DIY 9.4.6 Build

[trevordj]

I ended up having to rebuild the remote turn on boxes using mechanical relays instead of solid state. Doing this simplified the box, no longer needing fans, it is now smaller at 2RUs instead of 3RUs.




I used a couple of these relays: www.mouser.com/ProductDetail/te-connectivity/t92p7d22-12/?qs=yqCSZZldoM1QGZIQwNNCBQ%3D%3D&countrycode=US¤cycode=USD

[megash0n]

I plan to look back thru here because I am planning to get one of these CNCs soon. I am considering building 4 new subs and a custom console for my gear. I figure using CNC will make this sooo much better. I am looking to build two Devastators and 2 Full Martys. I'm curious where you got your cut sheet info at and which subs you actually built. I found some cut sheet info for the Full Martys, but I would love some cut sheets that have all the grooves and slots carved in for the bracing to sit in, etc.

[trevordj]

Aug 16, 2020 14:13:08 GMT -5 megash0n said:

I plan to look back thru here because I am planning to get one of these CNCs soon. I am considering building 4 new subs and a custom console for my gear. I figure using CNC will make this sooo much better. I am looking to build two Devastators and 2 Full Martys. I'm curious where you got your cut sheet info at and which subs you actually built. I found some cut sheet info for the Full Martys, but I would love some cut sheets that have all the grooves and slots carved in for the bracing to sit in, etc.

I designed my subwoofers and cut sheets myself, everything was done from scratch. I measured the T/S parameters with DATS and used Jeff Bagby's Woofer box and circuit designer excel spreadsheet to model it. After I modeled the subwoofer, I used Fusion 360 as my 3D CAD program to design the cabinet. I then use a program called Cutlist Plus FX to provide a list of the parts I need to cut. Any parts I am cutting on the CNC I use Fusion 360's CAM to generate the g-code which is loaded onto my CNC.

I am not sure if the cut sheets/3d files are available for those designs. I would be surprised if they weren't given their popularity. Those files must exist given GSG audio makes the boxes, given they operate as a business I'm not sure they share that information or not but it would probably be work an ask after you get your CNC, it would definitely make things much easier.

[megash0n]

Aug 17, 2020 11:50:50 GMT -5 trevordj said:

Aug 16, 2020 14:13:08 GMT -5 megash0n said:

I plan to look back thru here because I am planning to get one of these CNCs soon. I am considering building 4 new subs and a custom console for my gear. I figure using CNC will make this sooo much better. I am looking to build two Devastators and 2 Full Martys. I'm curious where you got your cut sheet info at and which subs you actually built. I found some cut sheet info for the Full Martys, but I would love some cut sheets that have all the grooves and slots carved in for the bracing to sit in, etc.

I designed my subwoofers and cut sheets myself, everything was done from scratch. I measured the T/S parameters with DATS and used Jeff Bagby's Woofer box and circuit designer excel spreadsheet to model it. After I modeled the subwoofer, I used Fusion 360 as my 3D CAD program to design the cabinet. I then use a program called Cutlist Plus FX to provide a list of the parts I need to cut. Any parts I am cutting on the CNC I use Fusion 360's CAM to generate the g-code which is loaded onto my CNC.

I am not sure if the cut sheets/3d files are available for those designs. I would be surprised if they weren't given their popularity. Those files must exist given GSG audio makes the boxes, given they operate as a business I'm not sure they share that information or not but it would probably be work an ask after you get your CNC, it would definitely make things much easier.

I finally found the main thread for the Marty's and the Devastators. So, I have many of the cut sheets now. I just need to determine which versions I want to build and whatnot. I'll probably have to draw in the daddos (sp?) myself. I feel like those are a must because I don't want to use screws. I also need to talk to someone to see just how much effort that CNC is to put together, learn how to use and setup/cut. I'm looking at The LowRider2 as I'd like to be able to cut full sheets if it isn't a huge headache to do so. I don't really have a ton of interest in printing and have a good friend with a printer. Maybe I should ask him how big his printer cuts before I buy something.

[trevordj]

Aug 17, 2020 12:32:05 GMT -5 megash0n said:

I finally found the main thread for the Marty's and the Devastators. So, I have many of the cut sheets now. I just need to determine which versions I want to build and whatnot. I'll probably have to draw in the daddos (sp?) myself. I feel like those are a must because I don't want to use screws. I also need to talk to someone to see just how much effort that CNC is to put together, learn how to use and setup/cut. I'm looking at The LowRider2 as I'd like to be able to cut full sheets if it isn't a huge headache to do so. I don't really have a ton of interest in printing and have a good friend with a printer. Maybe I should ask him how big his printer cuts before I buy something.

When I built my CNC, the lowrider wasn't ready for prime time yet. I still haven't heard too much about it one way or the other. For me, learning to use the CNC was a huge learning curve. I was able to put it together just fine but then it sat unused for about a year because I didn't know how to do the CAD and CAM. It was just a big mental road block for me. I finally had a buddy, who is a retired Intel VP engineer, come for a few hours and we got everything up and running. He gave me the post processing file for Fusion 360 for MPCNC. I spent a lot of time just doing several iterations of my speaker boxes in Fusion until I got something that worked. Its one of those things where, until you know the end, you can't know the beginning. Once you know the CAM side then it changes how you do the CAD side, if that makes sense. Really I just had to fumble through the designs until I got something that works. Now I have my workflow down.

As far as modeling your dados yourself, I highly recommend you do it. Everything in CNC is having your model correct and it is good practice to start with something simple like that. I agree with your use of the dados as well, not only will it allow you to assemble without screws but it helps keep the box square during glue up. I used more dados in my front LCRs than I did in my subwoofer boxes and they were much, much easier to assemble square. For 3D modeling I highly recommend Fusion 360, it is a full featured CAD and CAM workspace and it is 100% free for DIYers and small businesses.

Is the MPCNC worth it? Yes, but not as a very functional CNC. It is a CNC that is not very stiff or strong to the point of being impractical. It is perfect for learning though. Once you have built a CNC from nothing to a working unit, you are good to use any CNC. I would never want to experiment on a bigger, more expensive unit without having the experience of fumbling through this unit. Although, maybe a more commercial machine would be more supported with fewer bugs and not need as much troubleshooting.

At this point, I don't use my CNC much. It is slow and and flexes a lot. I have an issue where one of the stepper motors gives up if I push the machine at all. Within the next year I am going to get a new unit, a full sheet size Axiom CNC but I need to get my business off the ground and profitable before I can do that.

[trevordj]

I am building another black box for my equipment rack right now. This one will be a simple rack mount power distribution box. I wanted a power distribution box that is rack mountable and has powercon connectors, I already have a commercially available unit with regular NEMA 5-15 outlets. I found this box that would work available for purchase but it is over $800 😳. I don’t like that the unit had power inlet on the front of the box too, I need everything on the back.

The plan is, every piece of gear in my rack that has an IEC connector will get a cable that is terminated with a powercon and plugged into my box except the subwoofer amplifiers, those will get plugged into their own dedicated 20 amp outlet, and the dbx venu 360 will get plugged into the remote box. Everything with a wall wart will get plugged into my existing power distribution box.

Right now I am just waiting on the powercon chassis mounts and a chassis mount circuit breaker. I took apart my middle Atlantic power distribution box and that’s all there is to it, outlets and a circuit breaker.

I also got some beefy bus bars to make everything easy to tie together. I did my usual epoxy weld nut trick to attach the bus bar to the box.

[trevordj]

I have been diving in head first with crossover design. The learning curve is steep but I am getting it. I have been posting on AVS forum and Parts Express forum and getting some excellent feedback. I think I have the theoretical process of working with different crossover simulators now. I need to get the drivers in my front speakers and take some measurements of them in my room. I was going to finish painting them first but it will actually be better to do with just primer, in case I scratch the cabinets during the process. I'm not sure the degree of interest in crossover design here so I will just post where I am with the simulation:





Don’t pay attention to the polar response/directivity. The tweeter will be horn loaded so this isn’t accurate. Also the woofer is only on axis although I could simulate its polar response. It will be much more accurate to just measure these directly.

Another part of this process is, I plan to have PCBs printed for the crossover I design for these speakers. I have spent the better part of the last week learning how to do that. I use Fusion 360 and they have recently integrated Eagle directly into Fusion 360 electronics. Wow, the learning curve is very steep. I think I have the process understood. The majority of the time is in assembling the local parts library. It took a bit for me to be able to 3D model the inductors, I couldn't find any air core inductors that would be used for passive crossovers in the built in libraries within Fusion 360. These are just some models, mostly a proof of concept that I can actually do what I want to do. Now I just need to finish my library. Eventually my goal is to have models for all crossover components in Parts Express, but that's going to take a long time.

[cwmcobra]

I love your willingness to dive into the unknown and learn how to do this stuff. Kudos!!

Chuck

[trevordj]

Alright, I was able to finish my rack mount power distribution. Once I get my equipment rack built it will keep everything nice and tidy. After I finish the front stage speakers I am going to build the rack before I finish the surrounds.












-Trevor

[trevordj]

I continue diving head first into passive crossover design. Based on some recommendations I received I am going to measure some less expensive drivers first to get the process down. With that goal in mind I designed a test baffle with my previously constructed Vifa XT25 in a SEOS-8 waveguide along with a Vifa NE180W-08 woofer I had on hand for a future project.















Woofer



Tweeter




I am going to get my measurements together and simulate a crossover for this test setup. I am then going to actually build the crossover and see how things look. I will need some spare crossover parts around anyway so all the parts I get for this test will be usable. So far, the results are promising. The waveguide really boosts the low end efficiency of the tweeter. It should work very nicely with the Acoustic Elegance TD8M used in the surrounds.


-Trevor

[trevordj]

I have continued getting comfortable with measurements, crossover simulation, and crossover construction. After quite a bit of testing I have completed construction of the the test speaker I have named “The Diversion.” I am about to wrap up this test project after trying out some additional crossover tweaks (namely to pull down the rising response above 10kHz a bit. I have to put together a set of subwoofer and then paint everything and then I have another couple secret speakers I have been working on that will go in my new business. I will have to take a break with the speakers for a bit after that as I need to build some doors, a desk, and a small cabinet for my business.

Have I gotten sidetracked? Yes but it’s all about the journey.

Here is what the completed Diversion cabinet looks like.




These won’t be living in my home theater, I am putting them in my 7 year old son’s room and he is pumped. The stand bases are filled with sand for added weight and stability and there is a speakon connector coming out the back of the bottom of the stand for a nice clean wiring setup.

[trevordj]

I never posted the crossover design and measurements of this speaker. Here it is:


Here is the sim and current crossover design for The Diversion.



And here is the measured FR and distortion at 1m. This is a gated measurement good to about 500Hz so don't pay attention below that. These have very nice low end down to about 60Hz but are intended to be used with a subwoofer.



The little XT25 does quite well in the SEOs8 waveguide. They are crossed in this design at 1300hz with very low distortion and they sound great. You would never guess you are listening to a $20 tweeter


-Trevor

[trevordj]

Ok, some updates. I have one final crossover to test still but I finished painting The Diversions tonight. I’ll get them down tomorrow and at some point I will color sand and polish them.


The speakers are a really nice house of Kolor lapis blue with ocean blue kosmic sparks pearl. I don’t remember if I said but these speakers are going to go in my oldest sons room (he’s 7). Because of this I will also eventually build some speakers for my younger son (almost 5).



To go with The Diversions I built a subwoofer. It is a ported design using dual Dayton RSS210HO-8 subwoofers. The box has a sealed chamber for a plate amplifier, I went with a SpeakerPower SP1-700. I’ll wire the subs in series for a final nominal impedance of 16 ohms. I have named this subwoofer The Zaibas sub, Zaibas in Lithuanian means lightning and that felt fitting for these.



For my older son this got the same lapis blue

[trevordj]

Some technical information on The Zaibas Sub design:



The design uses two Dayton RSS210HO-8 8 inch subwoofers in just under 2 cubic feet tuned to 30Hz with a 4" x 16" double flared precision port.

www.parts-express.com/dayton-audio-rss210ho-8-8-reference-ho-subwoofer-8-ohm--295-459

www.parts-express.com/precision-port-4-flared-speaker-cabinet-port-tube-kit--268-352

I designed this subwoofer to pair with The Diversion bookshelves to be run off a plate amp with about 125 watts. I like some of these smaller, more practical builds. It will be powered by an on board plate amplifier. I went with the US made SpeakerPower SP1-700.

www.madisoundspeakerstore.com/AMPS/SpeakerPower-SP1-700-Subwoofer-Amplifier

Because these will be for my 7 year old son I want him to experience good sound but I want to limit output. I will be wiring the subs in series for a 16 ohm nominal load which should yield about 125 watts from the SP1-700.

As always, I designed the subwoofers in Fusion 360. The design is pretty simple with a tall box, top firing port, a couple of braces, a sealed amplifier chamber, and a double thick front baffle with MDF on the outside and Baltic Birch as the inner baffle for added strength. The braces have dados to keep everything square and all the outside joints are locking miters except the baffle which is secured with rabbet joints leaving 1/2" MDF exposed that will be finished with a chamfer. The rear of the box is just a regular miter. Basically the workflow is assemble the top/bottom and sides with locking miters then put in the braces, the baffle, and the back. It makes assembly very easy.

[trevordj]

Ok, I have finalized the crossover for the Diversion. I ended up going with this:





They measure and sound fantastic!



2nd order distortion at the crossover point at about 95dB output is 0.2%, 3rd order is 0.04%. Distortion reaches a peak of 0.7% 2nd order at 2.2kHz.



I wish I could have gotten by with a less complicated crossover as these are on the pricey side. But I can't argue with results. I will be color sanding and polishing the cabinets today and then I will build the final crossover, put it in the cabinet and this is a wrap.

[trevordj]

I spent some time color sanding these today. I also did a quick flow coat of clear and these are done! I will let these cure overnight and then I will build the crossovers on a board and install the drivers and ports tomorrow.

I keep trying to capture the color on these but it’s hard to do. The paint is mesmerizing. The ocean blue metallic pearl on top of the blue paint give them a real sense of depth. This is the best I could do for now. I will try to get them in the sun tomorrow.



Also, just an update on the other subwoofer, not all ideas work out. The orange color was a bust. It looks like a construction cone. I am going to re-spray these in a color called blood orange:



New color:

[butchgo]

Looks really good!!!
You are very talented....

[trevordj]

Alright, The Diversions are 100% complete.



I also completed their complimentary subwoofer, The Zaibas sub



I am very impressed with the sound of them together. I have not tuned them or integrated them and they already sound fantastic. The little 8” subs pack some heat!

I am working on a DSP box and I will get them set up in my sons room next. I’ll get some details posted of this cool box I am building to go with these after I finish it.

[trevordj]

Well, I have made a lot of changes in the last few weeks. For the first time in about 10 years I will no longer have any Emotiva gear in my rack. I still have three amplifiers, an XPA-200 and two XPA-100s. I will use these to power the stereo systems in my sons’ rooms.

For my home theater room I sold my XMC-2, XPA-3, XPA-7, UPA-700, and UPA-2. I have recently acquired three Marantz MM7025s that I will use in my new business and at home I purchased the new Anthem AVM90 and three Anthem MCA525 gen 2s. They won’t be available until December so for now I am listening to TV speakers again.

I had to take a pause on building speakers as I am building a desk and a couple cabinets for the new business.



I also had to build some barn doors for the business. These things were heavy! They weigh over 200lb each. The contractor will be painting them so this is pre-finish.



Back to work!

[ttocs]

That's a nice simple design for the desk! Me like!