No banana for scale, but let’s say that it’s not too big and not too small. The dimensions are 295mm tall, 270mm wide, and 240mm deep. If I had to do it again, I would be tempted to go a bit wider and touch less deep. It’s probably better to be large in one of these dimensions as opposed to both of them.

Here’s the top. It has a jack for charging, a connector to program the DSP, a switch to turn it on and off, and a battery gauge.

The speaker also has a built in handle that’s way chunkier than it appears, but is still particle.

The big BOM pieces are a Dayton Audio LBB-5Sv2 for the BMS (battery management system), a Dayton Audio KABD-250 2 x 50W for DPS, amplification, and Bluetooth, a Peerless by Tymphany BC25SC08 tweeter, and an Italian-but-made-in-India woofer (a Coral PRF 165).

The print itself is three pieces: the bottom bit (black), the middle bit (white, blue, and white again thanks to not having enough white left to do it all in white), and the black top. Here’s a CAD view that more clearly shows the three pieces:

the three pieces are held together with heat-sets and m3 bolts. There’s also a tong and groove like joint to help the enclosure leak less air. I haven’t noticed any evidence of air leaks while listening.

The amplifier and battery board mount to the bottom like so:

The middle was printed with some supports for the driver overhangs, but the ports and everything else were designed to print in place without supports.

This is certainly not meant to be audiophile build, but it’s surprisingly decent. This isn’t my first blue-tooth speaker, or even my first printed loudspeaker enclosure, but it is the first that was somewhat intentionally designed to have OK bass response while also being reasonably compact.

It measures fairly well. Frequency response, along with harmonic distortion, is pretty good. There’s zero windowing or smoothing on this plot. I suspect the distortion spikes at 1 kHz, 2 kHz, etc are induced by the Bluetooth stack the board is running since they’ve shown up in multiple different enclosures and with multiple different drivers.

There’s no nasty ringing, caused by either the drivers or the enclosure, so life is pretty good:

  • j4k3@lemmy.worldMEnglish
    2·
    6 months ago

    Awesome project. Reminds me of Hexibase YT type stuff. I’ve got a spares shelf of drivers but would need to build an Arduino project to characterize them and the output empirically, and still haven’t gotten motivated for that level of math project.

    I assume PLA? If that is ABS I’ll lose my mind.

    • IMALlama@lemmy.worldOPEnglish
      2·
      5 months ago

      Thanks! Hexibase’s builds are super cool.

      If by characterize them you mean measure the driver’s t/s parameters you can do it with a multimeter, a resistor, and basically any amplifier using a computer to generate the frequency. Elliot can be a bit verbose, which makes his instructions somewhat hard to follow at times, but here’s a guide: https://sound-au.com/tsp.htm

      The top and bottom are PETG. The middle section is ASA. 0.6mm nozzle, 0.3mm layer height, 150% extrusion width, two perimeters and 30% infill. I was cruising, but did limit my max flow rate to 25 mm^3. I could have gone even faster, but I was in the rate of diminishing returns for print time. I printed it in my Voron, but it did need some extra insulation to get the chamber temp high enough to avoid warping. The print completing completely successfully told me it’s possible to do big ASA prints with a 60 degree chamber temp, so I’ll be spending the time to make some nice insulated ACM panels.

      • j4k3@lemmy.worldMEnglish
        2·
        5 months ago

        That is freaking awesome! I tried both ABS and ASA with the MK3 and a sealed enclosure, I can do some fairly large prints up to something like large grapefruit scale, but anything like your enclosure will separate on the corners. I think it is simply a bed slinger issue that is unsolvable. Awesome to see the tangible results and justification for building a 2.4.

        • IMALlama@lemmy.worldOPEnglish
          2·
          5 months ago

          I had prints doing exactly what you described on my CoreXY because ABS and ASA are very warp prone. For me it all came down to chamber temperature and a solid first layer. I think you should be good to go on the latter thanks to your MK3.

          You’ll need active chamber heating at a minimum to pull off larger prints. This doesn’t necessarily mean an aux heater, but it does mean bedfans. I’m not sure how easy those are to implement on a MK3, but I would be amazed if no one hasn’t figured out something, especially given the size of the community. In my case, I’m using 4x bed fans with two doing double duty in a filter.

          My printer is a 350mm^3 Voron, which means its acrylic panels are fairly large. More surface area means more heat loss, so I need panels that do a better job of retaining heat than simple acrylic. This might also be the case for you thanks to having to move your bed back and forth. I’m hoping that ACM+radiant insulation will get me there. This print happened in a 60 °C chamber.