DIY SLA Pro Grills
Posted: Mon Feb 24, 2020 1:52 pm
This was a project I've wanted to do since building my SLA's. Leaving speakers exposed freaks me out, whether for home audio or outdoor pro audio. The latter is for obvious reasons. Recently I "found" an old air duct return grill from an office remodel that looked like perfect speaker grill material. It's about 1mm thick with 4mm diameter holes spaced 6.5mm on center, so pretty much the same as you can buy retail. Here's my first ever journey to build metal grills.
First, I laid both speakers on this 2ftx2ft grill to make sure I had enough. Yes, I did. Then I thought it'd be smart to make a template instead of marking up the grill with construction lines that'll make a general contractor dizzy. So on to my C.A.D. designing. The black outline is the actual cab dimensions that it just laid it on and traced it. The red lines are the grill dimensions to cut and bend so it'll end up flush and seat against the baffle.
Here's the templete cut out and bent to form my cardboard grill. (FYI a solid cardboard piece without any pre-formed creases makes life easier)
Ok, so that didn't fit because the cardboard is 3x thicker than the grill.
So I had to math and cut another that fit better after being bent.
So I laid it out on the grill and traced the cut lines. I was gonna use a dremel, but this was at night and in the basement, so tin-snips it was. Boy does it suck cutting metal with tin-snips. I cut/stabbed myself a dozen times at least. My cut lines were on the the holes, so that make it easier to cut a few inches then bend the scrap. To form the bend, I just used the 3/4" mdf table-top I was using. I lined it up with my bend mark and gently tapped the hammer against it going up and down the side. When I had it all evenly bent, I used a little more force to make a nice sharper and straighter angle. The whole times you have to make sure your bend is still on that line and your holes will line up. I didn't have a pic of this step, but you'll see it on the second grill further down.
Here's the first finished grill.
The next day I thought there has to be and easier way to do this. So what I came up with is another baffle or "die" or "negative" or whatever you wanna call it to form the grill around. Like how you's imagine a machine would have a mold that would presss the shape into. I just cut another baffle, but just short of the saw-blade kerf to fit the grill bends (14"x10" - 1/8" each side). With some scrap wood I now have a smaller baffle that fits inside the inset baffle. Next I laid the baffle on the grill and traced around it making sure the lines were on the holes and square. Then I drew another square around that for the bend and for how deep I wanted the grill to inset to make the front flush.
Yes, it's not evenly spaced all around, but that's the only way to line up with the holes to cut.
Then I took my hammer and started forming the bends
Now all corners are done and everything looks square.
After this pic I realized the grill was stuck to the wood. I didn't wanna bend the grill back to get it out, so I stuck a screw in the grill and punched the wood out. Lesson learned.
Now I have another pre-formed grill that with a little bending and effort fit right in and is holding tight. The white is kinda growing on me, but I'll probably paint it satin black later.
First, I laid both speakers on this 2ftx2ft grill to make sure I had enough. Yes, I did. Then I thought it'd be smart to make a template instead of marking up the grill with construction lines that'll make a general contractor dizzy. So on to my C.A.D. designing. The black outline is the actual cab dimensions that it just laid it on and traced it. The red lines are the grill dimensions to cut and bend so it'll end up flush and seat against the baffle.
Here's the templete cut out and bent to form my cardboard grill. (FYI a solid cardboard piece without any pre-formed creases makes life easier)
Ok, so that didn't fit because the cardboard is 3x thicker than the grill.
So I had to math and cut another that fit better after being bent.So I laid it out on the grill and traced the cut lines. I was gonna use a dremel, but this was at night and in the basement, so tin-snips it was. Boy does it suck cutting metal with tin-snips. I cut/stabbed myself a dozen times at least. My cut lines were on the the holes, so that make it easier to cut a few inches then bend the scrap. To form the bend, I just used the 3/4" mdf table-top I was using. I lined it up with my bend mark and gently tapped the hammer against it going up and down the side. When I had it all evenly bent, I used a little more force to make a nice sharper and straighter angle. The whole times you have to make sure your bend is still on that line and your holes will line up. I didn't have a pic of this step, but you'll see it on the second grill further down.
Here's the first finished grill.
The next day I thought there has to be and easier way to do this. So what I came up with is another baffle or "die" or "negative" or whatever you wanna call it to form the grill around. Like how you's imagine a machine would have a mold that would presss the shape into. I just cut another baffle, but just short of the saw-blade kerf to fit the grill bends (14"x10" - 1/8" each side). With some scrap wood I now have a smaller baffle that fits inside the inset baffle. Next I laid the baffle on the grill and traced around it making sure the lines were on the holes and square. Then I drew another square around that for the bend and for how deep I wanted the grill to inset to make the front flush.
Yes, it's not evenly spaced all around, but that's the only way to line up with the holes to cut.
Then I took my hammer and started forming the bends
Now all corners are done and everything looks square.
After this pic I realized the grill was stuck to the wood. I didn't wanna bend the grill back to get it out, so I stuck a screw in the grill and punched the wood out. Lesson learned.
Now I have another pre-formed grill that with a little bending and effort fit right in and is holding tight. The white is kinda growing on me, but I'll probably paint it satin black later.
