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Old 22nd July 2013, 12:53 AM   #1941
Carlp is offline Carlp  United States
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Originally Posted by xrk971 View Post
Looking forward to seeing your build. So you will be doing it in foam core right? It goes fast.
Yes, of course!
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Old 7th August 2013, 04:26 AM   #1942
xrk971 is online now xrk971  United States
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How is the Pioneer Karlsonator in foam core coming along Carl?
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Old 7th August 2013, 06:51 PM   #1943
Carlp is offline Carlp  United States
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Originally Posted by xrk971 View Post
How is the Pioneer Karlsonator in foam core coming along Carl?
Hey X, it's not going...yet. Just after you did the work for me I've ended up very busy with work and family travel, but I hope to get re-started soon. Next week I leave again for a week and a half, then I'm back for the long haul. So I'm hopeful I'll finish something up in early September. Who knows, though? If it's easier than I'm imagining, I might be done sooner.

Carl
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Old 23rd August 2013, 10:37 PM   #1944
Carlp is offline Carlp  United States
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OK, back in the game. I'm starting to pull this together SLOWLY, but had a question for X.

You mention an "aperature or wing" and I'm wondering what you mean by that? Is that the curved opening on the front panel/baffle? Also, "the slot on the wing starts at 3/8" wide and 3 in from the end" (which I assume means starting 3" from the top based on your scaling). Assuming I'm right, the 12" original has the slot starting at the top at 1/4" wide. Is yours different just to handle the scaling which would make it very small?

Finally, you mention a "top vent piece." What do you mean by this? I see an internal structure that leaves a slot opening at the top, which in the original 12" appears to be 1 5/8" high and opens to the back chamber which looks a bit like a horn. Is that the vent you're talking about?

Many thanks again, X!

Carl
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Old 23rd August 2013, 11:04 PM   #1945
xrk971 is online now xrk971  United States
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CarlP,
Yes, the aperture and wing is the same thing. I guessed the aperture shape and slot width. You can experiment but 3/8 in works well. You will feel air pumping through the narrow channel and the thinner you make it the more bass extension there is. Easy to play with. The top channel that connects the back and front is what I call the vent. You have it correct. Good luck and looking forward to hearing about your progress. Which drivers are you using?
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Old 24th August 2013, 01:58 AM   #1946
Carlp is offline Carlp  United States
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Thanks, X. It'll be the Pioneer A11EC80-02F, 4.5" that you simmed for me. Will probably use a cap for protection on the lowest end, at least to start.
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Old 24th August 2013, 04:20 AM   #1947
Carlp is offline Carlp  United States
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OK, started cutting pieces tonight and glueing a few. One question. The driver baffle (the doubled panel) is only about 9.5" when scaled down by 0.67. Since the driver is 4.5", that means there isn't much between the two.

1. Does that sound correct?
2. Think I should further brace that panel, or will the doubling do the trick?

I notice that the original 12" driver version has that panel at 14", which isn't a ton bigger, so I suppose my measurements are probably OK, but I'm just wondering.

Thanks.
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Old 24th August 2013, 12:20 PM   #1948
xrk971 is online now xrk971  United States
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Carl,
There should be just enough room for the two drivers with a 1/4 inch gap between them. I brace the baffle to the internal divider after both are glued in place with a couple of braces to the sides of the drivers. I think I may have braced the baffle to the bottom panel too, look at the photos in the mini Karlsonator thread. In fact, you may want to switch to that thread for future discussions so folks can see what you are doing relative to the posted plans and photos. Of course post link on this thread to finished speaker from that thread. It sounds like you are coming along nicely and I can't wait to hear from you how it sounds. Bracing lots of panels wherever you think there is a large flat surface that is free to vibrate like a drum head. That will increase SPL from the main TL output rather than radiating out through the walls.
X
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Old 25th August 2013, 12:14 PM   #1949
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Lets have some photos as you progress.
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Old 26th August 2013, 10:59 PM   #1950
Carlp is offline Carlp  United States
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Well, I thought I'd post a few pics, but ended up finishing it today (kids are home and I needed to be too, watching over them). So here are a few pics of the build. Played it just briefly, and it sounds quite nice. No real low end (my test song is I Love You by Sarah McLaughlin, which has a low series of notes that is felt as much as heard, and that was a bit, um, thin), but the upper bass and mids are quite nice. As for efficiency, I wouldn't say they are especially high. I'd guess lower 90s (close to the same as my Pioneer BOFU in a Pass designed TL, just below the Karlson in the last two photos). Oh, and I didn't use the 700+uF cap yet. No trouble with excursion on my 1.5wpc SE Pentode amp (strapped to triode).

I had built a wood BD Pipes with these drivers (not optimized) and I like them a lot for mid range and above - vocals, etc. Even the bass is reasonable in them. I need to hook that speaker up and demo the two together to get a comparison. I suspect the Karlson will beat it pretty readily.

This was a complicated build, but pretty reasonable using foam core. I wouldn't have wanted to try it first with wood!

Many thanks, X. I'll post in the other thread too, with a link to these photos. Maybe more impressions when I get a chance to really listen.

A few notes: The build is rough, but everything is reasonably well sealed (except drivers to the driver baffle, which I hope to try later). I drew the arc of the vent baffle using a thin piece of wood bent to some approx measurements taken from the original drawing. Borrowed a technique from boat building, which I've done a small bit of. Lastly, I did not brace the driver baffle other than a single 1.5" piece between the two drivers (see second photo).
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