Homemade Omnidirectional Speakers In A Unique Enclosure

While studying acoustics in college (university for non-Americans), [Nick] had a great idea for an omnidirectional speaker. Some models available for purchase have a single speaker with a channel to route the sound in all directions, but [Nick] decided that a dodecahedron enclosure with 12 speakers would be a much more impressive route.

To accommodate the array of speakers, the enclosure needs twelve pentagons with a 58.3 degree bevel so that they fit together in a ball shape. After thinking about all of the complicated ways he could get this angle cut into the wood pentagons, he ended up using a simple circular saw!

Once the enclosure was painted [Nick] started wiring up the speakers. The equivalent impedance of the array of 8-ohm speakers works out to just around 10 ohms, which is easily driven by most amplifiers. The whole thing was hung from a custom-made galvanized pipe (all the weight adds up to about 15 kilograms, or 33 pounds for Americans, so the rig needed to be sturdy). We’ve featured other unique speaker builds, but this is the first 12-speaker omnidirectional speaker we’ve seen. [Nick] is happy to report that the speakers sound great, too!

36 thoughts on “Homemade Omnidirectional Speakers In A Unique Enclosure

  1. I make dodecs on a compound saw with a little jig to get the side angles right. You can bang them out pretty quickly. It helps to print out a pentagon and use rubber cement to put it on your pieces so you can make sure your cuts are accurate.

  2. I like the build, in the future consider chamfering the inside of the mounting hole.
    Depending on the speaker, enclosure and so forth that might/will greatly improve the frequency response :)

  3. Not a first. I saw one in Pop Sci back decades ago. They went further, it was set in two gimbals and thus would spray sound in all directions. It was part of a live electronic music act. This would be better than a Leslie on chorale speed, it would sound wild at fast spin but not like a Leslie.

        1. Speakers designed to play back recordings are not supposed to sound like anything themselves. In fact any speaker that exhibited any musical properties on its own would be considered terrible sounding, if it altered the material is was trying to reproduce, in any way. I have never actually seen a commercially produced loudspeaker enclosure made out of solid wood. I have seen quite a few speaker boxes by now personally too.

          They are made out of particleboard, of MDF. Which while being wood products, are not exactly natural wood themselves. Those materials are selected for their particular sound deadening properties in fact.

          So I’d imagine a dense enough plastic would make a great, albeit rather expensive speaker enclosure. Or in short, you are absolutely wrong.

          1. You can use natural woods laminates (plywoods)

            Orders of preference would be.
            good quality ply woods
            poor quality ply woods
            Chip board

            It’s not sound deadening that you look for so much as stiffness, (hence good quality enclosures would have as much glue/bracing and screws as possible.)

            Solid woods would make ideal speaker building materials, IF they are well seasoned, hard woods being the best, and then softwoods. the reason these would make ideal speaker building materials is their hard/stiffness, resisting flex. -every bit of “flex” in a speaker enclosure is basically, using the sound energy to flex wood (so wasted), or flexing back and fourth, likely at a resonant frequency, -which may be ideal if you happen to have a specific lul in response at said frequency, but usually is bad…

            But as said they have to be well seasoned, otherwise they are not going to like being inside a house, and will either dry out, or wet up and warp or crack.

            I can’t understand why the array of speakers isn’t designed to give an 8 ohm impedance, (wouldn’t have been difficult to wire them up like that)

  4. Elemental Designs made an omnidirectional subwoofer like this a few years back. You could run it as a dipole if you wanted. Although the actual benefits of this at low frequencies are questionable. But for mid range I can see this being useful. I wonder what the high frequency polar plot looks like. I’d imagine there would be issues with beaming or comb-filtering. Not that it would be easily audible. Either way, neat concept.

  5. Omnidirectional? I can’t remember being at any performance where the audience was located omnidirectionally from the stage. Interesting looking speaker foreclosure though. My guess is, one could as sell as many of these, as one wants to build. No saws that I could see in the photos. Circular saw doesn’t necessarily mean “Skill saw”, a table saw is a circular saw as are many others. By taking the time to do so safely, no doubt these cuts can be done safely using a portable circular. The tower speaker enclosures look nice as well.

        1. In a way, this is incorrect. Everything that makes sound naturally has a tendency to send sound in all directions. Think of a violin. When someone plays a violin, it doesn’t ONLY aim sound right at you. It throws sound everywhere, in front, behind, up, down, all around of the performer. Most instruments are this way in fact. It is therefore rather feasible that in certain applications, having a speaker that throws sound in every direction can have a very life-like effect allowing the source material to interact with your room in a very natural way, a way that directional (read: conventional) speakers cannot. The success of such a technique though is going to rely heavily on your source material and listening environment.

    1. Perhaps to you a table saw is ostensibly a circular saw, because they share the same shape blade. But to the tool using world table saws are far different from your garden variety circular saw. Why even a Skilsaw is a specific type of a tool. It likely isn’t what you think it is either. Skil might even label their sidewinder models Skilsaws, because they’re Skil, but even those are not actually Skilsaws.

      Nope a real Skilsaw is a worm drive circular saw.

    1. Why would that be a fail? Closed cabinet speaker designs do this all the time. Combined with the right speakers this can give excellent, accurate sound reproduction.

      And given its name, I think it might just be that the maker WANTS to push air in omni directions at the same time…

      1. Exactly. In some situations you can want to send the same signal in every direction. For example, there many people who have digital pipe organs in their home. In a real pipe organ, a pipe sends sound in literally every direction. Having speaker arrays like this would make their sound more lifelike at your house.

  6. There are way too many people here who would all do a favor and keep quiet…

    Either read up and learn why you dont have a clue or tell these things to the next tree in your neighbourhood.

  7. I think that if he had incorporated holes though the enclosure, perhaps one at every corner, I imagine that he’d have an efficiency boost. When all the speakers are looking to do the same thing at the same time, it will create internal positive or negative pressure. Thinking about it more, it seems tricky to have the pressure vents planned so that they don’t destructively interfere. I might just make one of these to play around with it.

    1. Reply to self after some research;
      Ported vs non-ported is generally determined by the speakers you’re using. Ported enclosures don’t pressurize internally and speakers made for ported enclosures are usually stiffer to assist the speaker returning to “zero”. Non-ported enclosures create high and low pressures internal to the enclosure and have more flexible membranes.

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