Project Rectonics aka Kamu M1: Powered streaming speaker

[kemmler3D]

Very cool so far. Did you create the frame for the grille and 3D print it?

 

[KamuDesigns]

It sure is tight in there!

Fortunately the fully 3d printed version of the enclosure will have 4 more liters to work with

 

[KamuDesigns]

Very cool so far. Did you create the frame for the grille and 3D print it?

Yes! Everything but the sidepanels and electric parts are 3d printed.

 

[KamuDesigns]

Tested the tuning today. It was a bit lower than expected. I was aiming for 47hz and end result was 40hz. Surely I can raise it a bit since the last portion of the resonator is separate, but I've could have gone with a bigger port if I knew that tuning is going to lower. Apparrently measuring port lenght at absolute centerline produces lower tuning than intended. Go figure
View attachment 1169524

 

[KamuDesigns]

I took 2 bmr drivers and measured them in a wg close range so don't pay much attention of the shape of the fr. The whole idea is to compare drivers.

Apparrently they are of a constant quality. Another one is broken in and another isn't. They still do measure inside 1db so I'm not going to go through the rest of the drivers.

 

[KamuDesigns]

I assembled the speakers today and attached the logos. Still working on the grilles, but I can dive into the amps dsp tomorrow and take some measurements.

 

[badspeakerdesigner]

Looking very spiffy there. So close. Thing is like 99% there in terms of looking like a commercial product and that's impressive.

 

[KamuDesigns]

Looking very spiffy there. So close. Thing is like 99% there in terms of looking like a commercial product and that's impressive.

That 1%? Woofer screws?

 

[badspeakerdesigner]

That 1%? Woofer screws?

Well for me it's the very slight burrs (idk what to call them) where the wood joins the printed enclosure. I don't think the bolts are really a problem, but the woofers basket isn't the most aesthetically pleasing by itself. With a grill it won't matter and your grills looked really cool.

 

[KamuDesigns]

Round or chiseled? For the life of me I can not make up my mind...

 

[badspeakerdesigner]

Round

 

[jmf11]

Hello,

This is an brilliant result and innovative way to proceed. For the 3D printed part, which level of infill did you used? Do you consider that it is the right one, or would increase/lower it ?

Does it "rings" different from wood?

JMF

 

[KamuDesigns]

Hello,

This is an brilliant result and innovative way to proceed. For the 3D printed part, which level of infill did you used? Do you consider that it is the right one, or would increase/lower it ?

Does it "rings" different from wood?

JMF

As far as stiffness goes it's quite the same as birch ply. I used 3 0.6mm walls and 35% grid infill. I could have gone a bit higher, but I absolutely wanted to keep the halves under 1kg. Cabinet structural resonances were still above woofers band @600-700hz so I'd call this a success.

 

[jmf11]

Thanks a lot for this feedback. Your project demonstrates that 3D printing makes sense for speakers, with reasonnable infill. Working with halves solves prart of the issue related to the bed size. And printing on the side offers new possibilities.

Well done !

I imagine that it still represents very long prints...

JMF

 

[KamuDesigns]

Thanks a lot for this feedback. Your project demonstrates that 3D printing makes sense for speakers, with reasonnable infill. Working with halves solves prart of the issue related to the bed size. And printing on the side offers new possibilities.

Well done !

I imagine that it still represents very long prints...

JMF

You just need to upgrade your machine's flow and cooling capability so you can print with larger nozzles. These averaged around 27 hours per half so it's not too bad.

 

[KamuDesigns]

Final design iteration of the grille, but I need better glue. I used spray contact cement, but that seems to have tendency to loosen up when heat is applied. I tried with a hairdryer and sure enough the glue gave out.

Since I absolutely need a glue that actually hardens, I'm going try to get my hands on some spray ca and spray accelerator.

Maybe with that I dare to try with the brown fabric.

 

[BDE]

Nice looking speaker!
Did I miss how you made those grills? Or just purchased (source)?

 

[KamuDesigns]

Nice looking speaker!
Did I miss how you made those grills? Or just purchased (source)?

They are also printed. The fabric is glued from the front side just from the lowest point around the 'dustcap' and from the backside.

Front side is glued with spray adhesive and ca in the back.

It stays in place with the aid of neodiym magnets.

 

[MCH]

Hi @KamuDesigns , amazing project! I got my first 3D prints done a couple of weeks ago and learning on the go.
For electronics enclosures i am using PETG because I am afraid that PLA starts to soft if electronics get a bit hot and don't have a dedicated area to print ABS. But I am not finding PETG so easy to print, and worse than that, i am seeing that the dimensional stability is not great. Well, they are thermoplastic s after all. I wonder if it is worth the risk of sticking to PLA.
Seeing you have amps in there, wanted to ask you what sort of filament are you using and what is your experience being so far?
Thanks a lot!

 

[KamuDesigns]

Hi @KamuDesigns , amazing project! I got my first 3D prints done a couple of weeks ago and learning on the go.
For electronics enclosures i am using PETG because I am afraid that PLA starts to soft if electronics get a bit hot and don't have a dedicated area to print ABS. But I am not finding PETG so easy to print, and worse than that, i am seeing that the dimensional stability is not great. Well, they are thermoplastic s after all. I wonder if it is worth the risk of sticking to PLA.
Seeing you have amps in there, wanted to ask you what sort of filament are you using and what is your experience being so far?
Thanks a lot!

This filament is matte high temperature pla that I got from anycubic surprise box. High temperature means that it's designed to withstand annealing, which is process I did not use so it's basically just matte pla+ that prints great.

What comes to temperature resistance you'd need the whole enclosure mass to be at least at 65c before it would be at glass transitional temperature. Obviously you would't use pla in sauna speakers or use those speaker in arizona garden party during summer. Otherwise it's not likely that any part of speaker reaches temperatures hot enough for it to turn soft.

Petg in turn isn't stiff enough for enclosures imo. You would have to use cf filled petg to gain enough stiffness.

Maybe a small travel speaker could do with plain petg... I have to try that to say for sure.

Also you'd need enclosed printers with at least 50c internal temperature for petg, abs, asa and other higher temperature filaments.

If you are printing smaller stuff like waveguides then you can just use draft/ooze shield to trap the heat and prevent warping.