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Discussion Starter #1
When I began my journey into DIY speakers home theater, I became focused on meeting what the industry and THX has determined to be the baseline for reference volume levels. I know that is very loud, way louder than I'd ever probably listen to. But as an engineer I likes the clear-cut rules for loudness and distortion requirements.

After building some large, power hungry WMTMW towers (my build) a while back, I started realizing it was not feasible to use them and give each channel of my home theater LCR mains 250W EACH just to reach my goal (Don't get me wrong, the Dayton Classic Towers sound amazing for music).

I built an 18Hz Infinity Offset Horn Sub (not my build) and discovered what 150W and efficiency can do for dynamics and headroom.

I stumbled across high-efficiency designs using waveguides. I then realized that my solid 90W/ch Yamaha receiver could power an econowave to reference with power to spare. After much deliberation between many different designs, I settled on the Econowave SR Compact, designed by Zilch.

78 lbs of drivers and crossover components were delivered to my door today. Enough to build 3 speakers for my LCR mains.

It uses a Dayton PA310-8 Woofer:


and a Selenium D220Ti Compression Tweeter mated to a Dayton Audio H6512 Waveguide:


I have a box design I modeled in WinISD. 1.6 cu ft with a 55Hz tuning. I don't have screenshots of the woofer response, but there is no danger of over-excursion at anything close to to the wattage I'll be using.


Progress might be slow, but I'll keep updating. Next up, LOTS of mdf cutting!
 

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Discussion Starter #3
I recently got another project that jumped in front of the box building. So, in the mean time, would it be worth breaking in the drivers? I know some designs benefit from that kind of thing. Does it matter what frequency or to what excursion it's done for and for how long? Woofers only, I'd think, unless compression drivers benefit from it, too.
 

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Discussion Starter #4
Started laying out crossover components last night. 5 caps, 4 inductors, 4 resistors and an off-board l-pad. The most complex crossover I've done.

Schematic


Proposed Layout


Anyone see anything wrong with the inductor layout? Trying to keep it compact while making wiring not a pain.

I'll move forward with this unless I hear otherwise.
 

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Discussion Starter #5
Ok, moved on with the crossovers. I Decided to use 1/2" ply for the base. It's what I had on hand and is plenty stiff.

I modeled the components in Microsoft Visio and then printed the layout full-size.



I stacked the boards, put the template on top and I drilled up all mounting points and lead holes. 3 identical crossover boards.



Only had time to get one set of components mounted. Looks clean and for the most part keeps my OCD in check.



The terminal plate handles input from the binding posts, both driver connections and wires for the l-pad. I hope to get the others mounted tomorrow and maybe start soldering. Oh so much soldering...

Relevant Imgur album
 

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Looks great so far. I still have some 6" and 8" JBL square waveguides for a Zilch design. Just never got around to it. Nice to see this thread resurrect the Zilch designs again.
 

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Discussion Starter #7 (Edited)
Nice to see this thread resurrect the Zilch designs again.
I'm kind of surprised there aren't more builds of them. I understand they are older, though.

I've never seen such a large collaboration of testing and design in one thread. I've been intrigued by them for years.

I'll try and do them justice.
 

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You are off to a nice start on the crossovers.

I've built several of the Zilch ewave combos over the years. I think they required more of the "Y" in DIY than some folks were willing to invest.
 

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Discussion Starter #9
I had time to finish the crossovers last night. Soldering is my least favorite part of the whole building process, but if I have a plan and a repeatable process, it goes fairly smooth.

3 (mostly) identical crossovers.


And the soldering:


The only thing not included is the L-Pads. That's where the 1-2-3 connections come in to play. Just wire them up to the binding plate correctly and that's it.

Keeping things clean and laid out well made doing the wiring easier. The first one (top) took me a while since I was double and triple checking my connections and then copying it for the other 2 went quickly. 16 ga wiring, red for Positive, black for ground/common. This helped me follow the circuit diagrams and make sure my connections are right. I think a clean layout on the topside means more wire on the bottom.

I I'm 99% confident I got them wired up right, but the truth will be revealed when I get the boxes built and hook them up.

Up next is trying out a method to recess the waveguides into the baffle. I found THIS METHOD which I think I will use to make a test piece. It seems to be a good way tat doesn't involve buying more tooling for my router. The template/guide will be a little large, but it seems pretty straightforward. If you guys have any other ideas, let me know :)
 

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Discussion Starter #10
Time for an update. Due to the currently-limited space in my shop (other projects piling up), I had to wait for nice weather to do the cutting.



First real nice day here in quite a while, so I set up a cutting station in the driveway. All cuts were done with a Harbor Freight clamping straightedge and my trusty circular saw.



A full sheet and a half cut up in just over an hour. All parts shown here except bracing and the beveled port pieces. About 120lbs of mdf. These are going to be heavy.



Weighting and clamping up the double-thick baffles.

Relevant IMGUR Album
 

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Discussion Starter #11
Progress is slower than I'd like.

Finally got something more done worth showing.



Baffles finished. I know I said I was going to flush-mount the waveguides, but I got tired of waiting for good weather to do the routing outside (too much dust) and since these will be living in the shadows, they don't need to be finished works of art. They're purpose is to be heard, not seen.

If you notice, however, the recesses for the woofers have already been cut. They are only 1/4 inch deep at this point, which was also. At first, I was bothered by them not being mounted on the same plane. "Acoustic center" and whatnot. The length of a sound wave at crossover frequency is something like 10 inches, and at 20kHz, the wavelength is about an inch. I'm guessing having the waveguide 1/4" closer than the woofer won't do anything significant. Standing up or sitting, or sinking into the couch cushions has a bigger affect on driver position.



Rear panels cut for terminal cup and L-pad.







Never enough clamps! I can only do one box at a time like this. Brads can't help me here as they're not long enough to reach through the double-baffle.



I DO have more clamps, but they're babies. Crossover standoffs going on.

It was at this point that I realized I got ahead of myself and forgot to install t-nuts or hurricane nuts or some sort of threaded insert on the back of the baffle of the box I just glued together. Oops.

Relevant IMGUR Album
 

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Discussion Starter #13

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Discussion Starter #14
Long overdue for an update!

I apologize to all my loyal viewers. My faithful followers who have inspired, guided and encouraged me... /funny


All glued up and dried. Pilot holes at the ports. This is just before I used a long flush cut bit to go over all the edges.


I had to test one out to verify the crossover. Old faithful Yamaha receiver. Pardon the mess.


1/4 inch roundover on the ports. Even modeled at max power (something like 300W and almost 130dB) the port velocity stays in check. So the roundover isn't really needed (not like a small flare like this would do anything anyways), but it has aesthetic value.


All 3 stacked up, ready for filling and finishing.

Relevant IMGUR album.
 

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Discussion Starter #15
FINISHING!!


Forgot to document the all the sanding, filling and priming. Every time I build speakers, I SWEAR I will do a better job at finishing. On these, though, I was in a rush. An unwarranted rush. I used standard flat black interior latex paint. Dark like a ninja. In the end they came out okay, and I'll be happy with them in the shadows. These will be heard, not seen.

I almost lost one during priming, though. Had to catch a wet-primer covered box as it started falling off of my diy paint pyramid stand things. That freaked me out. Then I was covered in primer.


The backs. I made a mistake here that is hard to see. I put the paint on too heavy and the back on a couple have 'waves' or other runs. It bothered me at first. I really wanted these to come out exceptional, but I could not justify block sanding everything to make them flawless.


Darkened ports. I peeked in at every angle (except up) and couldn't see any exposed mdf inside.


First box finished. I needed to see one done after all this! lol

Need to fix some flimsy wires that broke at solder joints before I close up the other two.

Relevant IMGUR album.
 

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Excellent :D

Now take the extra screws, paint them black, and replace the others. You know you have a black rattle can for just such emergencies.

Looks like you are about ready to test fire them.
 

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Discussion Starter #17
Excellent :D

Now take the extra screws, paint them black, and replace the others. You know you have a black rattle can for just such emergencies.
Maaaaaaaybe...:D

I admit that I should do that. Part of me likes the bit of bling they add, but in a theater room, those are perfect little mirrors ready to catch the eye. I don't know when I'll get a chance to do that, but it is on the list before I bring them into the house.
 
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