Thursday, July 28, 2011

Sub Project: Lookin' Good

At last! Here they are in all their glory. They turned out much better than I could have hoped, and I just can't stop looking at them. I'll shut up now so you can enjoy the speaker porn.

I did take some quick measurements comparing these with my old subwoofer. I'm beginning to think there's some pretty heavy room interaction causing that peak at 50 Hz since it affected both setups (one of the MFW-15's is in the same position as the H100 was). I didn't add any offset to these measurements, and I tried to match the levels as closely as possible, so you can see that I don't lose any output at all from the switch to sealed from ported (not too surprising since I added a second sub). I did gain a lot of extension, though, which is what I was after.

I hope everyone enjoyed watching this process as much as I enjoyed carrying it out. I'll keep you up to date on any new projects I come up with, but for now I'm taking a break.

Tuesday, July 26, 2011

Sub Project: Almost There...

I finally managed to get through the finishing process. I know I had originally planned to put about 8-9 layers of topcoat on these, but it turns out they look pretty good after just three (and a fourth light one on the top and front). While I had them disassembled for finishing, I did a couple other things that I neglected to do the first time around.

The first of which was just because I had planned to open them up again, and that was adding bracing from the top to the bottom. I don't think it was an issue when I had them hooked up earlier, but I had the wood, and there was no reason not to. These things were solid as a rock before, and now they're even more so.

Next was something that I decided not to do at first, but ended up wishing I had done, and that was soldering the internal wires to the connector. The crimp on terminals I used didn't fit very well, and I was afraid they would come loose eventually. Now I don't have to worry about that.

I'll put up some beauty shots when they're fully assembled, and then do some more measuring when they're back in the system. I'm going to take the opportunity to compare these to my BIC Acoustech H100 (a ported 12" woofer). I'll do the normal frequency response, and try to work through some THD measurements.

Monday, July 18, 2011

Sub Project: Stain Sneak Peek

Here's a crummy photo of the freshly stained subs. They look a little dull right now, but the color is right, and it'll really pop once it gets that "wet" look from the topcoat. It'll be a little while before they're up and running again, since I'm looking to put 8-9 coats of wipe on poly on these, and I'll only be able to do about one a day. In spite of my amateur staining, I think they should turn out nicely.

Just a note: they don't look as red (or as blurry) in person. I'll do a better job of capturing the color once they're finished.

Friday, July 15, 2011

Sub Project: Stain Test

Well, it looks like I'll be able to start finishing the subwoofers earlier than I anticipated due to the availability of a place to let them dry once I start wiping toxic vapor-producing chemicals on them. Before I go ahead and slap some stain on these guys, however, I've been doing a few tests to find a color I like. Above are the results. The middle one is a mix of the right and top colors. At the moment I'm leaning toward the middle, closely followed by the right. If you have any opinions, feel free to let me know. I'll keep everyone updated on the progress, so stay tuned.

Saturday, July 2, 2011

Sub Project: Finished (For Now)

Finally finished (for now).

It's been a while since my last update on the project, since I got on a roll, and just ended up finishing up for now. The first thing I did since last time was to make the holes for the Speakon connectors I'm using. Since the drill bit I was using wasn't quite big enough to make the right size hole for the connector, I had to improvise to get it to fit correctly. First I made a hole in some scrap MDF, and widened it using sandpaper until the connector fit.

Then I used the flush-trim bit for my router and the template hole to cut the perfect size hole for the connector in each cabinet.

These connectors are nice because all of the electrical connections are inside the housing, so there's very little risk of shorting, and they also have a nice locking feature so the plugs won't fall out.

Next I added some bracing across the sides. Eventually I'll be adding some top-bottom bracing, but that probably won't be until I do the wood finishing in a few months. It hardly needs it, but it couldn't hurt.

I don't have any pictures of gluing the top and bottom on, but it was much the same as before. After everything was glued together I used the flush-trim router bit to clean up all the edges before moving onto sanding. Above is a picture of the gasket tape I used around the lip that the driver sits in. It just creates an air-tight seal in the cabinet.

I added a couple screws to the connectors to keep them from moving around. Eventually I'll get some black screws and use some glue on the connectors, but that will wait until after the staining and finishing since I'll have to remove the connectors for that.

I used a roundover bit on the router to clean up the edges a little more. It made a huge difference in the look of the speakers, and it turned out pretty well.

Before finally closing them up, I got some cheap pillows and ripped them open to get some of the polyfill stuffing for the cabinets.

The polyfill increases the apparent internal volume, and should mask some of the mechanical noise from the drivers.

And finally above you can see the finished product. The old subwoofer is in the background, and you can see it's quite a bit smaller. It was tough fitting the new ones in their final places in the small room.

The final assembly wasn't without its challenges. I made the mistake of screwing in the driver before testing all the threads on the hurricane nuts, and it led to some issues. Some of the screws locked up in the nut and actually forced it out of its hole. With the driver in, there was no way for me to hold the nut still so I couldn't remove the screw and the driver was stuck. Eventually I just had to use a hacksaw to cut off the head of the screw and push it through the top so I could remove the driver and install some new hurricane nuts.

And for your viewing pleasure, here are the subwoofers in their natural habitat in my room.

I still need to stain and topcoat the subwoofers, but that can wait, since I don't have any way to safely let the stain dry.

That about wraps it up for now. I'll be posting some frequency response graphs of these monsters in the coming days, so keep a lookout.