3d printed C-Note Speakers

[thompsbp]

Hey Folks. So last month I purchased and built the C-Note speaker kit from Parts Express with the wood knock down cabinets. My wife heard them and like them so much that she asked me to put them on the TV to replace an old sound bar that we had had for a decade and honestly just sucked. So I ordered the WIIM amp and an RSL Speedwoofer 10E and turned that into a nice little 2.1 system for the TV. This left me still needing speakers for my original use case, my gaming computer in my workshop.

I learned last time when I built the wood cabinets that wood working was really not for me. So I decided to cad up and print some cabinets with PLA.

Anyhow here is a link to the files if you are interested in taking a look...

C-Note Speaker Cabinet and Brace (Cut to fit on smaller printers) by Brayton Thompson | Download free STL model | Printables.com

But i wanted to come ask about their performance. I borrowed a UMM-6 off of a friend because he was interested in seeing how they compare to the wood cabinets i built. I took a quick measurement with the 3d printed version but i really dont know if i ran the test correctly or even know what i am looking at. I was hoping i could get some pointers here...

Attached is the measurement i took. ORANGE = 3d printed... RED=MDF (wood)

Here is some video i took on my phone. I know it wont be the best quality but i think it shows that there was nothing glaringly wrong that stood out to me...

Anyhow would appreciate any guidance anyone can give.

Thanks

 

[ppataki]

It would be great to see the other curves too (distortion, IR, step, etc.). Could you please share your mdat file? (you can upload it zipped)

Very nice initiative!
I also have the same Dayton tweeter and love it

 

[thompsbp]

It would be great to see the other curves too (distortion, IR, step, etc.). Could you please share your mdat file? (you can upload it zipped)

Very nice initiative!
I also have the same Dayton tweeter and love it

Absolutely... I will need to take a new measurement if you want to see one for the wood cabinet. I only took a screenshot of that one and forgot to save the measurement...


The other thing i guess i should add is that i am using the Arylic B50 amp. I asked Gemini and to look at the measurement and it thought that the brightness was caused by load dependency on the amp. Also this is just a 1 m in room sweep no special corrections or anything.

 

[soccermommy]

Nice design! What filament did you use? Wall and Infill settings?

 

[thompsbp]

Nice design! What filament did you use? Wall and Infill settings?

Thank you...

I used Elegoo Matte PLA Navy.

https://a.co/d/iDrLdk1

The settings are...
215 base layer
210 after that
No layer fan (to help prevent warping)
I also printed it in an enclosed tent again to help with warping since it's such a big print.

3 perimeter walls
10% gyroid infill
Default top/bottom layers
Fan to 50% for bridges.
Minimal paint on supports for the keys and slots used to join pieces. You shouldn't need much.
Mouse ears for corners.

The settings for the U Brace are different.
No top/bottom layers
15% honeycomb infill.
3 walls

 

[ppataki]

Absolutely... I will need to take a new measurement if you want to see one for the wood cabinet. I only took a screenshot of that one and forgot to save the measurement...


The other thing i guess i should add is that i am using the Arylic B50 amp. I asked Gemini and to look at the measurement and it thought that the brightness was caused by load dependency on the amp. Also this is just a 1 m in room sweep no special corrections or anything.

Thanks for sending the measurements - it would be great to see the same measurements vs the wooden cabinet too

Just some general comments about the measurement you shared:

1. FR looks pretty good (some mild EQ-ing would make it even better though), phase looks superb

2. Distortion is relatively high. I would be really curious to see this same graph for the wooden cabinet to compare with (at the same SPL)

3. Both the tweeter and the woofer seem to have inverted polarity (you can see that in the IR and Step response curves, their max is at -100% instead of 100%)

4. On the waterfall plot I can see some heavy room echo (at least that is what I suspect but I would be happy if others here could confirm that too)

 

[thompsbp]

Thanks for sending the measurements - it would be great to see the same measurements vs the wooden cabinet too

Just some general comments about the measurement you shared:

1. FR looks pretty good (some mild EQ-ing would make it even better though), phase looks superb

View attachment 500790

2. Distortion is relatively high. I would be really curious to see this same graph for the wooden cabinet to compare with (at the same SPL)

View attachment 500791

3. Both the tweeter and the woofer seem to have inverted polarity (you can see that in the IR and Step response curves, their max is at -100% instead of 100%)

View attachment 500792


4. On the waterfall plot I can see some heavy room echo (at least that is what I suspect but I would be happy if others here could confirm that too)

View attachment 500795

Thank you for looking at the test for me. It will be a about 10 days until i can get the measurement of the wooden cabinets. I am currently traveling and wont be back until Jan 11.

I am really surprised at the polarity thing. I guess I will need to open the speaker and make sure i didn't mess up the crossover wiring.
Distortion will be good to compare to the wood ones too.
I am not surprised at the room echo stuff. Its a gaming/ workroom with no carpet and a lot of hard surfaces like table/workbench.

I might need to add more bracing to the print. I designed some L braces that I can fit through the woofer cut out to help with that but i wont make any changes until i have the measurements for the wood one vs the printed one in stock config.

I will likely just need to make two new measurements to make sure that I get the same SPL for both since i was def messing with the volume while listening since i took these and do not remember what volume settings i had.

Thanks again. When i get back from travel i will make the new measurements and post them.

 

[thompsbp]

Thanks for sending the measurements - it would be great to see the same measurements vs the wooden cabinet too

Just some general comments about the measurement you shared:

1. FR looks pretty good (some mild EQ-ing would make it even better though), phase looks superb

View attachment 500790

2. Distortion is relatively high. I would be really curious to see this same graph for the wooden cabinet to compare with (at the same SPL)

View attachment 500791

3. Both the tweeter and the woofer seem to have inverted polarity (you can see that in the IR and Step response curves, their max is at -100% instead of 100%)

View attachment 500792


4. On the waterfall plot I can see some heavy room echo (at least that is what I suspect but I would be happy if others here could confirm that too)

View attachment 500795

ok new data...

I retook data for the 3d printed cabinet and the wood cabinet. There are four measurements.
3d Printed on the Arylic B50
Wood on the Arylic B50

3d Printed on the Aiyima A20
Wood on the Aiyima A20

Please let me know how things look.

 

[thompsbp]

So i did some playing around with the latest data i took. I noticed that large spike in distortion around 450hz. It exists in all 4 measurements both 3d printed and wood. I asked Gemini AI what it thought about it and through some further exploration Gemini thinks it is related to the port. Basically when I built both speakers I glued some foam mattress pad to the walls. This includes the ceiling of the cabinet. While this doesn't block the port it does touch and damp it. I had assumed this would be a good thing. But according to gemini it would change the characteristics of the port and could be the cause of the 450 hz spike in distortion. So i am going to open up the 3d printed one and remove the foam from there and take a new measurement to see if that makes it go away.

Attached is the build photo from the wood kit. You can see that the top foam will touch the pipe. Since I built both speakers the same way with the exception that on the 3d printed version the pipe in printed in place rather than being screwed in after the fact, then they should both be affected if that is indeed the issue.

 

[thompsbp]

ok the newest measurement. Looks like my in room AC unit was causing a lot of noise that was affecting the test. I disabled and it measured with the foam touching the tube removed. Looks like that distortion dropped from 3.5 at 450hz to 1.3-1.4 at the same freq.

 

[ppataki]

I have checked your new measurements in terms of 3D printed vs wood
They are pretty much the same!

The wooden cabinet has a slightly nicer impulse response but it can be a measurement issue too

I think we can safely conclude that 3D printed cabinets (if well done) can be as good as wooden cabinets - at least from an objective measurement perspective

 

[thompsbp]

Really happy with how these came out. For 3d printed they sound great to me and look decent too. The best part was not having to sand anything.

 

[antcollinet]

Same driver kit - concrete cabinet.

Go on - tell me you don't want to try. He even sells the 3d printable mold plans for $20 (ish). I'm tempted

(We can ignore the tie in with GR research )

 

[thompsbp]

Same driver kit - concrete cabinet.

Go on - tell me you don't want to try. He even sells the 3d printable mold plans for $20 (ish). I'm tempted

(We can ignore the tie in with GR research )

If I had any clue how to design crossover's I would definitely be playing with different form factors. But seeing as I don't I specifically set out to make the cabinet the same physical dimensions.

 

[thompsbp]

just a small update.

I noticed while playing with some EQ that I had a slight rattle/buzz in the speaker that i had taken the measurements on. I ran a sweep from 80-150hz at full volume since i had been playing with those frequencies in the EQ and sure enough there was a distinct rattle/buzz.

I opened the speaker up to check to see if i had damaged anything. And the voice coil looked fine to me and didnt make any noise/moved nice and freely when i manipulated it. So i replayed the sweep with the driver out of the cabinet and found the rattle/buzz was coming from the spade connectors that i had used. So I cut them off and soldered directly to the speaker terminals. The rattle is completely gone now.

However I am left wondering how this would affect the measurements i took before. I already returned the mic to my friend so i cant take any more.

 

[ppataki]

just a small update.

I noticed while playing with some EQ that I had a slight rattle/buzz in the speaker that i had taken the measurements on. I ran a sweep from 80-150hz at full volume since i had been playing with those frequencies in the EQ and sure enough there was a distinct rattle/buzz.

I opened the speaker up to check to see if i had damaged anything. And the voice coil looked fine to me and didnt make any noise/moved nice and freely when i manipulated it. So i replayed the sweep with the driver out of the cabinet and found the rattle/buzz was coming from the spade connectors that i had used. So I cut them off and soldered directly to the speaker terminals. The rattle is completely gone now.

However I am left wondering how this would affect the measurements i took before. I already returned the mic to my friend so i cant take any more.

If the rattle was audible, it must have indeed been visible on practically all the graphs
I am just curious how a spade connector can rattle though - can you please elaborate that part?

 

[thompsbp]

If the rattle was audible, it must have indeed been visible on practically all the graphs
I am just curious how a spade connector can rattle though - can you please elaborate that part?

Yeah so when i got the spade connectors they were so tight that i could not get them onto the speaker tabs. I got to the point where I was accidentally bending the tabs trying to force the spade connectors on. So I used a small metal piece to open them up a bit. I eventually got them loose enough to onto the tabs. However now they were too loose. I took my pliers and tried to crimp them down in place as hard as i could but it was still not a tight fit. As a matter of fact when i pulled the driver out they both popped off of the tabs. Thats when I decided to just solder them on.

 

[a4eaudio]

...I am just curious how a spade connector can rattle though - can you please elaborate that part?

Yeah so when i got the spade connectors they were so tight that i could not get them onto the speaker tabs. I got to the point where I was accidentally bending the tabs trying to force the spade connectors on. So I used a small metal piece to open them up a bit....

I think the confusion is terminology. Below, is a gold plated "spade" connector. It would attach to the inside of the terminal post with a nut and if it was actually so loose that it rattled, it would probably just fall off. Below that is a "crimp" connector which I think is what @thompsbp is referring to. (EDIT: the "crimp connector below can also be referred to as a "spade" connector, as @antcollinet correctly points out.)


Spade connector

Crimp connector

 

[antcollinet]

I think the confusion is terminology. Below, is a gold plated "spade" connector. It would attach to the inside of the terminal post with a nut and if it was actually so loose that it rattled, it would probably just fall off. Below that is a "crimp" connector which I think is what @thompsbp is referring to.


Spade connector
View attachment 507160

Crimp connector
View attachment 507159

The second are also spade connectors:

Spade Connectors | Free Next Day Delivery | RS

We have both insulated and uninsulated crimp quick disconnect terminals to provide fast and easy disconnection of electrical components and devices.

uk.rs-online.com

 

[thompsbp]

I think the confusion is terminology. Below, is a gold plated "spade" connector. It would attach to the inside of the terminal post with a nut and if it was actually so loose that it rattled, it would probably just fall off. Below that is a "crimp" connector which I think is what @thompsbp is referring to.


Spade connector
View attachment 507160

Crimp connector
View attachment 507159

Ahh yes. I have been using the wrong terminology.