HowieZ DR200 build

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howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: HowieZ DR200 build

#76 Post by howiez »

I'm filling in the buttcheeks today. I'll be attempting to make the (almost) square box version. Want to mount my speakons in there, or maybe a recessed dish with jacks in it, have not decided yet.
And don't panic, the foreground ones are just sitting there after belt sanding into submission. I'm glueing them flush like the background ones (nd the other cab, already back in house/heat to cure).
Phil Makraken
Phil Makraken

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Seth
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Re: HowieZ DR200 build

#77 Post by Seth »

:loler:

Phil Makraken

Bwahahahaha
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: HowieZ DR200 build

#78 Post by howiez »

Tweeters are all cut and cleaned up. Bill that tweeter jig is superb. I was about 1/32 proud on the first cut, so I just moved my fence a fuzz and re-cut my jig kerf. It was hard to get my tape in there when i glued the stops apparently. But after another run through, all the first sides cut great. Then it turned out the second cut was perfect at 2" by doing that. I thought i'd have to fuzz my fence back since I cut the slot first and glued the stops in relataion to it.

Same with the 45 miter, I had to sneak jup on it to get the 3-3/8 but I wrote the fence to blade measure on my jig for next time around.

Next time i'd probalby remove all the piezo elements first. two of my corner ones have melty crumbs of ABS rattling in them. I'm about to open them up to clean them out. Hope I didn't melt anything!
Jig before first cut
Jig before first cut
first four corners
first four corners
pile-o-piezos
pile-o-piezos
all piezos cut
all piezos cut

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Seth
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Re: HowieZ DR200 build

#79 Post by Seth »

Howie, you're moving right along! Looking good :thumbsup:

One thing I see; unless you plan to alternate the tab orientation, it appears you may not have cut deep enough. For the standard, by the plans construction, the blade must be high enough to also trim the screw bosses and screw heads. Otherwise, they wont glue up flat. The screw bosses stick out further than 2". If you do plan to do the alternate method, forget I mentioned it... Good to go.

You're really coming down the home stretch!
Last edited by Seth on Fri Dec 17, 2021 10:18 pm, edited 1 time in total.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: HowieZ DR200 build

#80 Post by howiez »

Seth wrote: Fri Dec 17, 2021 5:00 pm One thing I see; unless you plan to alternate the tab orientation, it appears you may not have cut deep enough. For the standard, by the plans construction, the blade must be high enough to also trim the screw bosses and screw heads. Otherwise, they wont glue up flat. The screw bosses are wider than 2". If you do plan to do the alternate method, forget I mentioned it... Good to go.
Funny you should say that Seth, I didn't in fact get high enough. I always thought people were complaining about the two that meet at the middle. They fit so I glued 8 pairs for one array. Then as I started setting them side by side I noticed the bosses are fat on some. I cleaned them up with a sander, but I still have two gaps I need to clean more. I ended up removing all the piezo elements, turns out I may have two bad ones. After cutting two rattled. I thought I had gotten a chunk of plastic in them. Turns out one was made on a monday, the missed clamping the entire diaphragm, so it was wrinkled/folded over and loose. The other one had a HUGE chunk of solder splash in it. We'll see, i'll test them at some point here. I was going to test them for polarity anyway.
Array pairs
Array pairs
You can see gaps in a couple here, they'll need some more massaging. I'll recut the other 16 to make sure that barrel gets trimmed more evenly than my hand clean up.
test fit with gaps
test fit with gaps

Bruce Weldy
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Re: HowieZ DR200 build

#81 Post by Bruce Weldy »

With piezos, always buy 6-8 extra and test 'em all before you start cutting. Some will be stronger than others. Weed out the week ones.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: HowieZ DR200 build

#82 Post by howiez »

Bruce Weldy wrote: Sat Dec 18, 2021 12:09 am With piezos, always buy 6-8 extra and test 'em all before you start cutting. Some will be stronger than others. Weed out the week ones.
Sage advice. I also wonder how many of the castings are bad. It just so happens my two that made noise also had molding defects inside the lens. The both had a shrink spot where it cooled too fast. There is a pocket the size of a BB pellet in one and the other is closer to a 6mm airsoft pellet sized pocket. I'm thinking i'll cut two new frames because it'll just irk me it's in there.
mold shrink
mold shrink

Bruce Weldy
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Re: HowieZ DR200 build

#83 Post by Bruce Weldy »

When I built two OT12s and 3 WH10s, I had so many to test that I built a little tester. Two solid copper wires on a little wooden frame. The wires were the width of the + and - on the piezo. Sent a 4k signal to the wires then laid the piezo on top. It was really fast to test them one by one. Pull out the weaker sounding ones, then go back to those and compare them to each other, keeping the best ones to marry with the good pile. You'll find some weak ones and sometimes some dead ones.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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AntonZ
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Location: NL

Re: HowieZ DR200 build

#84 Post by AntonZ »

I made a similar jig, somewhat more advanced. One pizzer permanently mounted. The other position is a plastic cup with two bare copper wires (solid) straight through the cup so I could push down a pizzer in the cup and it would be perfectly parallel to the known good pizzer that is permanently installed to the jig. The wiring I made such that not only I could test each piezo and thus sort out the ones that sound notably weaker or "different". Secondly, with a switch I could "add" the permanently mounted piezo to the sound of the tested piezo. Volume should go up when adding the second piezo. If it doesn't, something is wrong. The third goodie on my jig is a phase reverse switch. Some piezo's sound perfectly fine on their own, but are apparently wired the wrong way around. That would not be noticable when used alone, but in an array it cancels out with the piezo's above and below so you would not want to use it. The phase reverse switch allowed me to easily weed out the piezo's that are wired the wrong way around. The out-of-phase anomaly is rare but it does happen. I tested about one hundred over the years, I think I found 1 or 2 out of phase.

Not sure if I still have pictures of my jig, many years ago since I made it. If anyone is interested, I will see if I can find some.

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: HowieZ DR200 build

#85 Post by howiez »

Bruce Weldy wrote: Sat Dec 18, 2021 9:20 am When I built two OT12s and 3 WH10s, I had so many to test that I built a little tester. Two solid copper wires on a little wooden frame. The wires were the width of the + and - on the piezo. Sent a 4k signal to the wires then laid the piezo on top. It was really fast to test them one by one. Pull out the weaker sounding ones, then go back to those and compare them to each other, keeping the best ones to marry with the good pile. You'll find some weak ones and sometimes some dead ones.
AntonZ wrote: Sat Dec 18, 2021 12:18 pm I made a similar jig, somewhat more advanced. One pizzer permanently mounted. The other position is a plastic cup with two bare copper wires (solid) straight through the cup so I could push down a pizzer in the cup and it would be perfectly parallel to the known good pizzer that is permanently installed to the jig. The wiring I made such that not only I could test each piezo and thus sort out the ones that sound notably weaker or "different". Secondly, with a switch I could "add" the permanently mounted piezo to the sound of the tested piezo. Volume should go up when adding the second piezo. If it doesn't, something is wrong. The third goodie on my jig is a phase reverse switch. Some piezo's sound perfectly fine on their own, but are apparently wired the wrong way around. That would not be noticable when used alone, but in an array it cancels out with the piezo's above and below so you would not want to use it. The phase reverse switch allowed me to easily weed out the piezo's that are wired the wrong way around. The out-of-phase anomaly is rare but it does happen. I tested about one hundred over the years, I think I found 1 or 2 out of phase.

Not sure if I still have pictures of my jig, many years ago since I made it. If anyone is interested, I will see if I can find some.
I've been thinking of a way to test. A jig sounds like a good idea, if either of you have pictures or schematics. I especially like the phase test switch. I was planning on downloading an app I had seen somewhere. The guy has you cut an old headphone cord, plug it into your cell phone and put the leads on the tweeter. It listens to itself and can tell if phase is normal or reverse. Problem with that is, as Bruce mentioned, you might have one of a different level. I like the side by side comparison idea.

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AntonZ
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Re: HowieZ DR200 build

#86 Post by AntonZ »

OK, I will dig out my jig. It has been gathering dust for quite a while.

Currently I do not have a schematic right away, but I do understand that it may be a bit daunting for people with little knowledge of electrics. I will draw something for that as well.

Bruce Weldy
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Re: HowieZ DR200 build

#87 Post by Bruce Weldy »

How about that! I actually had some pics from my OT12 build back in 2011.

Looks like my jig tests for polarity also.....didn't remember that.....

So one piezo if attached to the jig, then the others are compared to that...
OT12 Build 034.jpg
OT12 Build 034.jpg
Attachments
OT12 Build 035.jpg
Last edited by Bruce Weldy on Sun Dec 19, 2021 10:36 pm, edited 1 time in total.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: HowieZ DR200 build

#88 Post by howiez »

Bruce Weldy wrote: Sun Dec 19, 2021 6:52 pm How about that! I actually had some pics from my OT12 build back in 2011.

Looks my jig tests for polarity also.....didn't remember that.....

So one piezo if attached to the jig, then the others are compared to that...
This is awesome, thanks!

howiez
Posts: 314
Joined: Sun Mar 16, 2014 5:23 pm
Location: Fox Valley, Wisconsin

Re: HowieZ DR200 build

#89 Post by howiez »

So I cut the second 16 again to make sure the screw bosses were cut all the way. Suprisingly only about half of them actually hit. Seems there are two molds or they slightly twist one mold when setting it up. The one of three screw bosses that would point to the opposite side of the array is not always at 12 o'clock. If you look close, some if the side ones that hit are right in line, and get shaved. Some are twisted/clocked enough they don't even touch. Anyway they are all cleaned up. Next I pulled apart the one joint that was really bad. I scraped at two others that were tight and opened up some clearance. I was temped to take my multi tool and just shave between them, but a utility knife did enough cleanup.

Fun fact i learned this week, if you glue PVC pipe together it does not 'melt' together like I thought. You can heat the joint to between 4 and 500 degrees F and pull the glue apart before the PVC melts or burns. So I tried exactly that, I used my heat gun, set at 500F and warmed the joint that had a gap. I was able to separate it, shave the boss, and heat it up a bit and push it back together. Then I just dabbed a little glue back on the back. My plan was to do the coats of PVC glue, and lo and behold my local menards has black ABS glue in the plumbing section. Not ABS glue for black pipe (ok it is for that), but it is actually colored black. It does not color match perfect, but I thought it looked nicer than the clear stuff (or orange I had) on the black plastic.
Gaps fixed
Gaps fixed
I used the black glue on the frames, and it wicked onto the wax paper in a few places where i was sloppy. I'm always sloppy, so it's all over. I'll probalby use my dremel and a little brush wheel to clean it up, and maybe spray bomb them black again. You may also notice some of my sides skewed at glue up. Somehow I got a wrinkle in the middle, and you can see a little wave to the 'mounting flange' Again, heat gun to the rescue. I lowered the temp a bit, between 200 and 500 on my gun, and wamred the offending joint. After 30 seconds or so, I could flatten/flush the pair. I would hold it for 30 seconds or so until it cooled. I was much more careful on my second array so the jig would keep it flat. I'm guessing my bosses hitting did that, pushing things around a bit.
Glue wicking on the wax paper
Glue wicking on the wax paper
I tried something I saw on the forums here as well. For the layers of glue on the back, someone had an alternate method. They took MEK and put the plastic 'sawdust' in there to make a paste slurry. I actually cut the trimmed strips into 1" lengths and dropped them in a glass jar and let them dissolve for a day or two. I was able to get it to about honey consistency. Then I could take a stick and drizzle a line of it, or kind of brush it on. I can't stress enough to wear a respirator, and I did mine outside/garage open for fresh air and to let the solvent evaporate. It is nasty smelling, but I liked how it coated. I did one side one day and let it cure 24hours to make sure it would even harden and not melt through. It turned out nice and smooth, and they seem very rigid. With that I did the other side, the middle and the whole second array. I made the paste a hair thicker for the second unit so It would dry quicker and not run. I might do one more coat up the middle since it ran downhill a bit.
coated backs
coated backs
Last update for the weekend, I wanted to cut my throat fillers to finish the cabinet insides. I made a small template out of a scrap of the 1/8 ply since my woofer is not the recommended one. I think I have plenty of clearance with the standard diameters.
Attachments
throat filler size check
throat filler size check

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AntonZ
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Re: HowieZ DR200 build

#90 Post by AntonZ »

Nice to see you found pics of your old jig Bruce! I still have mine, here's a few pics I took today. Some oxidation on the copper wires, other than that it seems in pretty good shape after all this time.
RubiconJig_01.jpg
Here's the complete jig. One known good piezo tweeter is permanently installed on the jig. The plastic cup fits the driver part of a piezo to be tested. The connectors on the jig contact the copper wires when you push a tweeter in the cup. The jig has a 1/8" jack plug, to be installed into whatever source you have available that produces white noise. A signal generator and amplifier can be used. I took an old FM transistor radio tuned between stations. Perfectly fine white noise for testing piezo's.
RubiconJig_02.jpg
Note the name, I baptized mine "The Rubicon Jig", named after forum member RubiconProSound. He came up with the original idea. You may find some of hist posts still archived here in some of the subforums.
RubiconJig_03.jpg
Note that the fixed reference piezo is marked 1. The cup is marked 2.
RubiconJig_04.jpg
The left switch toggles the reference piezo on/off.
RubiconJig_05.jpg
The right switch toggles the piezo in the cup on/off, either in phase or out of phase.

The way this is used:
  1. Switch 2 IN PHASE.
  2. Push piezo in the cup. It should sound almost identical to the reference piezo. If it is noticably off, the piezo is bad.
  3. Add the reference piezo (toggle switch 1).
  4. The pair should sound louder together than the single piezo. If volume goes down, the piezo in the cup is likely to be wired the wrong way around.
  5. If the pair together sounds weaker compared to a single: move switch 2 to the "OUT OF PHASE" position.
  6. If indeed volume goes up now, then it is confirmed that the piezo in the cup is wired out of phase. What this means is that the wires to the piezo driver are connected the wrong way around internally. Either throw it away, or reverse the wiring on this one.
Out-of-phase tweeters are rare, but it does mess up the performance of an array so I found it worthwhile to test every tweeter for correct phase.


Funny thing: the plastic cup was used by my children when they were young. Way back when I made this jig we had recently stopped using it. The oldest is now in university.

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