Hello, I have posted some about this on another forum, but I thought I would migrate to AVS Forums for the build since this is a more appropriate place for it. I will move over the build log so far so that you guys can see the full project in one spot. That means this first post is going to be a long one.
Since the forum limits images I will have to break it up.
My father and I enjoy working on projects. Recently we have been working on building stereo music-listening setups, but now are turning our attention to a full 5.1 setup for my home. This thread is to discuss the design of the system and to share its progress. At the time the build started, I was living in a small apartment so the listening room has changed mid-build. We planned for this so its not an issue.
Since I lived in a small apartment, we planned to build in this order:
-Surrounds using an original design (full range, to be used as temporary fronts while space is limited). COMPLETE
-10" Ported Subwoofer using an original design. IN PROGRESS
-Center Channel using the AviaTrix MTM center design, modified to fit visual style.
-Fronts using the AviaTrix MLTL tower design, modified to fit visual style.
The whole setup will be driven by the Denon AVR 1909 that we picked up used. This gives 7.1 support, manual EQ, and options for biamping or setting up a second "zone."
For budget, our goal is to build the entire 5.1 system (including receiver) for under $1000.
Our goal is to use a consistent visual style, stay in low-budget territory, and get great audio for home theater and ambient music while entertaining. Each speaker will incorporate maple and walnut finished in semi-gloss lacquer, and Vivvid+ metallic blue vinyl. I look forward to hearing feedback and constructive criticism.
The ION Mini Surrounds:
While they will serve 2.1 duty for now, they will eventually be used for rear surrounds due to the limitations of the full range small box design. The drivers will be the Dayton Audio RS100*4 4" Reference Full*Range Driver 4 Ohm. These will be driven with a 5.1 receiver. Full range was chosen to keep cost down (one less driver and no crossover parts) and to allow the boxes to be very small for surrounds.
We are somewhat worn out with the challenged of translam design, so decided to go with a more traditional box. Since we have a laser cutter and CNC available, I was not going to be satisfied with a plain box with rounded corners. This design can definitely be made without CNC assistance, but the CNC helped save us the effort of creating jigs and templates.Even simple cuts will be made on the CNC just to simplify the tools and process. I decided that a 3D-carved baffle and rotational feet would give the impression of more complexity but still only requires 90 degree joints. The initial mock-up reminded me of a TIE fighter, which is why I am naming the system the IONs (TIE = Twin ION Engine).
Next we had a short part of an afternoon so I decided to quickly design some magnetic grills to eventually go on the speakers to protect them from incidental contact. Where we live now, these will be in a high-activity area. The grilles were designed using 1/8" walnut laser cut in a hexagon design (somewhat similar to the TIE fighter windscreen). To mount the magnets and space the walnut from the actual driver, 1/4" acrylic was laser cut and glued to the walnut. Three magnets were mounted in the acrylic to match the spacing of the screwheads so it can magnetically mount to the screws. These took maybe an hour or two from first conception to finished product.
Fast forward a week and we finally had time to CNC cut the rest of the parts. We began with the baffles, which were machined from 3/4" solid maple.
We elected to use a straight cut bit to save tool changes and didn't use a particularly small stepover. For those unfamiliar with CNC, this means that the carved baffle has a stairstep look. We wanted the edges to be smooth, so I used a finishing sander to remove the stairsteps and leave the angles. This manual sanding process makes the final baffles less precise, but helped make the process faster. Here is a side-by side to show what the sanding did.
While sanding, we sent the CNC to work on the 1/2" baltic birch ply sides. I forgot to take photos of the feet/wings being machined, but they were cut from 1/2" solid walnut. It took us about 3 hours to get all of our parts machined and sanded.
Now we have all of the machined parts we need to assemble the speakers. We gathered the machined parts with the hardware, and made the short wire harnesses needed to connect the drivers to the binding posts. Also not shown, we quickly cut some foam-rubber washers on the laser. These washers will go between the wings and body to keep the body from rotating without having to use too much clamping force on the screw.
Getting this far, I couldn't resist quickly assembling them to test out these drivers. We just quickly taped the sides together using blue tape, and installed the binding posts and driver. We did our best to seal the cracks with the tape, but obviously painters tape doesn't make for a very rigid box. We joked that its a feature since the whole box feels like a passive radiator. Assembly took maybe 20 minutes. You can see how the wings will mount with machine screws, into threaded inserts on the sides of the boxes. When done, the body will be able to rotate some to suit the location they are placed. The body doesn't touch the ground, only the wings. I tried to design the pivot point to be at a location where the front-weighting of the driver and the back weighting of the speaker wire would balance well. The plywood will be glued together, sealed, and then covered in a metallic dark blue vinyl. This was chosen to allow the build to stay cheap, fairly durable, and easy to assemble. The maple and walnut will be finished to a glossy finish.
Here you can see the quick and dirty test setup. We hooked them up to a parasound stereo amp and tested out tracks we know well from Tidal. They don't sound how they will at the end due to the total lack of rigidity in the box, but our initial impressions are that these full range drivers sound good in the mid range, harsh in the highs with poor dispersion, and lacking bass. The bass is to be expected for such a small driver in a small non-ported cabinet and is not a problem since the sub should take care of what is lacking. In the sweet spot, these have pretty good imaging, but it is lost when you go only a few degrees off axis. When movie material is played we found that the dialogue was a little hard to isolate when there was also bass being played. We found that they sounded much better when DSPed to bump up 250-500hz and to bump up 3k+. The 250-500hz was especially noticeable in male vocals. Without the DSP male voices sounded thin. We are hoping that when the box is more rigid and a sub is mixed in, this won't be as much of a problem. Sound effects like lightsabers and instruments like horns and saxophones sounded particularly good with these drivers.
Including the test-assembly and an hour of listening, we are about 7-8 hours in (not including 3d design time, which is maybe another hour or two). I expect that the whole build will be completed in about 15 hours total.