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| Re: 4 Pi Build in San Luis Obispo - Progress [message #95582 is a reply to message #93009] |
Tue, 03 May 2022 12:08   |
alexg
Messages: 17
Registered: June 2019
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Chancellor |
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Finally starting to make some progress...... I was hoping to post as I go but I tend to work in fits and spurts when doing these kinds of projects and although I found time to work on the speakers I fell behind on my posts and updates.
In order to recess the wave guides, I ended up using the same template strategy that "Roger S" used. Thanks "Roger S!" At first I tried to use my jig to cut the shape of the wave guide directly into the baffle but really struggled to get the corners right. The jig was great for cutting the general shape of the wave guide but didn't allow me to effectively address the rounded corners. So, I ended up making the template per Roger S using my jig and router and then routed the corners by hand. It took me a several tries to get it right but after a few attempts I finally got one that I was happy with. From there I used the template to cut the baffle. Worked like a charm.
For the woofers, I beefed up the back side of the baffle with an additional piece of wood per Wayne's recommendation in order to give them a little more "meat" to attach to. Using my jasper circle jig I cut a round disc approximately 16.25" in diameter using some ¾" cabinet grade plywood that I had lying around and glued it to the back of the baffle. I then cut the recess and hole for the woofer.
From there I attached the baffles and vents using clamps and kettle bells.
For the most part I am pleased with my results thus far however I would like to point out a few issues.
#1 - Even though I had the local lumber yard cut my sheet of MDF to spec, after gluing up the box and then attaching the baffle my speaker was not perfectly square with some parts slightly hanging out over other parts. I ended up using a trim router to clean things up.
#2 - I pre-cut the hole for my vent with the intention of using a trim router to clean things up and make the opening flush and square however I got little too aggressive with the jig saw and over cut the opening in a few spots and then allowed the trim router to get away from me a few times so I now have to go back and fix the problem areas with some kind of wood filler. You can see it in the photo below and in some of the other photos in this post.
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Attachment: Inside and Front.jpg
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Attachment: #3 - Jig #5.jpg
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Attachment: Recessed baffle after jig saw.jpg
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Attachment: Baffle with round disc JBL BAcker.jpg
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Attachment: Router cutting JBL hole.jpg
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Attachment: Woofer Ring Back.jpg
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Attachment: Router cutting woofer hole.jpg
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Attachment: Baffle clamps.jpg
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Attachment: Kettle Bell Vent.jpg
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Attachment: Vent Issues.jpg
(Size: 2.02MB, Downloaded 687 times)
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| Re: 4 Pi Build in San Luis Obispo - Progress [message #97165 is a reply to message #97162] |
Sun, 05 November 2023 09:38 |
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Wayne Parham
Messages: 18787
Registered: January 2001
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Illuminati (33rd Degree) |
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The cabinet is pretty simple - it's a rectangular box - so cabinetmakers don't need anything more to be able to cut and build from these plans. They're not like the 12Pi hornsubs, which really is a complicated build, and needs more detail in the drawing. But you're right that the simple plans do leave some stuff out. Most of my plans don't even show the amplifier connection panel - largely because some use Cardas binding posts but others use a different kind of panel - so but I usually just tell people to center them on the back panel, three inches up.
Same thing with the cross-brace. I just tell people to place a cross-brace between the woofer and tweeter. I suggest a pair of sticks make from the panel material, one spanning front to back and the other spanning side to side. Most people do that, but some make a panel brace. Either method works just fine.
The stuff that's important acoustically is shown in the plans though. The crossover schematic, the cabinet dimensions and the placement of the drivers, the port and the fiberglass insulation damping material. Those are important because they determine things like internal standing waves and the shape of the forward lobe and positions of the vertical nulls.
Stylistic details are left to the cabinet builder. Some make a plain box with drivers mounted on the surface of the baffle. Others cut a groove in the front with a baffle with a router so they can recess the drivers and mount them flush. When doing so, the baffle becomes thin so more support is needed. Most cut a round or square panel, glue it to the back of the baffle and cut through it. That effectively doubles the baffle thickness in the area it is needed. Some people paint their cabinets, others veneer them. Some people make grilles, and others don't.
To tell the truth, I've seen some really nice cabinetry displayed here. There are some really talented cabinet makers that have posted pics of their work here. I asked to borrow one of 'em, and hade a cabinet built just like theirs. It's now offered as an option on the three Pi model.
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