| Main > Project Announcements |
| Project BlueShift |
| << < (8/18) > >> |
| Alejo I:
I absolutely adore how clean everything looks. That control panel in particular is just *cheff kiss* |
| Lexiq:
--- Quote from: Alejo I on October 04, 2023, 10:27:51 am ---I absolutely adore how clean everything looks. That control panel in particular is just *cheff kiss* --- End quote --- Thanks Alejo! |
| Lexiq:
Subwoofer The Focal car speakers have good bass for their size, but after a quick test, it was clear that they really need to be matched with a subwoofer. As I'm already using car speakers, I needed to find a suitable car subwoofer, and after more research, settled on the Kenwood KFC-XW800F. At 8", this is a smaller subwoofer and is a good match for the Focal speakers in terms of power requirements and impedance. The carbon fibre cone is also a good visual match and looks nice without a grille. Positioning the Subwoofer The next question was where to put the subwoofer? In terms of available space, somewhere in the cupboard area at the bottom of the cabinet made sense, perhaps facing downwards. The problem with that was that while this area was currently empty, there will eventually be a PC in there, with potentially vibration sensitive components, as well as all the associated wiring. Even a small woofer requires a fairly large box so I decided against this option. I didn't really want to cut a hole in the base either. The next option, which I ended up choosing was to integrate the woofer and box with the central rear panel mentioned earlier in the thread. This panel is a solid mounting point and any structural weakness that may result from cutting a large hole in it should be compensated for by the extra thickness added by the subwoofer box and the subwoofer itself. Additionally, this panel is further from components that may be affected by vibration, and there is a large internal space behind it that would otherwise be empty. It does mean the the speaker will be facing backwards, but since bass is not directional, this shouldn't matter. Subwoofer Box Subwoofers don't work well if they are mounted like a normal speaker. They need an enclosure to generate pressure and to isolate the low frequencies emitted from the front and back of the speaker. The internal volume of the enclosure is important too, and each model has specific requirements. Another consideration is whether to build a ported box (with a hole) or sealed box (no hole). A ported box generally has louder bass and a sealed box has cleaner or tighter bass. A sealed box also requires more power to drive the speaker due to the higher maximum pressure inside the box. I decided to go with the ported option for louder bass, and to lower the power requirements for the amplifier. I was also worried about the effects of vibration on the rest of the cabinet and having a hole for the air to escape seemed like it might help with that. Starting with the volume specified in the Kenwood manual, I calculated the box dimensions, accounting for the fact that it also needed to fit behind the central rear panel. Subwoofer boxes are usually made from MDF, but plywood can also be used and I had plenty of it so I used that. The box construction is fairly simple. The side panels are attached to the front panel with wood glue and screws, and are also glued to each other. The rear panel is screwed into the back edges of the sides and sealed with an EVA foam gasket. The front panel has a hole for the woofer and is attached to the back of the rear central panel with screws. The rear panel has a hole for the speaker terminals. Cutting the Subwoofer and Port Holes This is a significantly bigger hole than the ones in the speaker panel - much too big for a hole saw. There are hole cutting tools available that will do larger diameters, but they're generally used for softer materials used in ceilings and walls and I wasn't confident they'd work well on plywood. My first approach was to use the jig saw and build a circular guide similar to the one I used for the control panel curve, but with a much smaller radius. This idea appeared to work well at first, but after checking the reverse side, I found that the blade had flexed significantly, resulting in a much less than circular hole. I made some adjustments and felt that I could get it right, by taking extra care, but the second attempt wasn't much better than the first. When everything is assembled, this panel will be completely hidden, but I still wanted a better result. This time, I worked by hand, staying just inside the guide line and while it still wasn't perfect, it was much better and it was possible to tidy it up with the router later. The hole for the port is much smaller and a hole saw can be used. The diameter of this hole needs to fit the port tube so it's a good idea to find a port first. Fortunately they were available at my local electronics store. The port is shaped and tuned so should improve the bass quality as well as provide a nice external finish. Cutting the Central Rear Panel This is an external panel and the hole for the subwoofer will be visible, so I wanted a clean cut. The radius also needed to be larger because it has to fit the whole speaker, not just the back of the basket. Additionally, I didn't want to cut all the way through for the larger radius. The reason for this is that it mounts the woofer flush with the surface of the panel, and has the advantage of requiring the subwoofer bolts to pass through both the panel and the box, meaning they not only hold the speaker in place, but also help to attach the box to the panel. The first step was to cut a circular slot of the correct radius and depth using the router and an 18mm bit. Another jig was required for this and was fairly easy to construct using the accessories that came with the router. The next step was to cut the smaller radius to match the hole in the subwoofer box. This hole would need to go all the way through, but it made sense to use the router again. I found that I couldn't adjust the router accessories enough to get the radius I needed, so I used a block of wood instead which worked well. This hole was a bit more difficult to cut than the slot. Partly because it needed to go through more material, and partly because once complete, the mounting point for the jig is no longer attached to anything and the router is free to move outside the radius. With both holes successfully cut, it was time to check the speaker fit. Unfortunately, the larger diameter was slightly too small. This was a problem, because having cut the hole, there was no longer a mounting point in the center for a jig. I could have potentially clamped the panel to another piece of wood and used that, but I decided that I could use another router accessory and use the smaller radius as a guide for the larger radius. This worked well and the speaker now fit perfectly. At this point, I was also able to use the hole in this panel as a guide to tidy up the hole in the subwoofer box. Again, another hole needs to be cut for the port. This time slightly larger to accomodate the extra width of the port near the external opening. My port also has fins around the top, so I also cut some small slots to accommodate them. Attaching the Subwoofer The subwoofer comes with mounting screws, but again I decided to use bolts (actually socket screws) and tee nuts, this time M6 instead of M5. The process is the same as for the stereo speakers, but the bolts pass through both the panel and box. I also made another gasket to sit between the speaker and the wood to form a seal and to (potentially) help isolate vibrations. Attaching the port was simpler. I'd cut the holes such that the port will be a pressure fit. It required a little force to seat it correctly, but once in place, I didn't need to use any adhesive. Amplifier This is probably a good time to mention the amplifier too. I found a compact 2.1 channel amplifier made by Dayton Audio that matched my speakers' power requirements and also supported Bluetooth input as a bonus. The advantage of using this over car amplifiers is that it comes with a standard power supply and can be plugged directly into a power board. It's also has a nice design, which is important because I want the amplifier to be located in the cabinet drawer for easy access. I'm not an audiophile, so there's probably room for improvement, but after testing all the speakers together, I was very happy with the result. |
| javeryh:
Yo this is crazy audio! |
| Lexiq:
Monitor and Bezel The next step was to choose a monitor and build a bezel around it. I'd made the decision early on to use an LCD instead of a CRT, and my original plan was to use a 24" 16:10 monitor. This fits nicely within my cabinet dimensions and gives a reasonably good screen size for ~4:3 aspect ratio games. In the years since I started my build, more options had become available and I decided to rethink my plan. Monitors with higher resolutions and refresh rates were more prevalent, but they were all 16:9 aspect ratio, which meant I'd lose vertical screen size. Larger sizes were slightly too wide for my cabinet, and mounting them vertically (rotated 90) wasn't practical either. At some point, I came across the EV2730Q by EIZO with a square aspect ratio and a resolution of 1920x1920 at 60Hz. It's not a gaming monitor, but the specifications indicated a reasonable response time, good viewing angles, and good colour accuracy. The advantage of a monitor like this is that the 4:3 screen size is much larger than a 16:9 monitor of the same width. Additionally, it will play vertically oriented games (where the screen was rotated 90 degrees in the cabinet) at full height, which is an even bigger gain compared to the 16:9 monitor. It will also play more modern games like pinball at it's native resolution, meaning the table takes up the entire play field. In the end, I decided the size and versatility were worth the trade-off of lower resolution and refresh rate, and I haven't regretted that decision so far. One additional downside was the price. It's an expensive monitor, but I decided that I'd put enough time and energy into this project that it was worth it. One additional note: since purchasing the EIZO, LG released the 28MQ780. This monitor isn't quite square, but pretty close, has a higher resolution, and is less expensive. I'd have to mount it rotated 90 degrees to fit it in my cabinet, but if it had been available at the time, I would have seriously considered it. Glass Screen A glass screen in front of the monitor and bezel gives a cabinet a really nice finish. Clear acrylic is an option too, but I decided glass would be more durable and not prone to flexing. I spent a bit of time reading about tint levels, but eventually decided on 5mm thick untinted tempered glass. I don't really need to hide anything behind a tint, and it means I can run the monitor at lower brightness. Constructing the Bezel The bezel will hide the monitor surrounds and the space between the monitor and the cabinet. It's front and center of the cabinet so it needs to look good. With the square monitor, my bezel needed to be quite narrow, especially at the top and bottom, and I decided that plain black was the best option. My initial plan was to use 3mm black acrylic mounted between an 18mm plywood frame and a pane of tempered glass, all held together by slots in the cabinet sides. The monitor would be VESA mounted via a bracket connected to the frame, and the monitor's own bezel would be covered by the acrylic. This worked quite well, but I wasn't satisfied with the results. I used a very small (3mm) slot cutting bit in the router to cut the screen sized hole in the acrylic. The cut was not as clean as I hoped, and it was difficult to improve the finish with sanding. Additionally, when I tested the assembly in the cabinet, the interaction between the glossy acrylic and the glass, when squeezed together caused a type of thin film interference which resulted in very noticeable patterns. My revised plan was to use plywood and glass only. This would mean the bezel would require some more complex routing, but wood is easier to work with (and easier to repair small mistakes) than acrylic so I was confident that this was the right approach. It would also mean that I'd need to paint the bezel, but that was a problem for later. After cutting a correctly sized panel for the bezel, I routed a screen sized square on one side using the 3mm slot bit, to a depth of about 5mm. This process was similar to cutting the acrylic, but I didn't need to go all the way through. It was also significantly easier because plywood doesn't flex like thin acrylic. The next step was to turn the panel over and route an 18mm slot in the other side, with the outside of the slot describing an area slightly larger than the physical size of the monitor. This slot is cut to a depth of ~15mm so when it intersects the 3mm slot, the wood in the middle of the panel is freed. The result is a 3mm thick ledge for the monitor to sit against that covers the monitor's surrounds, but not the screen. One additional slot is required in the bottom ledge. This is because the monitor has a row of buttons along it's lower frame that protrude slightly from the surface. This slot provides space for the buttons so they aren't pressed by the bezel. Because the monitor controls aren't easily accessible, it's important to configure any monitor settings before it's mounted. Most monitors will sleep when they stop receiving a video signal, so if the monitor is powered on before mounting, it will wake and sleep when the connected PC is switched on and off. Mounting the Monitor The simplest way to mount the monitor is to build a bracket from plywood that attaches to the monitor's VESA mount and to the back of the bezel. I used socket screws and threaded inserts (again for easy disassembly) to attach the cross member with the VESA mount to the bracket mounts. The bracket mounts are attached to the bezel with wood screws. To ensure the monitor was centered correctly during final assembly, I positioned cardboard shims around the outside of the monitor before tightening everything. Cabinet Mounting The bezel and glass are mounted in 18mm wide, 5mm deep slots on either side of the cabinet. This hides the edge of the bezel and glass from view and creates a nice finish around the edge of the screen. Additionally, the bezel is attached to the cabinet sides with ledger boards in the same way as other panels. To fit the bezel and the 5mm thick glass into the 18mm wide slot, it's necessary to route a 5mm inset along the back of both sides of the bezel. A slotted footer made from plywood is used to finish the bottom edge of the bezel and is attached with wood screws. The front of the footer is angled to lie flat against the back of the control box when assembled. The top edge of the screen fits into another slot in the trailing edge of the speaker panel. My bezel design wasn't fully formed when I cut the speaker panel, so the slot is actually an inset that doesn't fully surround the glass and bezel, but it's not visible from the outside of the cabinet and doesn't make any practical difference. |
| Navigation |
| Message Index |
| Next page |
| Previous page |