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Tectonic TEBM46C20N-4B BMR

Built a tiny sealed box for the BMR 3inch. Here is what I got with a simple notch:

15* left and right and30* left and right:

Then I added a tiny cap and tiny inductor to take care of the top end:

Dats as a reality check:

So how did I do for something the size of a Bose cube?

jhollander
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Comments

  • If it sounds good, then it is good...Do you find it sounds better with the top octave brought down?

    I am confused though on how you managed to have gating set to 5.0ms, yet on the impulse response it looks like gating is set more like 2.2ms. Anyway, set gating to 4.5ms to get behind the reflection.

    I'm not deaf, I'm just not listening.
  • I wasn't too worried about the gating and left it at the default setting.
    I have only listened to a few songs on them in stereo. I think for their low cost and small size they will be fine for desktop use or for a small tv setup. I hope to pair them with a woofer and give them a good listen soon.

  • Hey Ken, since you have it in a box, can you run distortion on the BMR?

  • Ani - erin did measurements and a review of the 2 inch BMR. I'd imagine the larger ones have better HD numbers.

    https://www.erinsaudiocorner.com/driveunits/tectonic-elements-tebm35c10-4-miniature-bmr-driver/

    ani_101
    Don, Donno, or "Hey you" all work for me, But never "Mr Johnson"
  • Ani, I took the HD measurements and forgot to save them :angry: I will remeasure Thursday. I also hope to get to Meniscus and pick up the correct cap and coil to take care of the top end and leave a little sparkle.

    ani_101
  • @ani_101 said:
    Hey Ken, since you have it in a box, can you run distortion on the BMR?

    measurement was taken at 3ft on axis. Not too bad.

  • well it's -50db till 700 and -40 till about 300, would be a good mid range and should be easily able to hand off to a small inexpensive tweeter dome/ amt / ribbon. Given the FR plot, should be able to XO above 5k

  • With what I'm hearing these dont need a tweeter. I'm thinking these need paired with an 8inch woofer. I might pick up a pair of the sb acousics pfc woofers. They seem to get good reviews and the cost is right.

  • That is a nice clean looking distortion graph, most impressive!

  • Can you post your notch filter specifics?

  • 5.1uf, 8.2ohm, .27mh notch with a .1mh to tame the top end.

    JasonPjhollander
  • FRD and ZMA attached this is all held together with just the 4 bolts that hold the speaker in. The 5-way binding post works great in this design. The walls are very thick and the speaker is very solid for being 3d printed. Stuff to taste with your favorite fill.
    The "baffle" is also an adapter ring that makes inlaying the BMR very easy. I can also make it round if someone would like the BMR to mount like a standard speaker. The adapters will be available through Meniscus with the purchase of the Philharmonitor kit. I'm sure they will be available ala-kart as well.
    I hope to refine this 3d printed speaker as a "kit" as well. Currently working on the .1 of a 2.1 system. When being used as a 2.1 system they measure quite well sitting on a desktop and even better flush with a monitor or TV. For those that need a SMALL system, I think this is a winner.
    If anyone here needs any of the files or would like a set printed let me know. I only ask that you do not redistribute without my approval.

  • Just thinking out loud. To make things interesting, using this as a stand-alone for something like computer speakers, you could print almost any shape/+stands/+whatever that appeals to the customer.

  • very cool design -- so dang compact. I'm in for a printed set (email sent).
    Which sub driver will you use for the .1 channel? TB W5-1138? or something smaller like 4"?

  • I have a box modeled with the M5N but don't have a cad file just yet. That should be about 8.25 inches cubed to get down to 55-hz
    I have an idea in my head that will add an integrated port/base to the box. I have not modeled the BMR ported yet, the only reason to add a port would be to help it reach low enough to cross to the M5N I don't think the port will be necessary.
    I am open to other driver recommendations. The M5N is pretty cheap sounds good, looks good, I think it would be hard to beat in a box that small without spending a lot more.

  • TB 5" sub....

  • Do you have the CAD for the driver cutout? That seems to sit pretty well. What printer?

  • Inexpensive option
    TCP115-4
    In 0.15 cubic feet
    Tuned to 50 Hz

  • I have some of the TCP115 drivers in the 4 and 8 ohm version.
    The tang band is amazing and can sound great even sealed in a small box, like DanP's NRNP sub.
    Looks like the printer is going to be busy this week =)

  • Wolf design triumph with two peerless PRs is an option too

  • I love my little Triumph design! Still have one of the two I built.

  • @Wolf said:
    I love my little Triumph design! Still have one of the two I built.

    indeed, i'm a fan too -- not too many subwoofers can be held with one hand! Plus the 25W plate amp is a perfect fit.

    I also built a small TB-W5 subwoofer with a single 7" wavecor PR in about 1/4 cubic foot, but that PR costs a pretty penny. Your biumph design would be more economical with the 8" PR.

  • I wanted to show the "inside" of a print. Almost all 3d printed parts have voids between the walls. This helps save cost and speed up the print process. This is a very simple box with 1/4 thick walls 20% infill and 2 solid layers for the exterior of the walls. If you look closly you will see the triangles are actually forming diamond shapes. This works like a hybrid corigated cardboard. This box does flex a little as almost all do, for its weight and volume it is pretty impressive.

    Turn2JasonP
  • that's awesome -- and these things are truly tiny. looking forward to getting a set!

  • Wonder if you could fill the void in the wall with some kind of epoxy or silicone?

  • Yes, it could be done. I have been thinking about leaving holes in the walls that would fit a carbon arrow. That would stiffen the walls and wouldnt cost too much. I have also thought about crushed kitty litter. Either way drawing the cavities in the box would be alot easier than trying to fill the infill.

  • carbon arrow?

  • @kenrhodes said:
    Yes, it could be done. I have been thinking about leaving holes in the walls that would fit a carbon arrow. That would stiffen the walls and wouldnt cost too much. I have also thought about crushed kitty litter. Either way drawing the cavities in the box would be alot easier than trying to fill the infill.

    I've been messing around and printed a baffle piece like so: 20% infill, straight pattern like triangles in Cura, and then I tell the slicer: no bottom layers. Leaves an open shell I can fill with whatever, and print a solid this piece to glue into the back. So its possible for sure.

    kenrhodes
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
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