Building Distributed Mode Loudspeakers

I enjoy tinkering with HiFi equipment and have often considered building my own speakers from scratch. While I’d eventually like to make my own high-quality wooden speakers, such a project costs more than I’d like to spend at the moment. When I learned about distributed mode loudspeakers, which many websites claim sound great without costing very much to build, I decided to give this project a try.

What makes distributed mode loudspeakers different from ordinary speakers is that rather than using a thin paper cone to vibrate and make sound, this design vibrates any object and turns it into a speaker. I read that some of the best-sounding results came from household insulation material, so that’s what I used.

My speakers use an inexpensive sound-producing component called a tactile transducer glued to a piece of foam. The tactile transducer is like an ordinary speaker without the paper cone, which allows it to vibrate whatever object it is glued to.

Here’s the Dayton DAEX25FHE tactile transducer glued to a piece of foam board, which vibrates and produces sound.

I used crimp-on connectors from the hardware store to attach speaker wires without soldering.

The insulation foam boards I used cost $5 each and came in two-foot by two-foot boards at the home improvement store. As insulation foam is not well known for its exceptionally good looks, I carefully cut, sanded, and painted the foam to match better the room the speakers are in. As you can see in the image below, I should have used a much finer grit sandpaper to achieve better results. This step was exceptionally messy and left crumbs of pink foam dust everywhere, so it is best done outside (with a vacuum cleaner nearby).

The finished speakers match the color of the wall behind them. I intend to redo the foam section and take significantly more care during the sanding stage. I believe it should be possible to achieve a much higher quality finish if I sand more carefully.

I suspended my speakers from lengths of fishing line to allow them to vibrate freely, and I used a few pieces of scrap wood to float them a few inches away from the wall. I also epoxied some metal pins to the foam which act as anchors for the fishing line to be tied to.

Once I mounted the speakers to my wall, I ran speaker wire to my stereo amplifier and I configured it to send more bass frequencies to the subwoofer channel than normal. From my testing, I found that this style of speaker is lacking in bass, so setting them up in tandem with a powered subwoofer was a must. I also had to tweak the treble settings on my amplifier to get them to sound right, as otherwise, they produce a painfully shrill noise at certain frequencies.

Once they were all wired up, I gave the speakers a test. For the low cost, (about $24 for the tactile transducers and $10 for the foam) I think that they sound great. Are they the best speakers in the world? No. Do these speakers blow away their sub-$40 competition? Absolutely! Despite not being audiophile-grade, I think my distributed mode speakers sound miles ahead of the TV’s built-in speakers, as well as the Sonos Beam soundbar. They certainly do a great job filling a large room with lots of sound for very little money.

If you are interested in building your own similar speakers, I recommend searching on YouTube. There are several great guides that go into more instructional detail than I do here.

The completed speakers. Please forgive the messy wiring —this photo was taken during the testing stage.