Jack 12 Horn Throat Grille

The Jack of All Trades pro-sound cabs.
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decostaj
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Jack 12 Horn Throat Grille

#1 Post by decostaj » Mon Mar 20, 2017 7:52 am

Has anyone used the wire hardware cloth for their grille ?
I'm wondering if it's going to rattle or buzz.

Am I supposed to PL the wire mesh to the legs on the window braces that lead to the Phase plug (center of the baffle) ?

also....
In the front of the horn throat, I've seen some members use a foam phase plug. Can this be any shape and size ? In the home stereo speaker building world, some claim minute changes in shape/size can adversely effect the sound. I just want something there to give it that "finished look" The full melded array will hide most of it but still I want it to look mean.

Thanks
JimD.
Hardware Cloth.JPG

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Drey Chennells
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Re: Jack 12 Horn Throat Grille

#2 Post by Drey Chennells » Mon Mar 20, 2017 8:42 am

decostaj wrote:Has anyone used the wire hardware cloth for their grille ?
I'm wondering if it's going to rattle or buzz.

Am I supposed to PL the wire mesh to the legs on the window braces that lead to the Phase plug (center of the baffle) ?
Yes secure everything, leave nothing to chance that could vibrate against eachother. Just be sure it doesn't expand too much to hit the cone/surround, spread a thin coat and use heavyduty staples as needed to hold the mesh/grille tight to the legs.
decostaj wrote: also....
In the front of the horn throat, I've seen some members use a foam phase plug. Can this be any shape and size ?
The most recent versions all use a specified phase plug, if you're unsure of this update your plans.
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decostaj
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Location: Meriden CT. USA

Re: Jack 12 Horn Throat Grille

#3 Post by decostaj » Mon Mar 20, 2017 10:02 am

OK will do as described on the wire grille.
Figured I'd ask first, would be a nightmare to dremel that wire mesh out because of buzzing.

Ah yes.... I should have been more clear about the phase plug.
The laminated plug described in the plans has been constructed as per plans for thickness and diameter, turned on a lathe to match the driver's dust-cap profile ect.

What I was wondering about was the cone/domed shaped plug on the front (not the driver side) of the baffle I see a few builds where they added a conical shaped plug to the front to dress it up.

I know it's shape and size "could effect" the sound, er correcting some cone ripple thing and pushing beaming up a bit.
I kind of don't think those theories apply for pro audio bass cab.. I'm sure I'm wrong !
but
I wish to add one, same diameter as the circle on the baffle, half inch longer than the horn throat and shaped like an airplane nosecone spinner P51Mustangish.
Just wondering if I'm gonna wreck the designed tone of the jack by adding one ?

Bruce Weldy
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Re: Jack 12 Horn Throat Grille

#4 Post by Bruce Weldy » Mon Mar 20, 2017 10:19 am

decostaj wrote: Just wondering if I'm gonna wreck the designed tone of the jack by adding one ?
No, probably not.....but it will make your cab look like a cheap, cheesy DJ box. You don't want those great bass tones to come out of a box that looks like it was bought at the car audio section of Wal-Mart, do you?

:mrgreen:

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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Bill Fitzmaurice
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Re: Jack 12 Horn Throat Grille

#5 Post by Bill Fitzmaurice » Mon Mar 20, 2017 10:55 am

decostaj wrote: Just wondering if I'm gonna wreck the designed tone of the jack by adding one ?
I tested it with and without, it didn't work any better with so it's not in the plans. I don't remember if it worked worse with it.

decostaj
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Location: Meriden CT. USA

Re: Jack 12 Horn Throat Grille

#6 Post by decostaj » Mon Mar 20, 2017 11:27 am

Years ago we had some old Kef's or somethin or other for FOH, with phase plugs.
To me no matter if I bought them a wallyworld THEY LOOKED MEAN ! and sounded fantastic !

Behind the full melded array and perf grill, I don't think it would look toylike (trash/treasure tomato/tom0tto)
anyways...like this >
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Bruce Weldy
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Re: Jack 12 Horn Throat Grille

#7 Post by Bruce Weldy » Mon Mar 20, 2017 11:29 am

decostaj wrote:Years ago we had some old Kef's or somethin or other for FOH, with phase plugs.
To me no matter if I bought them a wallyworld THEY LOOKED MEAN ! and sounded fantastic !

Behind the full melded array and perf grill, I don't think it would look toylike (trash/treasure tomato/tom0tto)
anyways...like this >

As long as there is no chrome!

:D

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."

decostaj
Posts: 33
Joined: Thu Jan 03, 2008 8:48 am
Location: Meriden CT. USA

Re: Jack 12 Horn Throat Grille

#8 Post by decostaj » Mon Mar 20, 2017 12:06 pm

LOL nooo Chrome's for the melded array.... err I'm kinda going "basic black" except for a BFM badge.
I'm sure I'll need approval from Bill to use a BFM logo on my dumpy build. :noob: haha I paid my 14 bucks ! I'm goin with it.

I started this build years ago, buying all my parts from L.C. (great to do business with BTW)
everything's done except the box.
So I'm sure I'll be posting more questions as I move along on assembling the Jack.

JimD.

decostaj
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Joined: Thu Jan 03, 2008 8:48 am
Location: Meriden CT. USA

Re: Jack 12 Horn Throat Grille

#9 Post by decostaj » Wed Mar 29, 2017 8:53 am

What radius (round-over) is recommended for the edges to use the metal corners ?

Not being a big fan of the plastic ones, I ordered metal.
I think I may have bought the wrong ones though. They look like they have a 3/4 R

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Bill Fitzmaurice
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Re: Jack 12 Horn Throat Grille

#10 Post by Bill Fitzmaurice » Wed Mar 29, 2017 8:54 am

The standard corner radius is 3/8 inch.

decostaj
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Re: Jack 12 Horn Throat Grille

#11 Post by decostaj » Wed Mar 29, 2017 9:54 am

I bought corners from Speaker Hardware. "corners that actually fit 1/2" ply boxes"
They recommend 1/2 R for their corners on 1/2" plywood boxes.
Am I not seeing the correct hardware on S.H. website ? The 1/2" corners they offer are the ones I bought.

I rounded over a corner 3/8" and back cut the point of the corner a bit.... it is close but not fitting.
I guess it will kinda pull down tight when screwed.

Thanks for the quick reply
JimD.

Bruce Weldy
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Re: Jack 12 Horn Throat Grille

#12 Post by Bruce Weldy » Wed Mar 29, 2017 10:36 am

decostaj wrote:I bought corners from Speaker Hardware. "corners that actually fit 1/2" ply boxes"
They recommend 1/2 R for their corners on 1/2" plywood boxes.
Am I not seeing the correct hardware on S.H. website ? The 1/2" corners they offer are the ones I bought.

I rounded over a corner 3/8" and back cut the point of the corner a bit.... it is close but not fitting.
I guess it will kinda pull down tight when screwed.

Thanks for the quick reply
JimD.
Metal corners are a PITA to fit.

The plastic chevrons are a much better fit and they stack and lock beautifully.

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."

decostaj
Posts: 33
Joined: Thu Jan 03, 2008 8:48 am
Location: Meriden CT. USA

Re: Jack 12 Horn Throat Grille

#13 Post by decostaj » Wed Mar 29, 2017 11:33 am

I'm new to building BFM cabs or any cab that uses !/2" ply.
Looks as though I will have to reorder some plastic corners...
but even stacking chevron corners on speaker hardware's site recommend 1/2" round over.

I have some paint on, sanding now then Durex.
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Bill Fitzmaurice
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Re: Jack 12 Horn Throat Grille

#14 Post by Bill Fitzmaurice » Wed Mar 29, 2017 12:14 pm

I don't know what speakerhardware sells, but I've always used Penn-Elcom plastic corners, 3/8 inch radius, and they work just fine with 1/2 inch cabs.

Bruce Weldy
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Re: Jack 12 Horn Throat Grille

#15 Post by Bruce Weldy » Wed Mar 29, 2017 11:07 pm

Bill Fitzmaurice wrote:I don't know what speakerhardware sells, but I've always used Penn-Elcom plastic corners, 3/8 inch radius, and they work just fine with 1/2 inch cabs.
That's what I do. But you need to sand the corner back some to get it tight to the front of the cab.

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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