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The Once and Future Theater - Page 21

post #601 of 1066
I've always liked big...... Wait..... Wrong forum. Those look awesome my friend!
post #602 of 1066
Thread Starter 
Thanks J_P_A! I think I can say that cabinet building has been a success. I can say it went as planned, and tentatively, with good results. There are still some edges and round-overs and whatnot to clean up before finishing can start, and obviously crossover building. I'll have those parts tomorrow, and with any luck (not likely) I'll make some noise with them by Monday.
post #603 of 1066
Thread Starter 
Oh, I almost forgot. I didn't realize that the kit would include screws. So I think I'll go with those for final assembly. I just want to make sure I do whatever I will want for poly-fill or anything else, since I won't want to remove the screws and trust them to hold well again.
post #604 of 1066
Careful Fred....your progress is showing!! tongue.gif
post #605 of 1066
Thread Starter 
You must not have noticed how I made sure the ceiling wouldn't be in image. I wouldn't want to illustrate how I still only have one sloppy layer of compound on the joints. I haven't done anything but build speakers in weeks!
post #606 of 1066
Fred,

You are almost inspiring me to tackle building my own cabinets, which would most likely be a disaster. (I live vicariously through following these threads). Speakers look great to me! Have you got pics of your crossover yet? Love to see them.

Edited to add, whoops, see you were just getting the parts on Friday.

Thanks!
Edited by Willie - 7/6/13 at 10:04am
post #607 of 1066
Thread Starter 
Willie, with a table saw it was easy! Without a table saw it might be impossible.

I soldered up the first crossover last night. I took a picture of how I laid it out, but I don't have any pics of the finished board yet. I didn't upload it, so that'll have to wait until tonight after work.
Edited by HopefulFred - 7/6/13 at 6:44pm
post #608 of 1066
Thread Starter 
Here's how I laid it out. I felt pretty confident in what I was doing, so I didn't bother posting it for anyone to review before I drilled holes in the board and soldered it up.

If you're a total crossover noob like I was (am), I'll explain for you what we have here. First, the schematic created and posted by Bill Waslo, over at diysoundgroup.com


My layout uses the same general positioning because it was easier to think about that way. So, following a tip I read somewhere, I created a large grounding strip from a bit of 14g romex I saved from demo. I laid that more-or-less down the middle to give me a convenient place to reach ground. Then , working from left to right across the top, just like in the schematic, I ran the series (in-line) components that lead from the amp input to the board (A+) to the tweeter output from the board (T+). Those components are (in order) the 20 microfarad capacitor, the parallel section of the 1.5 microfarad capacitor and 12 ohm resistor, followed by the 6.2 ohm resister. Feeding off that series set are two branches: the first comes after the first capacitor in the tweeter series and includes a 0.4 millihenry inductor and a 5 ohm resister; the second branch includes a 0.05 millihenry inductor and a 7.5 ohm resister. Each of those branches simply shunts portions of the signal to ground (that's as detailed as I can describe their function, unfortunately)

The woofer portion of the crossover is simpler. It begins at the same (A+) feed from the amp, and includes a 1.5 millihenry inductor in series. That's the big iron core fella - he acts (when in series) as a low pass filter. Branching off the woofer circuit is a single branch including another 20 microfarad capacitor and a 3 ohm resistor. You'll notice that it doesn't look like the last two components of the woofer section branch off, but they do (imagine that you are an electron working your way from the amp to the woofer - once you pass through the inductor, you can go to ground through the cap and resistor, or you can go to the woofer, from the connection at the bottom left of the board. Now you know everything I know about passive crossover network design (almost).



When I went to solder it up, I drilled holes through the board to run the wires through (If you look closely, you can see black sharpie dots). I wasn't sure why this was done, but I found it helped to hold everything in place and make working with the soldering iron easier - on the other side there are no components in your way. I marked the places I thought the holes should go and went and drilled the holes. Then I routed all the wires through and found that a couple things needed adjusting - so I drilled a few new holes. Some of the components have shorter wires and needed to be brought together. The inductors in the tweeter circuit got moved apart because it occurred to me that they were at risk of producing interference. Just now though, it occurs to me that I wasn't thinking about the woofer inductor at all - it may be totally too close to the tweeter circuit inductors. On the other hand, maybe it's not a problem... dagnabbit.

Here's what I did. I hope it's not seriously compromised. EDIT: IT'S WRONG! This picture doesn't match the component layout in the previous image - nor does it match the diagram.


My soldering work is not exemplary, I know. I used a standard rosin-core solder (60/40, 0.062 dia, 1.5 oz) that I bought from RadioShack about a decade ago. I used a 30W electric iron, I bought from the 'shack, that same day a decade ago. Once it warmed up (about 5 minutes), it seemed to work fine. I went ahead and added leads to go to the drivers and binding posts. Maybe that was a dumb idea. It seemed like a good idea to me. I used bits of some 16g wire I had leftover from demo again. You'll see more wood glue that should help prevent my accidentally tearing it apart while trying to install it in the cabinets.



This last photo shows the overall layout of the reverse of the board. You can see the red feed into the board from the amp (was top left in the image of the front, now is top right). The negative feed back to the amp is the black wire connected to the ground strip. The two green wires are negative for each driver, and the white at the top (marked T) is the positive feed for the tweeter.



So, if I didn't mess it up by putting the iron-core inductor too near the air-core inductor, then I'm okay and ready to finish the cabinets and install everything. If I messed it up... well, hopefully someone will tell me.
Edited by HopefulFred - 7/7/13 at 11:36am
post #609 of 1066
Thread Starter 
CheapThrillXO1_zps470d245d.jpg
Edited by HopefulFred - 7/7/13 at 11:44am
post #610 of 1066
Thread Starter 
I fixed the crossover, but I haven't taken a picture. I had to cut off the wire on one side, swing the cap over to the left, and solder on the top of the board. It just barely reached. I think it's fixed.
post #611 of 1066
Thread Starter 
post #612 of 1066
Nice! Thanks for posting the clip.

Makes me consider doing my own cabinets using my brother-in-law's table saw. Speakers are going into new home cnst later this year (allegedly), so I have time to wait for flat packs, should they become available.

My wife reminded me that my father, a carpenter, had a variety of finger lengths owing to saws. She was quick to point out I was his son AND a guitar player. She then gave her blessing to buy the flat pack or pay my brother-in-law to cut the mdf for the cabinets.
post #613 of 1066
eek.gif Wow! You really did get it done by Monday morning! That sort of thing never happens on AVS! There are supposed to be excuses, and photos of nearly fatal wounds (pronounced, minor scratch). But no, you're going against the grain and actually meeting a deadline!

Well played, my friend! Well, played.

So, what do you think? Have your ears been thanking you since last night? Do I need to order a dozen of these things? Come on man, we need details smile.gif
post #614 of 1066
Thread Starter 
It'd be no fair giving details. The drivers are held in with scotch tape! I ran a couple test tones through it to make sure I was getting output on both drivers, but I'm still not sure the crossover is actually right. The woofer is impressive. I have an unanswered question about one of my tweeters as well - I'm not sure if it's the one I hooked up or not.

I only hooked up the one, because I haven't finished the other crossovers. I decided I wanted to build the others on two boards each - separating woofer and tweeter - so I need to do some reconfiguring, but that's no big deal.

What I can say confidently is that output is strong. The dogs upstairs had a few things to say about my tests. We're hosting my sister-in-law's dogs for a few days, and they let me know they heard it.
post #615 of 1066
Nice! They passed the always critical K9 test. Good news so far smile.gif
post #616 of 1066
Thread Starter 
41LA-4yYJ1L.jpg

It's almost too bad I'm using the Graffic Eye in the theater. I may have to find a place for this in the lobby. Or maybe one of these others. http://www.uncommongoods.com/product/toggle-switch-plate
post #617 of 1066
Dude, that is so freaking awesome! You need to find something cool to do with it. I dunno, maybe turn on the popcorn machine or something. Maybe a curtain that opens in front of your screen.
post #618 of 1066
Maybe that linear motion could push the buttons of a four scene entry controller, or even a 1S off/scene 1 entry controller.
post #619 of 1066
Thread Starter 
Saving this link for reference. I haven't checked the color in person, but I think it's a good match. I wish I didn't need 50 feet of it.

www.lumberliquidators.com/ll/c/.Red-Oak-Stair-Nose-PRROSN38/10013339
post #620 of 1066
The last time I bought stair nosings, I got it from Lumber Liquidators. Any reason you're going with a prefinished one? You'd probably save a good bit by finishing it yourself. Although, if it's a perfect match for the wood, it might be worth saving the hassle.
post #621 of 1066
Thread Starter 
Not sure really. So far I haven't come across unfinished 3/8 nose. I'd prefer not to finish it, and it only makes sense to me that the flooring manufacturer should make all the trim pieces to match their floor, but that seems too easy so they don't do that.

Google shopping shows unfinished nose for about $3/ft, plus shipping. So I would save a fair amount, but it would probably cost me three weeks and $50 to mess it up myself.
Edited by HopefulFred - 7/11/13 at 4:01pm
post #622 of 1066
I used 3/4" and just ripped it to 3/8. It was pine and pretty cheap from the local lumber yard.

Tim
post #623 of 1066
Thread Starter 
I had a little difficulty with one of the cabinets. Somehow, one of the pieces was not properly secured and there was a gap. A little elbow grease with a blade or two, followed by some aggressive clamping got it handled.


Once that was done, I got the edges trimmed are re-rounded. No pics of that in particular, as I don't really have any camera adequate for macro shots, so just use your imagination. smile.gif

Today, I was trying to get some finishing going. I've decided to go cheap, but I still want them to look reasonable and be able to improve them later if I should need them nice enough to be visible. So I got some wood filler, some sanding sealer, and some flat black extra-durable spray pant, as well as some sanding supplies. The wood filler was something I had though about a fair amount. I know some people prefer bondo, but I went with what was supposed to be a "better" product. This Minwax High Performance wood filler gets my wholehearted DO NOT BUY recommendation. Not only do you have to mix hardener and be bothered by the fumes, as with bondo, but you get almost no working time and pay more in the bargain. The package says mix 16:1 filler to hardener and you get 15 minutes working time. You actually get about 5 minutes. This picture shows all the waste of the filler that I thought would be plenty and be use-able within fifteen minutes, as well as one of the reasons I was using it. Most of the seams and edges are good enough to sand and paint, but there are a few places where the flush-trimming router bit gouged the cabinet a little. I wasn't using any fence - just a bit with a bearing.


Hopefully the filler will be cured enough for sanding in a few minutes and I can get coat of sealer on the cabinets today.
post #624 of 1066
Are you planning to caulk the inside of the cabinets to make sure they're sealed up? It seems like I remember a very specific type of caulk is needed for speaker enclosures due to the gases released as some of them cure. I can't remember off the top of my head, though.

That's good to know about the filler. I'm assuming you made sure you had the mix correct? It's surprising you only got about 5 minutes working time out of it. Maybe they intend for you to mix just enough to fix one or two places. Still seems odd, though. If your cabinetry skills are anything like mine, you're going to need to fill well more than one or two places. Cut to match, paint to fit, you know wink.gif
post #625 of 1066
Thread Starter 
I didn't want to caulk them, but it seems prudent at this point.

I've never seen a requirement for a special caulk. I hope what I've got works, because I'm ready to be done with them and get back to building. Ideally I'll caulk and add some insulation tonight, as well as get a coat of paint on them.

I still haven't managed to find any firm recommendation for poly fill or insulation. I read some say that you only need it for subs, but I know others use it in monitors as well. I'm kind of shooting in the dark, just aiming for middle ground. I figured I'd line most/all of the inside with extra R13 I've got.

The rationale I read and understood was that the fill absorbs the back wave, allowing the lf driver to operate as though the cabinet were larger. This design should have an f3 around 65 hz, so while I want all the extension it has to offer, I don't need more. That said, I don't know if absorption is figured into the design/model that predicts that f3. The other thing is that intuitively, the fill should diminish cabinet resonances that could color the sound, and again I don't know what would be required. I've read a recommendation of 1lb poly fill per cubic foot, which I think is what Tim has in his sten IIs, but that seems like an awful lot, doesn't it?
post #626 of 1066
Here's an AVS thread on the topic of sealants and cabs. The issue in question is the acetic acid that is off gassed while the silicone caulk cures. It sounds like a highly debated issue, but my take away from that is just let the stuff cure for a week or so before you put the drivers in there.

I wish I could help with the poly fill question, but sadly I don't know much about it. I was under the impression that it was one of those things that didn't really have any drawbacks, but there are so few things like that I should probably be suspicious.
post #627 of 1066
Thread Starter 
Giving caulk a week to cure is no problem, so I'll do that even though PE says the woofer has a treated cloth surround - whatever that means. Thanks for the link.
post #628 of 1066
Thread Starter 
Quote:
Originally Posted by HopefulFred View Post

Giving caulk a week to cure is no problem, so I'll do that...
This was a lie. I did not caulk the inside of the cabinets. This afternoon, I got the first one stuffed with insulation and the crossover mounted inside, and the drivers screwed down. I fired it up, and everything was good. I knew it would be, because it was the same components I tested in the video from the other day. Then I went to position the next set of crossover boards in the next cabinet and found that some of the stranded wire was breaking loose from some of the solder connections. "No big deal," I think to myself. "I'll just fix those later and use the third set of boards today." So that's what I did. I connected everything in the second cabinet and plugged it in to the amp. ...no woofer. So I backed out the screws and swapped in the other woofer, hoping that I just had a bad VC on one or something - nope. Somehow I've bogarted the XO I guess. I'll take them both to work with me and see if I can figure out what I did wrong.

pretty disappointing.
post #629 of 1066
If some of the strands are breaking loose you need either more solder or more heat. There is no way anything should be coming loose.

The parts are largely immune to overheating. I would resolder.

Tim
post #630 of 1066
Thread Starter 
Thanks Tim. I figure that since I'm using a 30w iron, more heat could be in order. We'll see.
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