS. What Ive also noticed is that the EPS bass seems to be more prominent due to it flexing more then the stiffer XPS.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Well, we want stiffness... panel stiffness is a good thing.

Since you have both materials, do a knuckle test... wrap your knuckles on the panels and listen to the sound(hopefully you have 2 panels the same size,etc.). XPS has a dull, somewhat hollow sound(best I can describe it). EPS, I imagine, has a bit higher pitched sound.

Do you have a means of measuring your panels? I'd be curious how XPS and your EPS measure. A more flimsy panel (all other parameters the same) will have less output the last octave. This based on my test 2x2 XPS panels where a panel with straight edges and corners is stiffer than the same panel with round corners and edges. Was abut a +2dB increase for the stiffer, non-rounded panel.

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

Well, we want stiffness... panel stiffness is a good thing.

Since you have both materials, do a knuckle test... wrap your knuckles on the panels and listen to the sound(hopefully you have 2 panels the same size,etc.). XPS has a dull, somewhat hollow sound(best I can describe it). EPS, I imagine, has a bit higher pitched sound.

Do you have a means of measuring your panels? I'd be curious how XPS and your EPS measure. A more flimsy panel (all other parameters the same) will have less output the last octave. This based on my test 2x2 XPS panels where a panel with straight edges and corners is stiffer than the same panel with round corners and edges. Was abut a +2dB increase for the stiffer, non-rounded panel.

Well, for me I am searching for the right degree of stiffness that sounds the best to me. Its like Goldie locks and the Three bears where one material is too stiff , while another material is too soft and then there is one material that is JUST RIGHT. lol

Yeah I did that knuckle test with both eps and xps panels being of the same size and the XPS has a more hollow solid hard type of knock due to it being stiffer while the EPS has a softer/duller knock due to it being less stiff.

No not really as I am more of an old school type of person as the only measuring tools I use for sound is my ears lol.

Experimented with something new instead of the glue/water mixture I just used plain old paint on the front side only while the back side where the exciter is uses the glue/water mixture. I also carved out the edges of the panels as you can see in the pic similar to the bertagni speakers....of course this is just a demo panel so the cuts are not even shaped or accurate lol.

[Crapflinger]

Re: DIY Flat Panel Speaker Love

I've successfully read all 33 pages of this thread in about 4 days.....believe me, not an easy thing to do. I commend all of you guys on your thoroughness. also, I'd like you to all know, that as a sound equipment outsider, you're all clearly insane (that's a compliment).

so, to jump in on the tail end of what is clearly a hard battle of testing....I've got some questions.

my plans are to build my brother a bit of an odd project. it started out being a programmable doorbell of sorts that would basically allow me to scream obscenities at him in his house any time someone came to his door and rang his doorbell. the original build went ok, but didn't quite have the best results (had trouble integrating into his wireless doorbell setup as well as lack luster volume from the setup). to that end, I decided to take the thing back and redo it with moar powar. I was going to use a 2x 20watt class D amplifier from ADA fruit to drive two 20 watt regular speakers...then I realized that a 40watt doorbell sounded ridiculous (though fun). so, the next idea was to make it a doorbell that is also a satellite stereo type system for his back room. which would allow the doorbell to be heard in the back yard and the back room and well everywhere else in the small house while also being added value of being able to hook up a phone (Bluetooth or 3.5mm) when they wanted to. I have had knowledge of transducers/exciters for a while, but, mostly as a parlor trick (bone conductors "look ma! no ears!", and those junkers that you just set on a desk and make your desk into the speaker). so, the research path on transducers lead me to PE (clearly the right path)...and a shopping cart waiting to be purchased.

so here's the parts I was considering (well the ones that are reasonably relevant):

Lepai 2020A+
Parts Express BT-1A
Dayton Audio DAEX25FHE-4 Framed High Efficiency 25mm Exciter 24W 4 Ohm
also the 5A PSU for the lepai (as reviews on that amp suggest you can't really get the full juice on the stock 2-3A PSU)

also based on reviews and things I've gleaned from other sources I went with the 24w exciter to give the amp a little room to breath. as a bonus, seems to be an exciter you guys like as well.

so, one of the biggest things about this set up is that it can't look horrible. my original thoughts were to use mirrors or glass as the material for the exciters but, that's clearly been thrown out the window (pun intended) based on everything I've read.

so, what I've gleaned from this thread is that the XPS (either the pink stuff from HD or the green stuff from lowes....the green stuff seems to be stiffer) still seems to be everyone's horse of choice. though ply seems acceptable as well. if I can use plywood for the exciters then it would be a lot easier for me to make it pretty without having to build a crazy enclosure for the panels. I'm not looking for super extreme audiophile performance, but there's no reason to do something wrong just because you're not looking for the absolute best performance.

so, here are the questions after the rambling mess.

the amp: clearly not going to expect earth shattering results here, but....reviews are great (especially with the bigger PSU) and the price is pretty unbeatable as well. given the exciter choice, this amp shouldn't pose any challenges should it?

the exciters: rmeinke and others in the thread seem to have used them, and I've seen some other uses of them "in the wild" as well during my research. they look solid. but, clearly lower output power than the thrusters or the other ones listed, but, it's not like I can go any higher given the amp chosen. I should be able to get reasonable performance out of these given the proper material selection and prep?

the biggie: so, what to stick the exciters to. as previously stated, ply, or solid wood would be a hell of a lot easier for me to make pretty, so, that's where I'd like to start the questions. in either case, I'd be looking at a size closest to the small panels that rmeinke mentions (12 x 14ish ?) or somewhere in that range.

I've seen people suggesting 1/8th birch (as was suggested in here) but, that stuff is pretty flimsy and fairly prone to curl and warping. is it possible to use 1/4? has that been tried? has anyone seen anyone use instrument grade materials? like the stuff you'd use to make a soundboard for a guitar? any other hardwoods seen in your travels? any opinion on solid hardwoods vs ply? I assume the same edge treatments would give similar benefits (round all the corners)?

for the xps, do you think that "Fred's" method (glued edges with the spine) would apply to the smaller panels (I know that one's going to be hard to answer since, on paper, his panels shouldn't work as well as they do)? so far, he reports the fullest range.

i'll try to find the link to the ones I saw while researching, but I saw at least one set of panels built where the guy had a piece of 1/8 ply glued to the exciter (in the center, obviously wrong based on documentation) and then was using the mounting holes in the frame of the exciter (they used the daex25fhe-4) to attach the exciter to the uprights of the mounts. basically just using the exciter's tape pad to hold the panel in free space. has anyone tried that method?

sorry for all the rambling and questions, but, I'm a bit hyped at the idea of building these things (and of course, excited to finally be at the end of the thread...glad I never really started reading the audiocircle one).

[rmeinke]

Re: DIY Flat Panel Speaker Love

Okay crapflinger...

1st - Who is insane here??? You are clearly the insane one given the intended usage - "basically allow me to scream obscenities at him in his house any time someone came to his door and rang his doorbell".

2nd - Can I order a doorbell like this for my brother??? He has a nice second home up in ritzy Door Country and think this will provide a certain nuance that is otherwise missing in his overly proper second home. Well done ma man.

Wow, where to start on this. Congrats for reading the entire thread... your more intelligent than I as I have read the AC thread twice (ok, possibly more but won't admit that under normally scenarios...urrrr) over the years.

Lets GOOOooooo...
Cutting through the crap (flinger), I would personally go 1/8 ply panels with balsa strips to keep the panel relatively straight. Better looking and easy to build but I'm afraid you may still need some type of damping material behind the panel to absorb the mid to higher frequencies from the back of the panel other wise they sound bright when placed near a wall. You may be able to curve the panel and use the space made behind the panel for the damping material.

If making a thin enclosure sounds just as easy, I'd go with 1/2 or 3/4 XPS with grill cloth to make presentable and damping material again at the back of the enclosure. Could be just thick enough for the panel and exciter.

The easiest might be a "Fredclosure" where you simply frame the ply panel with 1x2's with the damping material strategically placed within the "Fredclosure". I may have to trademark this before FShow does.

Risks...
I am not sure, exactly, what to expect out of such a small ply panel. They *should* go lower than my tiny XPS panels and if you read the latest posts over at AC, it might play a bit louder than a normal ply panel of the same size. Still... the sensitivity of a ply panel will not be as good as XPS but the exciter has strong output and seems better suited for ply than XPS... high efficiency is right. It is quite powerful.

Obviously, number 1 above is also meant in a "insane in a good way".... in case there was any doubt. ;)

Surely more questions (and answers) forthcoming...

Welcome to the Techtalk forum and the magic panel thread!!!!

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

[QUOTE=Unbiasedsound;2099360]Well, for me I am searching for the right degree of stiffness that sounds the best to me. Its like Goldie locks and the Three bears where one material is too stiff , while another material is too soft and then there is one material that is JUST RIGHT. lol

Yeah I did that knuckle test with both eps and xps panels being of the same size and the XPS has a more hollow solid hard type of knock due to it being stiffer while the EPS has a softer/duller knock due to it being less stiff.

No not really as I am more of an old school type of person as the only measuring tools I use for sound is my ears lol.

Experimented with something new instead of the glue/water mixture I just used plain old paint on the front side only while the back side where the exciter is uses the glue/water mixture. I also carved out the edges of the panels as you can see in the pic similar to the bertagni speakers....of course this is just a demo panel so the cuts are not even shaped or accurate lol

Thats strange how did my photo get removed when I did not remove it???

[Kornbread]

Re: DIY Flat Panel Speaker Love

... programmable doorbell of sorts that would basically allow me to scream obscenities at him in his house any time someone came to his door and rang his doorbell

... insane ... who ... yeow ... sure ... ok ...

Assuming the speaker will be outside? The different kinds of extruded styroboard are pretty much weatheproof, small sheet of lexan, or just start sticking the thing on different kinds of material and see what works. Walk into Lowes with your phone, small portable amp and stick the exciter on everything you can. WORD of CAUTION: In today's world, walking around in public places with wires and black boxes hanging out of your jacket while doing strange things could get you shot!

Worried about looks, anyone you know an artist? Have them turn the panels into a piece of artwork.

[Crapflinger]

Re: DIY Flat Panel Speaker Love

rmeinke - once I get everything working i'll definitely give a full parts list, but it's pretty simple (the doorbell part). basically uses an Adafruit Audio FX Sound Board which is a little flash chip with "triggers". you can load it up with short sound clips and then use the triggers to do various things (play them randomly, play them in order, play them as long as the trigger is held, whatever). i'll be using a little wireless remote relay I got from china to trigger it. the audio from that will go into the lepai along with the Bluetooth and another 3.5 mm connector (so as to allow for phones to connect) which should allow for the doorbell to ride on the same audio channel if you're listening to music at the same time as someone rings the doorbell (of course, I "think" I might have a way to completely drop the other audio sources when the doorbell rings since the wireless relay has both NO and NC closures but....not sure...would probably require some other circuits since it's a momentary contact....but that's neither here nor there)

Kornbread (hopefully jalapeno cheddar) - not permanently outside. if he wants to use it in the yard he'd have to take it out there. thinking of making it in such a way where it would all be mounted on a stand, so he doesn't have to mount it directly to the wall, so he can get ye olde panel magic by putting it further into a room). also, I've been kicked out of my fair share of lowe's in the past after finding an open outlet in the lighting section.

so, no cringes at the amp (yay!) or other general ideas so, I guess I'm not completely nuts

if I go XPS I can definitely build an enclosure for them, but if these particular exciters are better on ply, well, that just helps me out a lot hehe. if there's no enclosure on the ply, would one still want to knock down the edges and round the corners?

though, the hybrid panel seems reasonable as well. perhaps the 1x2 frame with a 1/4 groove near the front of the frame that the ply would slot into, with some kind of isolating material (thin squish insulation, some kind of rubber gasket, etc..) to center the panel in the groove so that the edges aren't locked then the exciter in the 2/5ths position, possibly a spine, and a back sheet of felt stapled around the edge to dampen the back scatter?

I've got a few things to do at work today that I've been shirking in favor of completely immersing myself in the wonderful quest for panel magic, but if I get time I might fire up sketchup and make a model.

also, if anyone knows (if not i'll ask PE or Lepai)...the RCA inputs on the Lepai amp...are those phono or are they capable of doing line level (from a headphone jack)?

[Crapflinger]

Re: DIY Flat Panel Speaker Love

I did find some time.

https://3dwarehouse.sketchup.com/mod...b-e1140b637957 (best viewed in chrome unless you want to DL the model in Sketchup)

that's with just the 1/8 panels and balsa stiffeners. it's not.......all that accurate...but...whatever. the connection to the panels from the main box would be 1/2" black iron pipe with flanges (or possibly copper). on the exciter side it would be connected to the exciter which would be supporting the 1/8 ply (unless that's completely not suggested, at which point...suggestions welcome. I would also try to magnetically isolate the flange from the exciter but....didn't feel the need to model that).

will likely modify later to make a mock up of the fredclosure hybrid and xps enclosure.


edit: well...had a bit more time apparently https://3dwarehouse.sketchup.com/mod...3-742d360e08a0 XPS version. 1x2 enclosure with 3/4" green stuff and a spine. about 1/16th between the spine and the exciter for some kind of isolation goop though could be 1/4 or more if I moved the xps closer to the front of the enclosure. one side has grill cloth cover as an example. also using the patent pending rmeinke magic eraser isolation material around the edges.

[rmeinke]

Re: DIY Flat Panel Speaker Love

if I go XPS I can definitely build an enclosure for them, but if these particular exciters are better on ply, well, that just helps me out a lot hehe. if there's no enclosure on the ply, would one still want to knock down the edges and round the corners?

I didn't with my ply panels but would at least round the corners and break all the straight edges if I were to listen for long periods.

though, the hybrid panel seems reasonable as well. perhaps the 1x2 frame with a 1/4 groove near the front of the frame that the ply would slot into, with some kind of isolating material (thin squish insulation, some kind of rubber gasket, etc..) to center the panel in the groove so that the edges aren't locked then the exciter in the 2/5ths position, possibly a spine, and a back sheet of felt stapled around the edge to dampen the back scatter?

You have options here on construction... don't think it matters much so long as everything is glued and nothing is rattling. I'd put more damping material on the back if they are going to be within a foot of the wall. They sound harsh when wall mounted due to the high freq. output behind the panel.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hey Unbiasedsound,
How did you prepare your EPS panels? What size are they and did you listen to them on stands or? If not on stands, how did you suspend them for listening?

Bought some cheap EPS and curious what you built specifically.

Later boys!