SHOULD SPEAKERS THIS GOOD BE LEGAL?

[Music] hi we've done a large number of videos on sound [Music] [Music] [Music] [Music] [Music] [Music] a couple of years ago we built an lrad system we took it out into the field tested it and then we demonstrated several methods you can use to protect yourself from an lrad we built an electronically driven active noise cancellation system as well as studying the properties of different types of materials that can be used to block or absorb sound including helium what we discovered is that when you compare all of the properties including cost availability and performance one of the very best materials that you can use for that purpose turns out to be good old acoustic ceiling tiles hold that thought we've also done a number of videos on speakers and a few years ago we did a video on dmls distributed mode loudspeakers unlike a typical commercial speaker which uses a voice coil to drive a thin membrane or diaphragm in a piston-like fashion that produces pressure waves which you hear as sound in a dml that same voice coil drives an entire panel of material causing it to bend and to flex and to twist generating sound from its entire surface area just like a musical instrument like the sound board in a piano like the body in a guitar it produces very realistic sound and has the added advantage of being very inexpensive it has a flat form factor and you can construct the entire thing in a couple of minutes to do this we studied dozens of different types of materials that can operate as the panel they have to have certain properties they need to be relatively flexible they have to be lightweight so that the drivers can accelerate the surfaces and they have to have a high damping coefficient so they don't resonate and when you look at that and combine that with cost and availability concerns one of the very best materials out there is good old acoustic ceiling tiles so we decided to combine both of those systems together and build this what we have is 10 dml speakers located entirely around a small enclosure that contains a computer workstation where someone can sit they can play games they can use this as an audio editing booth and it produces very good sound then we located this entire setup in the worst acoustic environment we could find which is the large room in our warehouse concrete floors steel beams hard surfaces yuck acoustically this is awful and the only nod we gave to modifying the environment a little bit is we placed a small piece of carpet on the floor right below where the user sits to decrease reflections of sound from the floor right below their feet and this system really does work because of the absorption of the material in the speakers the sound produced by one set of speakers is absorbed by its compatriots on the other side of the booth so you don't get any kind of resonance and when you walk into the enclosure and leave the resonant loud noisy environment of the warehouse sounds become quite muffled now as we proceed through the video i'll show you exactly what you need to do if you want to reconstruct something like this in your home or in your apartment but i want to get to the testing and one of the if issues you've got whenever you're doing an audio based video is that whatever we hear here has to be recorded on microphones uploaded to youtube compressed and then downloaded to whatever kind of audio equipment you're listening on something can get lost in the translation so what we've done is we've invited over a bunch of test subjects some of our friends and we've asked them to be honest and give their opinion when they go into the booth and they listen to various music tracks and then we'll do sort of an exit poll and get their opinion about what it sounds like and then finally remember i said that these panels produce sound from all of their surfaces inside as well as out so at the end of the video we're going to crank this up a couple of notches and we're going to have some fun let's get started okay so this booth here that we have you can sit down in the chair there we have the cameras going um and just so you know these two little things hanging here are mics just so we can measure like sort of how these speakers are sounding and how you sound and everything all right but what we have here are a bunch of songs that are all copyright free you can use the mouse and keyboard and everything when you play it um in the lower right hand corner where it says activate windows it'll have a volume scroll thing there so if you want to make it louder or quieter you can do that all right how do i play it just double click any of them [Music] and you can skip through them you can skip through them there uh just audio there when you don't want to keep listening to this song you can x and you can go to a different one so you can choose whatever you want awesome and and just go through what do whatever you want it's really up to you that's that's the whole point of this thing okay okay go for it and make it as loud as you want all right [Music] [Music] what's the last one [Music] so what'd you think there were like actual speakers around like surround sound was it as good would you just say it's better than like a typical computer workstation where you got a couple speakers and a sub or something like that oh hell yeah it was like crazy like this bass and everything was it as good you'd say as headphones oh better than headphones really yes super super let's give somebody else a chance you get something to eat all right i'm going to [Music] what are you [Music] so what did you think sounded really good pretty good yeah yeah would you say that like it was crisp and clear like you could hear well you could make out the the details in the music and everything like that i could make out each instrument where it was supposed to be yeah yeah and uh would it be as good as a pair of headphones which is sort of the standard of like ultimate i have a pair of headphones that i like better but that's a matter of preference and they were very expensive yeah but this sounds really really good okay that's that's that's what we're looking genuine and honest okay great no that's perfect so you want to get some pizza so the way the booth is set up is as a 5.1 system so it's got a left front left rear right front right rear and center speaker the point one represents the sub one of the issues with these panels is that the lower frequency performance improves as you increase the size of the panels but to get to really low frequencies you need enormously large panels and that gets kind of impractical because the effective drop off is around 120 hertz what we do is we set up a sub that's the point one and put its crossover at about 150 hertz to broaden and flatten out the response to the lowest frequencies the other thing you'll notice is the different colors of panels despite the fact that the acoustic seating panels are best overall to get the very highest frequencies the best performance you want something even lighter and stiffer and extruded polystyrene is an excellent material for doing that so after testing we decided to replace four of the 10 speakers with these polystyrene panels and now we get a great response from 20 to 20 kilohertz it sounds a lot better the other thing is that because we have 10 speakers we obviously are running five channels so the speakers are working as pairs so these two speakers represent the left front and they're operating in series we send the power into one side of the actuator we bridge it over to the other actuator and then send it back to the amplifier because each of these drivers that we get from parts express are rated at a 4 ohm impedance by running them in series they're seen by the amplifier as an 8 ohm impedance which is ideal for how the amplifier operates and that's kind of an interesting thing to keep in mind whenever you're using speakers and amplifiers you can adjust the impedance by either running speakers in series or in parallel in series we double the impedance if we ran them in parallel instead of four and four we would have a two ohm overall resistance so it's a useful piece of information okay so what we're doing here is we have this little booth thing and it'll be way more extreme later so the booth if you want to take something yeah fun right somewhat [Music] and you can place [Applause] [Music] [Applause] [Music] [Music] [Applause] is [Music] well so what do you think that's pretty good it's pretty good literally like movie theater like yeah wow yeah and it's amazing like this whole thing probably cost about 200 bucks really yeah and you can build it in a weekend i mean it's really it's really not difficult would you compare this like say to any kind of like regular speaker system like in a house or something like that would you say it's at least as good as that i mean i think it sounds more like a like a sound system like a stage kind of thing like it sounds more like like you know like the big black speakers i have yeah it sounds more like that would you say it's as good as a headphone set which is like the ultimate standard it's definitely close i think okay so yeah it's definitely close okay i might not win well i'm saying it depends on how much the headset is right if it's a walmart pair maybe not it's better than some headphones i've had yeah yeah it's cool no definitely good come on let's get something it's right here okay yeah you can sit down you figured out that quickest out of uh all of them [Music] awesome thank you [Music] so [Music] today [Music] [Applause] [Music] hey so john what do you think it sounds amazing oh sure how do i do that oh just you can just click off just click on the screen oops oh okay um so what do you think about just the quality the quality sounds really good yeah i mean it sounds a lot better than some of the headphones i use for gaming really it really sounds amazing and there's not really any any spots in here where the sound would be lower or higher it just sounds like you're surrounded and if you were gaming you could definitely game in something like this oh yeah and you would hear very well yeah and you'd have to justify to everybody else in the house while you were doing this oh exactly yes the setup is a little interesting yeah yeah but it's a really it sounds incredible yeah and what's nice is they're dull you know so you don't get that kind of resonance and do you have is there a difference between why you have alternating panels or yeah these uh styrofoam panels work better at high frequencies gotcha the acoustic sealing panels will work better at lower frequencies and because it's a five point one system this is one speaker this is the second one oh gotcha that's another one so they work in pairs yes yeah awesome yeah so it sounds great yeah okay so this is how the panels are constructed one major concern is you need to isolate them as much as possible from the environment even if you take one of these panels set it up on a table and lean it against a wall you will seriously deteriorate the performance what we discovered is the best way to isolate them is to hang them vertically from some very thin kevlar fishing line from some hooks and because of the load we don't want this line to eventually saw its way through the surface and so by drilling some oversized holes and inserting short segments of plastic pipe potted in some epoxy we distribute the load and we protect the panel there's another method that you can use in these thicker polystyrene panels we just drilled some oversized holes and put some long stemmed eye bolts down in a little bit of epoxy and that also helps to distribute the load just two choices in how you might want to hang these now the driver has to be mounted on the back surface and because these materials are soft in the case of these panels fryable to get some just load distribution and provide a better surface once we locate where we want to put the driver what we do is we pour about 50 or 60 milliliters of a thin epoxy solution and let the material just flow out as the panel is sitting horizontally the end result is that the epoxy gets into the fibers produces a much stronger surface and the top surface becomes glassy smooth when you get these drivers from the manufacturer they come with an extremely strong double sticky tape when you peel off the protective layer and you insert it onto the top of the epoxy it really grabs we've had these in our home for over four years we've never had a failure the other thing that you'll notice is that the actuator is not located exactly in the center of the panel the reason for that is we want as little redundancy as possible in the distance from the driver to the edge of the surface to reduce resonance peaks so this is mounted at forty percent sixty percent forty percent sixty percent of a panel that's not exactly a two to one ratio and that really does improve its performance yeah you should okay so he closed it off so i have to get in here for a sec sorry yeah perfect you can make it loud quiet and you can skip through it or you can close and go to the next one whatever you want yeah perfect good luck thank you that's awesome it's a good one that's pretty cool [Music] i like this [Music] i'm good [Music] this sounds really good you like it yeah [Music] sure [Music] and you can turn it up [Music] [Music] so what'd you think cool i think it sounds really good don't you you want one of these at home well when we're done we'll just pack them up yeah great idea yeah sure we've got it loud enough yeah right exactly well cool really nice yes that's so neat how clear it sounds yeah i was surprised too the first time i heard it i thought it was okay so little booth here yep so if you want to enter and sit down i'm going to close this panel behind me yep my dad will then come out and ask you what you thought of it cool all right [Music] so [Music] [Applause] [Music] [Applause] [Music] [Applause] [Music] yeah i mean just how uh the clarity of it all even with the hearing aids there's no no backing yeah i don't get any back noise from it so you could listen to this comfortably like if he had the right volume and everything yeah well that's what that's that's i guess what i guess what i mean is this it's the clarity and the com being able to hear it there's no like distortion despite the fact that you got the hearing aids yeah wow which is pretty neat yeah it's really neat i told your wife i was like i was thinking i'm like we could just gonna get out of here i'm gonna hit alex up for the playlist okay pretty good playlist yeah no problem that's pretty cool you guys build those speakers yeah it was just it was an experiment several years ago just playing around [Music] i'm [Music] crazy [Music] oh [Music] so [Music] i'm gonna hit alex up for the playlist [Music] i'm [Music] crazy [Music] oh [Music] you

Channel: Tech Ingredients

Views: 513,395

Keywords:

Id: GslJ8Hf4WwE

Length: 28min 25sec (1705 seconds)

Published: Wed Jun 15 2022

Reddit Comments

[u/MrNomad101]

They’re better installed in walls. Allows for more sound and wave transfer , long wave lengths , etc . I designed my own to use in galleries and museums. They sound great.

Super easy to do

[u/CynosureAK]

These are DML speakers. There is a whole sub dedicated to them. With proper materials and crossovers they can be amazing speakers though they do offer a different kind of sound and it also depends on the genre.

[u/Another_Toss_Away]

Anyone can make speakers...

Unfortunately many do~!

:(

[u/joshmelomix]

I think dml's sound like shit and kind of bored of seeing them get any traction.