Hi welcome to the Eev blog an Electronics engineering video blog of interest to anyone involved in electronics design. I'm your host Dave Jones hi not in the lab today I'm in the study or the Amp Hour recording studio as you know, I've got the Ow.com it's a radio show with Chris gaml. Check it out if you haven't and this is where I record it from I've got my studio mic and because I'm in a tiny study here office study it echoes a lot. had nothing on the walls.

So I thought I'd build these excellent acoustic panels because before if you've seen the photos, I had to have pillows up here I had to go get the cushions from the lounge in there and pack them all around here so it would sound good. So I don't get Reflections off the wall. they bounce off the back wall and it just Echoes all over the place. So I decided I'm going to build These acoustic panels actually I thought that I would buy some first of all, but they're quite expensive if you go to the uh, some of the Commercial Supplies they could be hundreds of dollars each to buy basic panels that you just hang on the wall and I thought well jeez, I can make my own.

There's not much in them. there's a bit of pinewood, a bit of fabric on the front, some acoustic material in the middle of backing board. That's about it. How hard could it be? So decided to build these.

So here's a video showing how I built them and hopefully the results. Okay, I'm going to start out with some 42 mm x 19 mm X 2.4 M long length of uh Pine that I could get from the hardware store. it was just a a standard length. so there it is and I'm going to use this to construct my frame.

so I'm going to Mark along here at 600 mm intervals and then that will be used for my angle cuts and I'll be able to get four top and bottom pieces out of this 2.4 M length. And because we aren't that fuss with the exact 600 mm, Dimensions I'm just going to cut smack in the middle of the line with the dropa cuz it's easier. even though the Uh blade itself is several millim thick, eh, doesn't matter, it's all going to even out in the end. Let's go now.

I'm not too fussed about the height actually I was going to do a meter or round about that, but I thought why not do the Golden Ratio which is a classic Uh ratio of one length to another length which is supposed to have you know pleas in qualities to the eye aesthetic qualities. So 600 by uh, the golden ratio which is 1.618 roughly it's an irrational number gives about 971 mm so that's near enough to the meter I wanted. So I do these Uh panels 600 by 971 mm And well, for all the audio fools out there, the golden ratio could sound better. Beauty So there, you have it, we have our golden ratio frame.

Let's stick it together and the next step is to use our Corner clamps here. So I've got I'm going to have four corner clamps on the entire frame and we need some uh, woodworking glue and we're going to stick them together and then we're going to staple them as well for some extra strength. Okay, what I'm going to do now is apply some uh woodworking glue to both surfaces, join them together until we got a nice join and normally I would corner clamp that, but what I'm going to do is I'm actually going to uh, get my staple going and I'm just going to put a staple in there to hold it together. so let's give that a go bit of strength there.

There we go that should hold that together nicely And there you go. That is now a reasonably solid frame. It hasn't finished gluing yet, but with staples both sides, it holds together very nicely. and just to make sure the frame is a bit, Square I'll put the Uh four corner clamps on it and let it dry I know I'll probably have a bunch of woodworking experts tell me that's the wrong way to do it, but I don't care.

that's how I did it. And of course, for a normal picture frame, you would use what are called V Nails uh to do the uh stapling of the corners. but I just don't have any of those. Couldn't get any at the hardware store.

so good. Old fashioned staple gun does the trick. And there's our completed golden ratio frame. It turned out quite nice.

It's uh, seems to be nice and square. It's uh, nice and solid. I've left it overnight. It's all glued, it's stapled together.

Not a problem. time to put the fabric on it. And for the fabric I Got two types. yes, naturally wife approved uh, she color matched them.

For the studio room this is a native Australian Native indigenous Australian Aboriginal Pattern I Love it. It's really nice and we got that and we're going to mix it up with another couple of panels which are just plain black because, well, there's black inside. You know there's a bit of black in this pattern and apparently it matches. Let's give it a go.

now. we just need to staple that in place. You start in the center of one end like that and let's do it. and next up, we just want to do the other end in the center as well.

So weetch, stretch it a little bit like that and we bring it over and we just staple that in place once again in the center. and third, we do the center of the other side. So let's pull that over reasonably tight and give it a go. Okay, and once we've done that, we want to, uh, take one side here and do halfway along here and then you want to go into the opposite Corner over here like this and pull that a bit tight and once again, halfway along should be just fine.

And these ones here, we don't go halfway. We'll actually do it a bit closer like that and we work our way around like this. Just have to make sure there's no creases there and it's all neat and tidy. It's not easy, you've got to do some multiple folds there, but just get it.

so it's neat like that. There we go. that looks pretty neat and we'll just staple that in place. Excellent, And there it is.

our completed frame. It looks really, quite nice. I Like it turned out really well, this is the black One time to do uh, time to make some more frames. This was just a trial so we'll make some more frames and we'll do them with the other Fa Fabrics as well.

I'm going to have six or seven frames in total. Next up, we got acoustic insulation material now. I've got this Australian-made uh, Tontine Acoua Zorb 3 material specific specifically designed for sound absorption now I got the huge roll Big 10 m Roll by 1.2 M wide. so it should do my panels just fine.

In fact, I could probably get uh, you know, more than a dozen uh panels in this so I'm going to have some left over, but it's pretty cheap stuff. uh, not expensive at all. and um, it comes in different thicknesses. this is a 25 mm thick one.

It comes in everything up to 100 millim thick. Now the thicker the insulation uh material the greater the um sound absorption at the lower frequencies your base frequencies. but um, even this 25mm one. uh, you know I couldn't really have a thick panel it look silly on the wall.

The wife didn't approve. so I'm stuck with the 25mm one but even this will have a near perfect um, sound absorption. uh figure at 2 khz and it start it drops down to about3 or something like that, down at a couple hundred Hertz But that's going to be more than good enough for my purposes. And the great thing about this material is that it's a polyester.

It's a thermally bonded polyester M material and it's really, uh, easy to work with and most importantly, completely safe. There is, uh, you know there the MSDS the material safety data sheet for this thing basically says you can. You can almost eat the stuff right. It's unlike the fiberglass insulation you typically get in houses and not only for thermal, but for acoustic absorption as well.

So this stuff I'd highly recommend getting the polyester stuff and I believe it's fire. uh rated as well I don't have to wear gloves, mask anything I can do whatever I want and it's uh, completely safe and it won't emit any volatile chemicals or anything else. Good stuff. Get polyester and we have our first piece.

It cuts really easy with a pair of dress making scissors. No problems at all. We got our first frame. Let's hope it's uh, reasonably accurate.

and because our wood is 19 mm uh, thick and this stuff is 25 mm? uh thick. I haven't really thought about how to stand it off. Maybe it will actually compress down adequately, but I don't think so. It may actually, uh, push.

It may actually push the material out at the front, but I don't think that's a big deal. Maybe I can just put a backing board straight on that now. I've got the frame flat on the floor like this and well, you can see a bit of a there's a little bit of a bulge here like this, so if I put a backin frame directly on the back, um, it doesn't compress enough, there's not enough, uh, tension in that material to actually compress it. so there's a bit of a bulge.

but really, you can't see it. It's next to impossible to see that. So I don't think that's a big deal. I might just, uh, screw a backing board directly onto that I Think Well, there you go.

I Finally finished. Eight panels complete. This is the lovely Aboriginal artwork one. Check it out! I've got four of these, plus, uh, four of the black ones as well.

So time to hang them and you can see how they're a bit and you can actually see how they bulge a bit in the middle there if I try and hold them together like that. As you can see, there's a there's a bit of a bulge from the filler material inside, but I reckon that adds nicely to the effect of them. And here are the final panels in my recording studio: SL Study: There's got I've got four panels up there and I've got three panels on the rear wall here and that's it. and it's made a hell of a difference.

Let me tell you, let's uh, see if we can do some audio tests and hear the difference. And here's the exact same room again, same camera angle hopefully. but I've taken the panels down and you can really hear the echo? I hope you can hear it on the mic. Um, and the panels on the uh, rear wall are gone as well.

So uh, really, there's a massive, massive difference? Check. Check. Check One two Check. This is a test with the acoustic panels installed, seven panels facing the computer.

Check. Check Check One two. This is a test without the acoustic panels and there is a hell of an echo in here. Hopefully you can hear it.

It's terrible I Know they're all thinking I'm so white and nerdy Just too white and nerdy just too white and nerdy can't see I'm white and nerdy look at me white. I r the gangers. they see me mowing my front long I know they're all thinking and I'm so wide and nerdy think I'm just too white and nerdy think I'm just too white and nerdy see I'm white and nerdy Me: I'm white and nerdy nothing on the walls and we got the echo. You can really hear it on speech.

It's a bit difficult to hear it on music, and just the act of putting three panels on the wall like that makes a fair amount of difference, but not nearly as much as if you um, as if have the whole seven panels in. Stall especially when I'm using my USB uh, Studio M mic like this because it's very directional. It really only uh, takes audio from the front face here. so it's um, it really.

you can't that takes out a lot of echo just having a good Studio mic like that. But these panels are great I Love it. So there you have it. There's my do-it-yourself acoustic panels.

massively happy with the result. Even with the 20 5 mm thick acous Abol material, you can get it up to 75 or 100 mm thick if you really want to get that base right down. But this works. just a treat for my simple recording studio like this.

And really, they were dirt cheap. They cost about 25. Oh, I think less than $25 a panel. fully constructed I think the material was actually the most expensive part of the whole thing.

So what an absolute bargain! And they look fantastic! And best of all, their wife approved. See you.