Large speaker build - Ambitious project and an excuse to CNC!

Long story short:

Before my CNC-days I built a set of Line Source (LS) speakers utilizing decent quality drivers with a low price tag. Kinda nice when you need 40+ of them… The cabinet was made very crude and simple with ordinary hand tools and no real experience. They do work extremely well though…enough so to warrant a mkII dealing with sub-par cabinet qualities in terms of cabinet resonance and appearance.

Fast forward to present day:
As I now have a CNC at my disposal I wanted to put it to good use. More specificly, do a recessed mounting flange and surface contoured front baffle with precision :slight_smile:

So Fusion360 is my go-to design enviroment and I made a model:


My CNC is limited in terms of X/Y machine area and the baffle way to long (2076mm to be exact) so tiling the carve process is my only option.
Here is my solution:
I made a 2nd board surface with side walls so my stock MDF sheeting stay parallell til Y-axis and I can shift the MDF incremently to do each “tile” with precision and accuracy.

Here you can see the first “tile” out of the machine, with pilot and guide holes shown:
The process is carve each segment out, lift and shift the MDF board according to pilot hole and repeat.

Since the full baffle have a top and bottom that is different compared to the middle ones I needed to split this into three groups, one for the top, four middle and one bottom. 6 tiling operations needed for one baffle and each tile represent about 30min of actual carve time. So 3hrs per full length baffle.

Once the baffles are done the CNC-part of this project is more or less done, but its apparent that I need to machine the stands on the CNC aswell :slight_smile:

Reason for sharing - hope to give some inspiration for larger projects or guts to try more complex processes, where CNC may only a part of the bigger picture. Its a tool, use it :slight_smile:
My hobbies / interests are diverse, and CNC is a big part of several of them as its capabilities allow me to do really cool stuff :joy:

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Impressive build. Looking forward to seeing the finished project.

Really like your solution to build an second wasteboard with “sides” to facilitate, and more importantly control the tilling process on such a large component!!!

Here is a quick video showing some machining.
Running 12k RPM with 6mm 1F tool and 2500mm/min (100ipm)
Depth per pass is <10mm

https://discuss-assets.s3.amazonaws.com/original/3X/8/2/8270b6ccdb4dfb436c84a4f81e96a95d65b6dc38.mp4

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Nice. I’m more interested in hearing about the speaker drivers and wiring setup. :wink: I hobby a lot in microelectronics and have built a few speakers, but always used purchased drivers. Any info you’d share would be welcome.

Thanks!

I am using a driver called Tymphani/Vifa TC09-18-8 which is a 3.5" fullrange driver. Its frame is square which makes it possible to line them up with minimum center-center distance. (which is important)
They are std 8ohm drivers and they are grouped in series (in groups of 4 drivers) / parallell (5 groups) to manage the overall impedance.

You can findsome source of some of my inspiration here:
https://www.diyaudio.com/forums/full-range/242171-towers-25-driver-range-line-array.html
http://www.roger-russell.com/ids/ids.htm

Earlier today I noticed a flaw in the machining of the first baffle, apparently a post processor/controller issue.
This defect was present at the same spot on each of the 6 “tiles” I had carved. Only one corner, upper right on each 2nd opening had this defect. Weird.


(Old damaged drivers used for trial fitting)

I did a new CAM and ran a test tonite of all the code (except surface contouring) and it worked out just as intended :slight_smile: Phew :slight_smile:

Todays effort, two complete baffles made ready to be surface contoured at a later time.

Apparently my Z-axis is starting to bog up, I experienced it stalling on occation. MDF create a lot of junk so I suspect the bearings etc need cleaning :wink: I reduced my max feed and acceleration rates to stay safer and managed to complete the whole carve. I was reaaally close to another burnt Makita though…but was fast enough to this - phew!

Each baffle is 2097mm long with 24 driver openings and mounting flanges:

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Surface contouring in progress :slight_smile:

A negative fixture jig was made to keep the precarved baffles aligned so had to test obviously, two sections done and here its prepped for the 3rd. One complete baffle = 6 sections (of 4 driver openings)
So far so good :slight_smile:

Screenshot of the negative ficture:

Baffle secured to the fixture, in preparation of the 3rd run:

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This is fantastic, well done! You should be proud of this! Perhaps upload a video of the finished product so we can hear it in action!

Thank you, at the moment I feel quite content :slight_smile:!

First baffle is finished, I was babysitting the machine during these operations as earlier attempts have been twarted by mechanical issues, ruined router etc… :sweat_smile:
Now I just need to get get the 2nd one done…

(Ignore ruined drivers, these are old and damaged drivers I use for test fitting etc)

This is my home theatre room with my mk1 linesource speakers, these are shorter and much simpler/lighter structurally. My current project design goal is a better sounding, greater capacity system with better visual appeal :slight_smile:

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Here is a relevant (not identical) schematic showing how these are all wired up.
In my case I wire two separated groups (Series/Parallell config.) per array = I need two amplifier stages per array.

My main amp is a 5-channel home theatre unit, and today I only use 2, with 3 left unused. By going with this config I can use a total of 4 stages, increasing power capacity :slight_smile:

If you take a 8ohm driver and use 4, making two groups of serially connected drivers, then parallelling these two (2x2), you are back at same load as the individual driver. Same can be done for 9 drivers (3Sx3P), 16 drivers (4Sx4P), 25 drivers (5Sx5P) etc.

Looks absolutely fantastic buddy! Well done! Bravo! I really like the way the face of the box is contoured. I have V Carve Pro so every time I see what is possible in Fusion 360, it makes me want to give it a shot to see what I can come up with. Your design work on these towers looks amazing, well done

Thank you very much, the bulk of the work is still ahead in time, but the first - and most important feature in terms of looks - is now all done :slight_smile:
They are not 100% but perhaps closer to 98%, ready for sanding/priming/painting.

I now also have my baseline for building the actual cabinet. Over the next week I´ll prepare the sidewalls.

V Carve is excellent for what its intended to do, Fusion360 is very different, but very good at what its supposed to do. And being free licence for non-commercial use is awesome :slight_smile:

Video of the final contouring operation, in slow motion: https://www.youtube.com/watch?v=5CnDa84v_IU&t=2s

2097mm tall and my largest carve to date!
Needed to break it up into 6 tiles for full length.

In total the carve was primarely done in 12 operations per side, but each operation could have different tool strategies like 2D Contour for cutout, flanges, finishing pass.
Also had to carve fixtures to ensure I would tile with precision, so not counting the flaws and failed carves it took 24 separate runs to get the job done… :sweat_smile:

CAM done in Fusion360 and used UGS 2.0 (Stable) as sender.

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Wowzers, the slow-mo video was cool, thanks for the upload. The only thing that I personally would like to see is the process in how they were designed in Fusion 360 to see how the software is used. This project has inspired me to finally give it a shot. I’ve been putting it off because I just don’t have the time to learn yet another program but I’ll suck it up to better my output on projects, having the ability to contour something like you did here is, to me at least, next level and could take my designs to the next level. If you’re interested in taking up the task, would you be willing to make a short video on how you created the contours for the face of your project? Doesn’t have to be the exact project, but just to show an example of how one would achieve such a result? It would be very helpful, thanks again for the uploads and keep us posted on the progress, I’d love to see your step by step process in how you finish this thing up. It’s going to looks amazing when it’s done, again, well done homie!

Here is a very quick video showing how the basic shape was done :slight_smile:
Its not educational, just showing one way to achieve what I went with.

The basic steps are:

  • Draw up all overall dimensions, of stock and objects which in this case is the mounting flange of the driver.
  • Use these shapes to extrude “material” on either positive or negative space. You can Cut/Combine etc. Fusion defaults to Cut.
  • Once the base shape is complete, add radius to the side edges. Play with radius until it looks good.
  • Extrude the flange dimension again to create the “lip” below the radius edge.
  • Multiply the single object along a line (in height) and create the front baffle array.
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very impressive… kinda wish I understood the audio thing… I just have the speakers on the TV ha ha ha

That was awesome! Thanks for the upload. I’ve since watched a couple of tutorials on Fusion 360 and it looks like it won’t be too difficult to pick up on. That we every informative, thanks again! :+1:t3:

No worries :slight_smile:

Getting F360 to do stuff is easy, but getting it to do what you want is what require a little more effort.

Last week not so much CNC but other stuff:

My DIY-mister in the role of vacuum support, so I didnt have to babysit it for 6x22minutes :wink:

The finished MDF baffles are being primed with epoxy, two layers:

After using a circle saw to cut the cabinet sides to size, a mandatory “what does it look like” had to happen, so clamped one up for a quick peak. Laying on the floor the size doesnt look all that, but once upright - boy it it tall :slight_smile:

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CAM screenshot of the top plate for the cabinet, with flanges. Quick 15min job on the CNC :slight_smile:

First cabinet glued up:

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