No MDF for the grille frame. Too heavy. Too messy. MDF has a lot of nice properties, but tensile strength is not one of them. Nor ability to hold a screw. I will get creative with pieces and glue. Probably poplar in 3/4 with 1/4 plywood for bracing. I can make those cuts. The 3/4 thickness causes the brass trim to stick out about 1/8 inch. Consistent gap, it looks good and will be helpful removing the grille in the future.
As expected the grilles are the worst part of the project. I should never have thought I could reuse that fabric. Put in a bunch of staples only to have to pull them back out.
Does anyone have a successful alternative to staples for attaching grille fabric?
When I built a two-ply spandex projector screen, I used the plastic trim and rubber beading that you use for a screened porch. The "center" type of trim has two channels, one for each layer of fabric. That worked like a dream. Not applicable here, though. I had a though that a cut groove on the side of the grille, the proper size for that rubber bead, plus two thickness of fabric, would do the trick. Not enough room here I am thinking. Also, it would take a router at this point, and I don't have the proper bit. Also, there are some steel brads lurking in there now. Those grooves could be easily cut in advance on the table saw, when you are sizing up all the material.
I am not into the hot glue, except right in the corners.
When I built a two-ply spandex projector screen, I used the plastic trim and rubber beading that you use for a screened porch. The "center" type of trim has two channels, one for each layer of fabric. That worked like a dream. Not applicable here, though. I had a though that a cut groove on the side of the grille, the proper size for that rubber bead, plus two thickness of fabric, would do the trick. Not enough room here I am thinking. Also, it would take a router at this point, and I don't have the proper bit. Also, there are some steel brads lurking in there now. Those grooves could be easily cut in advance on the table saw, when you are sizing up all the material.
I am not into the hot glue, except right in the corners.
They call it a "spline". Really easy to work with if the groove is properly sized. I think it would work in wood.
Sorry, bit late to the party but I picked up a pair of these a while back and made them into a 3way by cutting out the front baffle leaving around a 1” boarder to mount a new baffle on the front bringing it up flush with the front. I then covered the box in walnut veneer and painted the baffle gunmetal and added some pin legs. I used a WO24P-4 which give close to Q=0.7 in a sealed box (approx. 40litre), Morel EM1308 dome mid and a matching Morel ET448 tweeter. I am using an active crossover which is only roughtly tuned using LR2 crossovers with minimal other filters at the moment as I haven’t got good measurements yet. When I do get some I will tweak the active crossover (Minidsp Nanodigi + 4x Khadas Toneboard + Rotel RMB1066) and possibly try my hand at a passive one as well.
Good luck with the project, these are a pretty good starting point if you don’t have the woodworking skills to build a box from scratch.
Good luck with the project, these are a pretty good starting point if you don’t have the woodworking skills to build a box from scratch.
Like the build, Ugg. They should sound great with the active crossover. That is way to new a technology for me.
Stapled Velcro for the grill. Period-perfect.
I was hoping to retain the vintage ascetics of the originals. What put me over the top was the brass trim. ???????. Down the rabbit hole I go, but I do think I can handle a staple job and get all the dimensions to line up. The hole gig with these things is the brass trim. They have a picture frame cut, and all the dimensions need to stack up to what they require. Outside-in. Inside out. No fudging it.
To keep the staples away from the contact points, I have shims of edge iron-on veneer. Paper backed. I believe the screw locations for the trim mounting can be lightly heated with an iron and will conform to the cloth and staples, making them stable and predictable.
Stapled Velcro for the grill. Period-perfect.
I was hoping to retain the vintage ascetics of the originals. What put me over the top was the brass trim. ???????. Down the rabbit hole I go, but I do think I can handle a staple job and get all the dimensions to line up. The hole gig with these things is the brass trim. They have a picture frame cut, and all the dimensions need to stack up to what they require. Outside-in. Inside out. No fudging it.
To keep the staples away from the contact points, I have shims of edge iron-on veneer. Paper backed. I believe the screw locations for the trim mounting can be lightly heated with an iron and will conform to the cloth and staples, making them stable and predictable.
Here is the screen spline system used in a projection screen. So simple. FWIW, this is two ply spandex, silver with white on top. It traps almost all of the light, and the silver helps regulate the white balance. Acoustically transparent. Mount the L, C, and R behind the screen. Where the are supposed to be.
That is about 125 diagonally.
That is about 125 diagonally.
No. Short answer. I am stuck at 3/4 thickness. I ripped these to 3/4 x 1 (actual) as it fit the drawings. The brass dimensions work out and the contact will be wood to wood, plus maybe Velcro or felt. Or screws from behind with a gasket . The stackup is a slight gap, which looks cool and intentional. Like the body gap on a car panel. And, it can be pulled back out.
Here is the grill build
Total Bush use of a table saw. Square and identical dimensions to a fraction of a millimeter. I had to make 20 of those angle braces. In case of scrap. Less than stellar work on the final cut that opened up the inside cuts to the holes that were drilled quite well. I did not have a machine that could do it, so hand work. I made a jig, but the tolerances got out of control.
Masking tape to hold the corners together.
Polished the brass up to a mirror. What you see is the back side. No polish there,.
Here is the grill build
Total Bush use of a table saw. Square and identical dimensions to a fraction of a millimeter. I had to make 20 of those angle braces. In case of scrap. Less than stellar work on the final cut that opened up the inside cuts to the holes that were drilled quite well. I did not have a machine that could do it, so hand work. I made a jig, but the tolerances got out of control.
Masking tape to hold the corners together.
Polished the brass up to a mirror. What you see is the back side. No polish there,.
I think you could still cut a rebate for your rubber strip without starting again the cuts would just cross over slightly in the corners
I could do that. A couple of nails need to get out of the way first.
I guess the way to approach would be to come up with a repeatable process and cut, then fit the spline to the cut. There are a couple of sizes. Set depth. Cut with one pass. Put a suitable shim on the fence and make a second pass. I would say two passes of the saw kerf would be plenty.
I guess the way to approach would be to come up with a repeatable process and cut, then fit the spline to the cut. There are a couple of sizes. Set depth. Cut with one pass. Put a suitable shim on the fence and make a second pass. I would say two passes of the saw kerf would be plenty.
Grille fabric arrived today. Two different colors. I am thinking black from PE. I am going to mock up a rabbet cut on the first grille and fit the screen spline. See how it works. If not, I can glue a strip in there and trim with a router.
Staples it is. The groove interferes with where the mounting screws for the trim will go. No fixing that. In the future, I will plan to use try screen spline approach.
I just need to not put a staple where a screw will go.
I just need to not put a staple where a screw will go.
Okay. I have been going at this off and on. Was on vacation for a while.
I finished one of the grills to the point where I know they can work.
I put the necessary bracing / flange so that the new baffle will have somewhere to seat. This is metric plywood, so everything is trickier.
Spent a lot of time on the baffles. The tweeter is a rounded square cut through. The midrange is a monster and requires a very wide diameter counterbore. Like 0.81. A rabbet bit won't cut it. The woofers have a wider flange than I expected at 0.71. I had to make templates for each driver and get a special template tracing bit from Klingspor. A lot nicer place than Harbor Freight. It took a ton of planning and patience, but I scrapped nothing.
The midrange requires a notch for the terminal connections. It is a sealed back and weighs a ton.
Then, the dry fit.
It all fits...
I finished one of the grills to the point where I know they can work.
I put the necessary bracing / flange so that the new baffle will have somewhere to seat. This is metric plywood, so everything is trickier.
Spent a lot of time on the baffles. The tweeter is a rounded square cut through. The midrange is a monster and requires a very wide diameter counterbore. Like 0.81. A rabbet bit won't cut it. The woofers have a wider flange than I expected at 0.71. I had to make templates for each driver and get a special template tracing bit from Klingspor. A lot nicer place than Harbor Freight. It took a ton of planning and patience, but I scrapped nothing.
The midrange requires a notch for the terminal connections. It is a sealed back and weighs a ton.
Then, the dry fit.
It all fits...
be really interested to see the measurements for the mid and what you think of it seems really good value for money .
you've made a neat job of it cutting the holes perfectly is a pain !
why couldn't the baffle sit on the original support would it have been too far forward ?
you've made a neat job of it cutting the holes perfectly is a pain !
why couldn't the baffle sit on the original support would it have been too far forward ?
Yes. I could not move forward at all. It would interfere with the grille assembly. This is more like furniture than a speaker cabinet. Such as 60s-70s builds were.
I painted the cut surfaces with Wood Strengthener, since MDF gets pretty particle board like once it is cut.
The midrange was the focal point of this attempt. It is massive, efficient, and has a wide frequency response. I have a crossover assembly from Taiwan that is -12 dB on the woofer and tweeter and -6dB on the midrange. Crossover points at 900 and 5000. The make is KAsun and the build quality for the money looks very good. Unusual crossover that I hope takes advantage of that huge midrange. I have another with -12 dB slopes at 850 and 5800. I will try both.
I painted the cut surfaces with Wood Strengthener, since MDF gets pretty particle board like once it is cut.
The midrange was the focal point of this attempt. It is massive, efficient, and has a wide frequency response. I have a crossover assembly from Taiwan that is -12 dB on the woofer and tweeter and -6dB on the midrange. Crossover points at 900 and 5000. The make is KAsun and the build quality for the money looks very good. Unusual crossover that I hope takes advantage of that huge midrange. I have another with -12 dB slopes at 850 and 5800. I will try both.
Point well taken. I have no means to measure the output at this time. I only have my ears and recordings that I know well. I haven't attempted a crossover in going on 20 years. It sure looks like the average joe has tools now that weren't reasonably available back then. Maybe I attempt a modification or a new crossover. DSP crossover seems to be the safe bet for tweaking something so unknown. I would need a measurement setup regardless. That would be a big step, and I would need a LOT of catching up