Makes sense to me, just wanted to be sure I was understanding. There's an entirely new language to learn here!
And sometimes the guy offering help doesn't use the right language... D'oh!
Sorry for the confusion. 😱
As mike points out, the recess that a driver basket sits in so as to be flush with the baffle to reduce early diffraction effects from the edge of the bevel.
Ths term, for me is from the KEF drivers i sold in the late ’70s. It likely pre-dates that by a long while, it was the word used with the template/drawings they provided for the rebates. The British word (i assume) has become the common one for describing it.
dave
Elmojo,
If you can't cut a recess, I can do a couple of baffles for you according to the drawing Dave linked. I have some extra maple plywood from a pair of speakers I'm currently building.
Mike
If you can't cut a recess, I can do a couple of baffles for you according to the drawing Dave linked. I have some extra maple plywood from a pair of speakers I'm currently building.
Mike
Well, I thought I had it! 😱
From the description and photos Mike posted, it appears that the recess is the front side cut and the rebate is the back side cut, but what you just said makes it sound like you're saying the rebate is the cut on the front of the baffle that the driver sits down in. 😕
Thanks so much for the offer! I'm gonna give this a try myself, but if it all goes pear-shaped, then I may take you up on that. 🙄
OK, my bad. I was calling the back cut the rebate. I'll just use recess instead and chamfer or bevel for the back of the baffle.
The names are less important than the cuts themselves. Unless you're trying to explain things...
Ok, I think I have it now. That makes sense, since another word for rebate is rabbet in the woodworking world.
As you say Mike, as long as we all know what were talking about, the names aren't critical, but I'm learning from scratch so I figure I might as well learn it right the first time. 😉
As you say Mike, as long as we all know what were talking about, the names aren't critical, but I'm learning from scratch so I figure I might as well learn it right the first time. 😉
Ok, durr. Sometimes I shock myself with how dense I am. I'm lying in bed this morning, and my eyes pop open with the thought, 'hey dummy, you have a laser cutter! Use it to layout out the cuts for the front baffle.'
I sketched it out this morning, and I think that's going to make it way easier to cut precisely. Being 1/2" plywood, it's probably not safe to try to cut it completely with the laser, but I can at least trace out the lines accurately and score the center point for drilling and such.
I also have an idea for a super simple circle jig for my router table, but I need to think about that one a little more. Since I haven't sen this design anywhere before, I assume there's a reason why it doesn't work very well. 😉
I sketched it out this morning, and I think that's going to make it way easier to cut precisely. Being 1/2" plywood, it's probably not safe to try to cut it completely with the laser, but I can at least trace out the lines accurately and score the center point for drilling and such.
I also have an idea for a super simple circle jig for my router table, but I need to think about that one a little more. Since I haven't sen this design anywhere before, I assume there's a reason why it doesn't work very well. 😉
So as the morning beverage is kicking in and I'm beginning to think a bit more efficiently, it occurs to me that I have some cool looking 4.3mm (0.17") thick dark bronze smoked acrylic that might be a nice option for the front baffle. I can cut it completely on the laser, no problem. Other than figuring out a good way to affix it to the enclosure, and the slight change in internal volume, are there any negatives (or positives) to using acrylic instead of wood for the front baffle?
It's pretty thin, so you could put it over top of the baffle. Cut the recess shallower in the plywood so the thickness of the acrylic can be part of the recess. If the driver needs .25" of a recess, cut the recess in the plywood .08".
As far as affixing the acrylic to the plywood, I'm not the guy to answer that. But it certainly could look very nice!
As far as affixing the acrylic to the plywood, I'm not the guy to answer that. But it certainly could look very nice!
I was thinking of using the acrylic instead of the plywood front baffles, since it's simple to laser cut, wouldn't require a recess, and probably wouldn't need the rear bevel either. If it does, I can cut that easily on my router table or even by hand with a rasp.
Even though it's thin, this stuff is really stiff. Certainly not as stiff as the plywood, though, which is why I asked if there's a problem using it.
As far as affixing it, I can laser cut holes for screws and pre-drill them in the edge of the plywood to eliminate tear-out. That should actually allow me to make the front baffle removable as well for future tuning, to a degree anyway.
Even though it's thin, this stuff is really stiff. Certainly not as stiff as the plywood, though, which is why I asked if there's a problem using it.
As far as affixing it, I can laser cut holes for screws and pre-drill them in the edge of the plywood to eliminate tear-out. That should actually allow me to make the front baffle removable as well for future tuning, to a degree anyway.
I'm not sure how the surface of the acrylic will affect the sound. Also, if it isn't as stiff as plywood, it probably is less than ideal.
However, if you feel like trying it, you might find it's OK and you might be happy with it. Can you use two layers to give more rigidity?
I think you'll still need to recess it so the driver is flush with the baffle.
However, if you feel like trying it, you might find it's OK and you might be happy with it. Can you use two layers to give more rigidity?
I think you'll still need to recess it so the driver is flush with the baffle.
½” (12.7mm) with a 6mm rebate leaves little room for holding the driver. The acrylic would be good, particularily if you can stick it to the baffle with some sort of thickiss (1.7mm would be ideal) sticky both sides material in between. This would give you a pretty, constrained layer baffle.
dave
Ok, so it sounds like you guys are saying using just the acrylic as the front baffle is not a good idea. I don't get the significance of the driver being flush with the baffle surface, but I gather it's fairly critical? The acrylic isn't think enough for any sort of recessing. I'll probably just stick with the plywood baffle, especially since I think I may have figured out a relatively easy way to make a circle jig for my router table.
If the driver bezel is not flush the potential for waves exiting from the edge of the driver along the baffle will diffract at the bezel edge. And the older Alpairs have quite thick bezels.
I would definitely add the acrylic to the ½” plywood as a “decorative” addiiton to bring the bezel closer to flush. “decorative” on quotes because it also does double duty to bring the bezel closer to flush and will (if an appropriate coupling material/glue is used) a constrained laye ron th emost critical of th ebox panels. It also allows you to just cut circular holes in both the plywood (78mm) and the acrylic (100mm).
dave
I would definitely add the acrylic to the ½” plywood as a “decorative” addiiton to bring the bezel closer to flush. “decorative” on quotes because it also does double duty to bring the bezel closer to flush and will (if an appropriate coupling material/glue is used) a constrained laye ron th emost critical of th ebox panels. It also allows you to just cut circular holes in both the plywood (78mm) and the acrylic (100mm).
dave
Ok, I think I get it. The sound leaving the driver at a steep angle will encounter the edge of the driver and act almost like a lens, right? If it's flush, it only has one way to go. Am I getting the point?
I can add the acrylic layer, and I may well do that. I think it would look great. However, I'm not sure how I could affix it to the baffle without whatever I use as interface material showing through the semi-transparent acrylic and looking crummy. Do you know of a material that performs well and looks good?
By the way, I got the circle jig mostly worked out. I need to make a few tweaks for usability, but it routes accurate circles, so I'm happy. 😉
I can add the acrylic layer, and I may well do that. I think it would look great. However, I'm not sure how I could affix it to the baffle without whatever I use as interface material showing through the semi-transparent acrylic and looking crummy. Do you know of a material that performs well and looks good?
By the way, I got the circle jig mostly worked out. I need to make a few tweaks for usability, but it routes accurate circles, so I'm happy. 😉