Hi, I've found this kind of slot ports problematic, they tend to "leak" mids very loud, worst case even louder than the helmholz resonance itself. How is here, have you measured output of the port? I see you have this kind of port on both the sub and top box.
@tmuikku
so i actually plugged the ports with some wood and clamps, and the first thing i noticed was better bass integration (different group delay curve in the crossover region when going from ported to sealed) and more treble energy. it does sound "cleaner" for sure. I imagine that there was some midrange frequencies leaking out and arriving out of phase with the rest, reducing the perceived "treble". I'm definitely gonna make a new pair of front baffles with a sealed design as it sounds cleaner.
so i actually plugged the ports with some wood and clamps, and the first thing i noticed was better bass integration (different group delay curve in the crossover region when going from ported to sealed) and more treble energy. it does sound "cleaner" for sure. I imagine that there was some midrange frequencies leaking out and arriving out of phase with the rest, reducing the perceived "treble". I'm definitely gonna make a new pair of front baffles with a sealed design as it sounds cleaner.
Cool, if you have a microphone and means to hook it to a computer you could measure what happens when the port is open/closed. When blocking port many things change, and while I believe you hear more clarity it might not be a resonance but just better balance in frequency response or something, most likely combination of multiple things. Balance of highs and lows is very important, if too much bass the speaker sounds dull, if too much treble it sounds bright. Balance it just right to your ear, and keep resonances, peaks in the frequency response, at bay.
Resonances are annoying though, they are kind of hard to spot at first but one learns to listen them quite fast. They kind of mask and make feeling something is not right with the sound, they capture ones attention without revealing themselves. I've bumped on this with hobby recording and mixing, resonances from mics, drums, nose, things in the room, all kinds of extra sounds tend to do this. Find it, deal with it, and suddenly there is nice sound. This is what I try to achieve with speakers (system) as well, problem free sound. Some "problems" can be designed out, some will remain and need some attention/fixing. If port must stay, prepare a prototype to tweak its performance and accept the results achieved with the effort you are willing to invest 🙂
Have fun with the project! 🙂
Resonances are annoying though, they are kind of hard to spot at first but one learns to listen them quite fast. They kind of mask and make feeling something is not right with the sound, they capture ones attention without revealing themselves. I've bumped on this with hobby recording and mixing, resonances from mics, drums, nose, things in the room, all kinds of extra sounds tend to do this. Find it, deal with it, and suddenly there is nice sound. This is what I try to achieve with speakers (system) as well, problem free sound. Some "problems" can be designed out, some will remain and need some attention/fixing. If port must stay, prepare a prototype to tweak its performance and accept the results achieved with the effort you are willing to invest 🙂
Have fun with the project! 🙂
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Very nice work! In the true spirit of DIY
Btw, I would keep the plywood CNC'd horns, or maybe redo them if they're not perfect enough. Way cooler than 3D printing in plastic. IMHO only, of course
Btw, I would keep the plywood CNC'd horns, or maybe redo them if they're not perfect enough. Way cooler than 3D printing in plastic. IMHO only, of course
What if there's no CNC?
I have access to a band saw, which is fantastic! Except that it can't cut inside of a closed loop. Since the cuts are so thin and clean, I guess I could cut into a plywood ring and then glue the seam. That kind-of goes against my OCD, but I might end up doing that.
I have access to a band saw, which is fantastic! Except that it can't cut inside of a closed loop. Since the cuts are so thin and clean, I guess I could cut into a plywood ring and then glue the seam. That kind-of goes against my OCD, but I might end up doing that.
Thank you all for the kind words!
I heard somewhere on here they made a fusion360 plug in for creating horns so I’m gonna try and experiment with that and change the horn.
I do have a microphone and I’m gonna try and get some measurements and post them here.
I definitely might make them out of wood. The wood they’re made of now is a crappy Baltic birch ply from Home Depot and I can order the much nicer 13 layer ply that the rest of the cabinets are made of
I heard somewhere on here they made a fusion360 plug in for creating horns so I’m gonna try and experiment with that and change the horn.
I do have a microphone and I’m gonna try and get some measurements and post them here.
I definitely might make them out of wood. The wood they’re made of now is a crappy Baltic birch ply from Home Depot and I can order the much nicer 13 layer ply that the rest of the cabinets are made of
I don’t think a bandsaw would get anywhere close to an accurate horn flare unfortunately. A 3d printer is cheaper than a CNC and could give you great results
Tried that, and a scroll saw just won't do it. Mine can cut 6 mm plywood, even at a range of angles, so theoretically it could, with some sanding to smooth out the angles, but the pace is such that a stack of circles could take a week's work with 100% focus. And if your attention wanders for one second, so does the saw. Once you start "correcting", it digs in and pulls in the opposite direction, so it can't be rushed either. A handheld jigsaw could work, but then there's also a lot more dust and sanding.
@abstract
I think cutting a horn with any type of saw (scroll or band saw) isn’t a great idea. How would you know if what you’re cutting is accurate? Horn flare curves are very specific mathematically defined curves and I don’t think it’s possible to accurately cut one with a band or scroll saw,
I think cutting a horn with any type of saw (scroll or band saw) isn’t a great idea. How would you know if what you’re cutting is accurate? Horn flare curves are very specific mathematically defined curves and I don’t think it’s possible to accurately cut one with a band or scroll saw,
It could be a 2-step process: rough cutting, followed by sanding it down until it matches a guide for the flare rate. Ideally, a wood turning jig could work for a circular horn, but a biradial horn would be a bit harder to do.
For a ribbon tweeter there could be some repetitions of the same cut, but I'd have to think about the end pieces.
For a ribbon tweeter there could be some repetitions of the same cut, but I'd have to think about the end pieces.
I think it would be easier to just spend $600 on a good 3d printer and some filament, and print a horn. You’d save a lot of time as the building process is just waiting 12-18 hours for the printer to print the horn. I have a 3d printed prototype of my biradial horn on these speakers and it came out great. Took 8 hours but the final horn will have more density which dictates longer print time.
How closely the horn needs to adhere to the exact mathematical curve is very dependent on the frequenciees being reproduced. At LFs one can have numerically larger deviations than higher frequency devices but relative to the wavelength is just as accurate.
dave
@abstract you are right there, band saws are faster (given the probable blade selections). And it was a non-zero level of pain in terms of speed and taking the blade off and on to cut out 24 pie-wedges in some wagon-wheel like things recently. But it did have the advantage of being able to make the interior cuts. Once you get a feel for the appropriate cutting-speed I don't see much difference in the precision/attention aspects, free-handing or with a fence/jig. Edit: I basically stopped using a hand-held jig saw for anything but really rough cuts, could be I never got the knack.
Honestly, after thinking about it, if you accept piecing parts of each layer together, I think I would go with a router or table saw and a jig. I have seen jigs made that essentially turn table saws into lathes (although those are really easy to get wrong and make highly unsafe), and similar things to use routers (usually pretty safe). A pantograph like linkage (used big to small) would help get the jig's template accurate, or in some cases could directly define a parabolic arc.
@notnickparkin Sorry, I thought you were talking about a CNC cutting machine, which does have the advantage of consistent precision, unaffected by fatigue. I don't have one of those, but suspect it's like using a good jig - it almost feels like cheating. The 3-D printer outputs I have seen all had surfaces with 1/32-1/16" waves. So beyond the plug and chug aspect you describe, I don't know that I see much advantage. It's probably again then more about comfort/personal preference.
Honestly, after thinking about it, if you accept piecing parts of each layer together, I think I would go with a router or table saw and a jig. I have seen jigs made that essentially turn table saws into lathes (although those are really easy to get wrong and make highly unsafe), and similar things to use routers (usually pretty safe). A pantograph like linkage (used big to small) would help get the jig's template accurate, or in some cases could directly define a parabolic arc.
@notnickparkin Sorry, I thought you were talking about a CNC cutting machine, which does have the advantage of consistent precision, unaffected by fatigue. I don't have one of those, but suspect it's like using a good jig - it almost feels like cheating. The 3-D printer outputs I have seen all had surfaces with 1/32-1/16" waves. So beyond the plug and chug aspect you describe, I don't know that I see much advantage. It's probably again then more about comfort/personal preference.
Well, didn't mean to stop the conversation.
Anyway, here's what I was thinking about a non-CNC non-3D printer solution for a solid wooden horn using a router.
Wasn't sure if there was one profile or if the wide and narrow sides were the same profile, but it didn't appear so since they seem to meet in the corners. EDIT: If so, cutting the join would be a little trickier, probably adapt a technique used in building log homes.
At some point, it might be better to cut terraces (like the stepped horns in the bigger builds) and cover with bent (or home-made) ply sheets.
Anyway, here's what I was thinking about a non-CNC non-3D printer solution for a solid wooden horn using a router.
Wasn't sure if there was one profile or if the wide and narrow sides were the same profile, but it didn't appear so since they seem to meet in the corners. EDIT: If so, cutting the join would be a little trickier, probably adapt a technique used in building log homes.
At some point, it might be better to cut terraces (like the stepped horns in the bigger builds) and cover with bent (or home-made) ply sheets.
Hi everyone!
It’s been awhile! I just got my next batch of things in from Amazon. I got black aluminum potentiometer knobs and a much larger black knob for the main volume control. I also spent extra buck and got a nice programmable fan controller with two noctua redux 120mm fans (super quiet). This will ensure I have good cooling for the amps. It’s basically a nice small little unit that I will put on the back of the amplifier chassis. I also got a panel mount USB-C. This will allow me to plug in the programming cable via the front baffle for easy programming.
I was going to start cutting today but the wood company I ordered from messed up my order and instead of sending me eight 15” x 30” panels they sent me two 13” x 13” panels. They said I could keep the stuff they sent me and they’re sending my correct order soon so it should be here by the end of next week. Once I get the lumber, I will be able to cut a new amp chassis and make new front baffles for the main speakers. I’m starting to get this project wrapped up and I can’t wait to see how good it looks when I’m done!
I might also have enough lumber over to cut some Baltic birch stands for the main speakers.
It’s been awhile! I just got my next batch of things in from Amazon. I got black aluminum potentiometer knobs and a much larger black knob for the main volume control. I also spent extra buck and got a nice programmable fan controller with two noctua redux 120mm fans (super quiet). This will ensure I have good cooling for the amps. It’s basically a nice small little unit that I will put on the back of the amplifier chassis. I also got a panel mount USB-C. This will allow me to plug in the programming cable via the front baffle for easy programming.
I was going to start cutting today but the wood company I ordered from messed up my order and instead of sending me eight 15” x 30” panels they sent me two 13” x 13” panels. They said I could keep the stuff they sent me and they’re sending my correct order soon so it should be here by the end of next week. Once I get the lumber, I will be able to cut a new amp chassis and make new front baffles for the main speakers. I’m starting to get this project wrapped up and I can’t wait to see how good it looks when I’m done!
I might also have enough lumber over to cut some Baltic birch stands for the main speakers.
Hi everyone! Its been awhile! I finally completed the subwoofer front baffle, most of the amplifier chassis, more advanced DSP, and more!
First off, I completed the sub front baffle. It took 50 minutes to carve and looks great!
I am also 90% finished with the amp chassis. I have binding posts, everything is wired up, I have a front panel with a volume knob, lights, and a programming usb-c input for the boards. I have a fused power input, and a fan controller with temperature sensor that automatically controls the fan. The front baffle for the amp hasn't been glued in place and I may design a simple mechanism that holds the front baffle in with pins going through the sides so I can easily remove them and remove the front panel for easy access/repairs. I have two power supplies for the amps, and one 12v power supply for the fan controller.
all the front knobs are programmed and work great! one volume knob, one subwoofer volume knob, subwoofer crossover knob, tweeter level knob, and a woofer/mid level knob. Im gonna experiment with other dsp functions and see what cool stuff I can program the knobs to do.
all that's left to do is 3d print the horns and make new front baffles for the main speakers to make them sealed. im working on a model of the horn now and am trying to make the throat smaller for a higher high frequency cutoff.
First off, I completed the sub front baffle. It took 50 minutes to carve and looks great!
I am also 90% finished with the amp chassis. I have binding posts, everything is wired up, I have a front panel with a volume knob, lights, and a programming usb-c input for the boards. I have a fused power input, and a fan controller with temperature sensor that automatically controls the fan. The front baffle for the amp hasn't been glued in place and I may design a simple mechanism that holds the front baffle in with pins going through the sides so I can easily remove them and remove the front panel for easy access/repairs. I have two power supplies for the amps, and one 12v power supply for the fan controller.
all the front knobs are programmed and work great! one volume knob, one subwoofer volume knob, subwoofer crossover knob, tweeter level knob, and a woofer/mid level knob. Im gonna experiment with other dsp functions and see what cool stuff I can program the knobs to do.
all that's left to do is 3d print the horns and make new front baffles for the main speakers to make them sealed. im working on a model of the horn now and am trying to make the throat smaller for a higher high frequency cutoff.