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al_bundy
Weaksauce
- Joined
- Aug 3, 2023
- Messages
- 81
Translatet by chatgpt:
Hi,
I don’t even know where to start. There’s so much to tell. The 6.5″ subwoofer turned out a bit too big for the spot and lights up like a Christmas tree. So I decided to build a cheap, somewhat small subwoofer. Although “cheap” is always relative... Over the past few months, I’ve been ordering drivers from AliExpress for around €20–30 and am currently going the “budget route.” Whether it will pay off remains to be seen. I’ve never had any issues with Chinese amps before, so I ordered a 2.1 active module from AliExpress for the first time — cost me €61.39.
It’s rated 200 W, 100 W, heavy subwoofer, digital power amplifier board, 5.1 and 7.1 active amplifier board, pure bass 1CH, 4 Ohm, 8 Ohm.
Apparently, it doesn’t have a proper name. I had to add a green-yellow (ground) wire myself. If you constantly drive it at 100 W, for example with a frequency generator, it would probably get fried. But whatever — we probably won’t even hit 100 W peak. I’ve used smaller modules twice so far and they ran quite well with 50 W on 5″ and 6″ subwoofers. So this 100 W module should work just fine with the driver. Let’s hope so, lol.
For the subwoofer driver, I’m using a cheap BPA SW8.01. I’ve been completely happy with the SW5.01 and SW6.01 I used multiple times before. Now it’s time for the SW8.01. Unfortunately, there’s some bad news at BPA Acoustics — it seems the company is shutting down. Getting replacement drivers will probably be quite difficult. But it’s okay. So far, I haven’t damaged any drivers, and in the worst case, I’ll just put in a Peerless or something similar. The SW8.01 cost me about €50, so no big deal.
The enclosure is made from 18 mm MDF, with the front double-layered for design reasons — no other way around it. Behind the front panel, where the subwoofer is mounted, I routed a ring. That’s still pretty cheap — maybe around €20 worth of MDF. I also added some bracing, not so much for mechanical stress from pulses, but to ensure the thing glues together better and more reliably, which is a big point. You don’t want to do too much sanding. Also, after routing, the side panels warped — both of them actually.
I’d estimate up to 5 mm of warping. That’s totally normal for real wood. So I had to glue in a cross brace to provide surface area for stronger adhesion. Hopefully, the walnut won’t crack over the years from the stress… That’s why larger and especially thicker real wood parts are generally discouraged. But I’m just going for it — it’s always worked out so far… Basically, it’s not a question if future projects will go well, but when it won’t anymore…
The side panels are made from 36 mm thick walnut. That size is nearly impossible to get, and affordable? Not really. About €180 per side panel. So the wood alone costs around €380, while hardware is only about €180. You can hardly call that cheap anymore… Luckily, I found a sponsor, Woodseller, who provided me with the two panels. Thanks for that! Check them out, maybe there’s something for you too. Great contact with the guy and a huge selection.
https://www.woodsellers.com/produkte
I treated the side panels with shellac polish and then applied HAS Zweihorn high-gloss polish with anti-haze properties for a better finish. However, I still need to go over them again.
https://www.zweihorn.com/de/produkte/spezialprodukte/hochglanz-antischleier.html
The process is a whole different ballgame compared to applying three coats of hard wax oil. You have to do a lot more sanding with K600, and then you get busy filling the pores. I was a bit lazy and used more pumice powder for filling than recommended, and with that, I got away with just three rounds of filling. I’ll keep doing it that way. Normally, that would be a no-go for walnut with its relatively large pores. Six polishing rounds were needed, which is basically standard for a high-gloss finish.
In your head, you think it’s a lot of work. In practice, it’s okay since you can only work about half an hour per day on each panel. After every filling or polishing step, you have to wait a day. When you think you’re done, you wait another week because the oil needs to fully pull out. Then you polish on one or two more coats with high-gloss polishing compound. The waiting between steps is much worse for me than the hour of polishing and filling per day. I don’t really have the patience for this kind of thing because I want to finish projects quickly in my head. But it was bearable since you can always squeeze in that hour here and there. It’s also a bit hypnotic, which for me is a kind of meditation, lol. Especially since I’m pretty stress-sensitive.
The shellac polish comes as a set from Antik-greef.de, who also has their own YouTube channel and updates over the years, so you get comprehensive info on how shellac polishing works.
View: https://www.youtube.com/watch?v=ftH7Gz8Ne4o
The large set costs just under €60 and lasts quite a while. I used about 100 ml for the filler and around 200 ml of polish for the two parts. The containers come in 1000 ml and 500 ml sizes. For complete beginners who have no clue, this is great. After that, you can reorder whatever you need from anywhere since you have a rough idea of what’s required. However, I would always buy the shellac flakes, polish, and filler from there if you’re inexperienced. That way, you know how it works and what you have. If you know what you’re doing, you can mix the stuff yourself.
You can buy high-gloss polish cheaper directly from the manufacturer, and polishing oil is no rocket science and can be ordered cheaply on eBay. Consumables like sanding fleece, nitrile gloves, and sandpaper you can get at your local hardware store. What would have improved the set is a microfiber cloth plus balsam turpentine oil so you can remove the oil from the part before polishing to a high gloss. Optionally, the set would also benefit from including a sheepskin glove to work with the high-gloss polish. A microfiber cloth or soft cotton cloth works too, though. But let’s not be picky. You can buy these yourself somewhere else. This was my first attempt. For smaller, thinner real wood parts that are inexpensive, next time I’ll try applying the high-gloss polish with a cordless drill and polishing pad. For these parts, I used a synthetic glove meant for car polishing.
Well, as it stands now, I still need to polish the back sides of the parts, which I’ll do this weekend. That’s it. But it will probably take another 1–2 weeks. Better to wait a few days longer than too little, since the finish first needs to cure, and right now I still have a lot of coding to do for the water coolers (Asus Aorus X870I Pro Ice, Asus ROG Zenith 2 Alpha Extreme, Inno3D RTX 4060 Ti Twin X2 OC, Inno3D RTX 4070 Ti Super, Matrox M9188, MSI B450 Gaming Pro Carbon Max Wifi, MSI RTX 3070 Ti Ventus, Palit RTX 5090, XFX Swift Radeon RX 9070 XT). For this setup, I ordered a felt mat to protect the nice finish. On top of that goes regular baking paper.
Next up is black Nappa leather. Luckily, I still had three cowhides lying around, and about half a hide has now been used. One cowhide costs a good €100+. Fortunately, a few tanners supported me on this project. For gluing the leather this time, I used Primefix industrial spray adhesive, which holds much better than the spray adhesive I used before. It will probably hold faux leather well too. Really good stuff.
https://www.primefix.de/produkte/spruehkleber
For such cheap hardware, I wouldn’t be willing to invest €360 in wood and €80 in leather. The size isn’t that small either — a 25-liter net enclosure with external dimensions of 370 x 353 x 382 mm. According to WinISD, this achieves 36 Hz at -3 dB. But not in a closed box. A closed box would have reached 36 Hz only at -9 dB, which is unsatisfactory. Even 36 Hz isn’t ultra-deep bass, but I’m not 20 anymore either. This is currently right in my target zone.
This can only be achieved with two passive membranes from SB Acoustics, type SP20 PFCR-00, at €30 each. No additional weights will be added, as they would only negatively affect the frequency response in this case. The driver and passive membranes fit together perfectly — like hand in glove.
https://sbacoustics.com/product/6-sb20pfcr-00-paper/
The enclosure will later be dampened with two Sonofil bags. Light to medium damping, which improves the sound a bit, even though the material isn’t optimal, as Walwal demonstrated in 2015 on the Visaton forum. And yes, it’s acoustically noticeable. But with DSP, it doesn’t bother me, and everyone has their own room modes.
Fooling around with glass/rock wool and acoustic foam isn’t worth the effort for this hardware. Acoustic foam would still be acceptable, though again a financial factor. As for wool, I’d have to research first. That stuff generally releases dust particles that could get into the driver’s coils, which I definitely want to avoid. Sonofil is solid, and for anyone not playing in the Champions League, it’s perfectly fine. It has always been enough for me so far. I like to buy it from Intertechnik.
https://www.intertechnik.de/shop/zu...sonofil-weiss-1-beutel,583193,de,10209,979148
I’d really like to be done by now, but we still need to be patient a bit longer. In 2–3 weeks there might be the first soundcheck. Originally, I planned to install some RGB lighting, but temporarily I wasn’t mentally sharp enough to design it properly and ended up milling away more than necessary. So I scrapped that idea and am now just gluing it together as is. I even bought expensive 2K epoxy with extreme adhesive strength especially for this. That will probably be used some other time. I also have 5 China-made subs and 5 China-made fullrange drivers for Bluetooth speakers lying around waiting for a housing. So there will definitely be more Bluetooth speakers in the future. Of course, with proper finishes like high-gloss lacquer or shellac polish and leather, or sometimes even a jute sack finish like in the 1930s.
If you don’t want a bass reflex, passive membranes are a good alternative—and the best part is you avoid port noise that can sometimes occur. Plus, you save the effort of designing and building a port. Simply gluing a tweeter tube in there looks terrible. Many projects don’t have optimal ready-made ports, so you have to design and build them yourself (I’m reminded of the 6.5" bandpass project where I milled my own bass reflex tubes). For a “small” budget, this will be a solid subwoofer. Of course, not everyone needs to use 36mm walnut and slaughter a cow for the finish. You can get a solid, affordable finish with Warnex textured paint as well. When I compare the SW 6.01 to various Canton subs up to €300, the SW 6.01 outperforms those ready-made subs easily. The SW 8.01 will surely raise the bar even higher, and with a cheap finish you won’t spend €250. So yes, building it yourself is still financially worth it—even with a branded amp module like the Mivoc AM80 (80W @ 4 Ohm) that’s driven my 150W Wavecor for years, which actually wants 150W.
Visually, this is one of the nicest subs I’ve ever built so far. Simple yet stylish in a timeless design. I’m glad I solved the biggest challenge fairly well—the shellac polish. The first time, you’re not confident and worry about messing it up. I can’t afford to spend €180 on a side panel. I’m too poor for that. Quitting the project is out of the question…
The finish was a huge topic. I tried many lacquers (7 different ones), polishes, and abrasives. Le Tonkinois passed the practical test, as did the shellac polish. Weeks of experience gathering. Eventually, there will surely be a project with Le Tonkinois products too, which visually won’t make a difference but practically will. Shellac lasts 100 years. A “synthetic” lacquer maybe 20–30 years. But whatever. In 30 years, I might be dead anyway… And the process is fundamentally different.
Attached are the pictures, although there’s not much to see of the process itself this time. I haven’t had much time in the last 8 months. The MDF parts were milled 6 months ago… Don’t ask about milling time. The parts were all milled completely in 2D, not 2.5D. One side panel took about 2 days on the milling machine due to inefficient programming. For 2.5D, I would have needed special tools that I didn’t have, so the structure was milled as a pocket in 50µ steps. It doesn’t bother me, nor the machine. So all good. Afterwards, sanded and shellac applied.
Hi,
I don’t even know where to start. There’s so much to tell. The 6.5″ subwoofer turned out a bit too big for the spot and lights up like a Christmas tree. So I decided to build a cheap, somewhat small subwoofer. Although “cheap” is always relative... Over the past few months, I’ve been ordering drivers from AliExpress for around €20–30 and am currently going the “budget route.” Whether it will pay off remains to be seen. I’ve never had any issues with Chinese amps before, so I ordered a 2.1 active module from AliExpress for the first time — cost me €61.39.
It’s rated 200 W, 100 W, heavy subwoofer, digital power amplifier board, 5.1 and 7.1 active amplifier board, pure bass 1CH, 4 Ohm, 8 Ohm.
Apparently, it doesn’t have a proper name. I had to add a green-yellow (ground) wire myself. If you constantly drive it at 100 W, for example with a frequency generator, it would probably get fried. But whatever — we probably won’t even hit 100 W peak. I’ve used smaller modules twice so far and they ran quite well with 50 W on 5″ and 6″ subwoofers. So this 100 W module should work just fine with the driver. Let’s hope so, lol.
For the subwoofer driver, I’m using a cheap BPA SW8.01. I’ve been completely happy with the SW5.01 and SW6.01 I used multiple times before. Now it’s time for the SW8.01. Unfortunately, there’s some bad news at BPA Acoustics — it seems the company is shutting down. Getting replacement drivers will probably be quite difficult. But it’s okay. So far, I haven’t damaged any drivers, and in the worst case, I’ll just put in a Peerless or something similar. The SW8.01 cost me about €50, so no big deal.
The enclosure is made from 18 mm MDF, with the front double-layered for design reasons — no other way around it. Behind the front panel, where the subwoofer is mounted, I routed a ring. That’s still pretty cheap — maybe around €20 worth of MDF. I also added some bracing, not so much for mechanical stress from pulses, but to ensure the thing glues together better and more reliably, which is a big point. You don’t want to do too much sanding. Also, after routing, the side panels warped — both of them actually.
I’d estimate up to 5 mm of warping. That’s totally normal for real wood. So I had to glue in a cross brace to provide surface area for stronger adhesion. Hopefully, the walnut won’t crack over the years from the stress… That’s why larger and especially thicker real wood parts are generally discouraged. But I’m just going for it — it’s always worked out so far… Basically, it’s not a question if future projects will go well, but when it won’t anymore…
The side panels are made from 36 mm thick walnut. That size is nearly impossible to get, and affordable? Not really. About €180 per side panel. So the wood alone costs around €380, while hardware is only about €180. You can hardly call that cheap anymore… Luckily, I found a sponsor, Woodseller, who provided me with the two panels. Thanks for that! Check them out, maybe there’s something for you too. Great contact with the guy and a huge selection.
https://www.woodsellers.com/produkte
I treated the side panels with shellac polish and then applied HAS Zweihorn high-gloss polish with anti-haze properties for a better finish. However, I still need to go over them again.
https://www.zweihorn.com/de/produkte/spezialprodukte/hochglanz-antischleier.html
The process is a whole different ballgame compared to applying three coats of hard wax oil. You have to do a lot more sanding with K600, and then you get busy filling the pores. I was a bit lazy and used more pumice powder for filling than recommended, and with that, I got away with just three rounds of filling. I’ll keep doing it that way. Normally, that would be a no-go for walnut with its relatively large pores. Six polishing rounds were needed, which is basically standard for a high-gloss finish.
In your head, you think it’s a lot of work. In practice, it’s okay since you can only work about half an hour per day on each panel. After every filling or polishing step, you have to wait a day. When you think you’re done, you wait another week because the oil needs to fully pull out. Then you polish on one or two more coats with high-gloss polishing compound. The waiting between steps is much worse for me than the hour of polishing and filling per day. I don’t really have the patience for this kind of thing because I want to finish projects quickly in my head. But it was bearable since you can always squeeze in that hour here and there. It’s also a bit hypnotic, which for me is a kind of meditation, lol. Especially since I’m pretty stress-sensitive.
The shellac polish comes as a set from Antik-greef.de, who also has their own YouTube channel and updates over the years, so you get comprehensive info on how shellac polishing works.
View: https://www.youtube.com/watch?v=ftH7Gz8Ne4o
The large set costs just under €60 and lasts quite a while. I used about 100 ml for the filler and around 200 ml of polish for the two parts. The containers come in 1000 ml and 500 ml sizes. For complete beginners who have no clue, this is great. After that, you can reorder whatever you need from anywhere since you have a rough idea of what’s required. However, I would always buy the shellac flakes, polish, and filler from there if you’re inexperienced. That way, you know how it works and what you have. If you know what you’re doing, you can mix the stuff yourself.
You can buy high-gloss polish cheaper directly from the manufacturer, and polishing oil is no rocket science and can be ordered cheaply on eBay. Consumables like sanding fleece, nitrile gloves, and sandpaper you can get at your local hardware store. What would have improved the set is a microfiber cloth plus balsam turpentine oil so you can remove the oil from the part before polishing to a high gloss. Optionally, the set would also benefit from including a sheepskin glove to work with the high-gloss polish. A microfiber cloth or soft cotton cloth works too, though. But let’s not be picky. You can buy these yourself somewhere else. This was my first attempt. For smaller, thinner real wood parts that are inexpensive, next time I’ll try applying the high-gloss polish with a cordless drill and polishing pad. For these parts, I used a synthetic glove meant for car polishing.
Well, as it stands now, I still need to polish the back sides of the parts, which I’ll do this weekend. That’s it. But it will probably take another 1–2 weeks. Better to wait a few days longer than too little, since the finish first needs to cure, and right now I still have a lot of coding to do for the water coolers (Asus Aorus X870I Pro Ice, Asus ROG Zenith 2 Alpha Extreme, Inno3D RTX 4060 Ti Twin X2 OC, Inno3D RTX 4070 Ti Super, Matrox M9188, MSI B450 Gaming Pro Carbon Max Wifi, MSI RTX 3070 Ti Ventus, Palit RTX 5090, XFX Swift Radeon RX 9070 XT). For this setup, I ordered a felt mat to protect the nice finish. On top of that goes regular baking paper.
Next up is black Nappa leather. Luckily, I still had three cowhides lying around, and about half a hide has now been used. One cowhide costs a good €100+. Fortunately, a few tanners supported me on this project. For gluing the leather this time, I used Primefix industrial spray adhesive, which holds much better than the spray adhesive I used before. It will probably hold faux leather well too. Really good stuff.
https://www.primefix.de/produkte/spruehkleber
For such cheap hardware, I wouldn’t be willing to invest €360 in wood and €80 in leather. The size isn’t that small either — a 25-liter net enclosure with external dimensions of 370 x 353 x 382 mm. According to WinISD, this achieves 36 Hz at -3 dB. But not in a closed box. A closed box would have reached 36 Hz only at -9 dB, which is unsatisfactory. Even 36 Hz isn’t ultra-deep bass, but I’m not 20 anymore either. This is currently right in my target zone.
This can only be achieved with two passive membranes from SB Acoustics, type SP20 PFCR-00, at €30 each. No additional weights will be added, as they would only negatively affect the frequency response in this case. The driver and passive membranes fit together perfectly — like hand in glove.
https://sbacoustics.com/product/6-sb20pfcr-00-paper/
The enclosure will later be dampened with two Sonofil bags. Light to medium damping, which improves the sound a bit, even though the material isn’t optimal, as Walwal demonstrated in 2015 on the Visaton forum. And yes, it’s acoustically noticeable. But with DSP, it doesn’t bother me, and everyone has their own room modes.
Fooling around with glass/rock wool and acoustic foam isn’t worth the effort for this hardware. Acoustic foam would still be acceptable, though again a financial factor. As for wool, I’d have to research first. That stuff generally releases dust particles that could get into the driver’s coils, which I definitely want to avoid. Sonofil is solid, and for anyone not playing in the Champions League, it’s perfectly fine. It has always been enough for me so far. I like to buy it from Intertechnik.
https://www.intertechnik.de/shop/zu...sonofil-weiss-1-beutel,583193,de,10209,979148
I’d really like to be done by now, but we still need to be patient a bit longer. In 2–3 weeks there might be the first soundcheck. Originally, I planned to install some RGB lighting, but temporarily I wasn’t mentally sharp enough to design it properly and ended up milling away more than necessary. So I scrapped that idea and am now just gluing it together as is. I even bought expensive 2K epoxy with extreme adhesive strength especially for this. That will probably be used some other time. I also have 5 China-made subs and 5 China-made fullrange drivers for Bluetooth speakers lying around waiting for a housing. So there will definitely be more Bluetooth speakers in the future. Of course, with proper finishes like high-gloss lacquer or shellac polish and leather, or sometimes even a jute sack finish like in the 1930s.
If you don’t want a bass reflex, passive membranes are a good alternative—and the best part is you avoid port noise that can sometimes occur. Plus, you save the effort of designing and building a port. Simply gluing a tweeter tube in there looks terrible. Many projects don’t have optimal ready-made ports, so you have to design and build them yourself (I’m reminded of the 6.5" bandpass project where I milled my own bass reflex tubes). For a “small” budget, this will be a solid subwoofer. Of course, not everyone needs to use 36mm walnut and slaughter a cow for the finish. You can get a solid, affordable finish with Warnex textured paint as well. When I compare the SW 6.01 to various Canton subs up to €300, the SW 6.01 outperforms those ready-made subs easily. The SW 8.01 will surely raise the bar even higher, and with a cheap finish you won’t spend €250. So yes, building it yourself is still financially worth it—even with a branded amp module like the Mivoc AM80 (80W @ 4 Ohm) that’s driven my 150W Wavecor for years, which actually wants 150W.
Visually, this is one of the nicest subs I’ve ever built so far. Simple yet stylish in a timeless design. I’m glad I solved the biggest challenge fairly well—the shellac polish. The first time, you’re not confident and worry about messing it up. I can’t afford to spend €180 on a side panel. I’m too poor for that. Quitting the project is out of the question…
The finish was a huge topic. I tried many lacquers (7 different ones), polishes, and abrasives. Le Tonkinois passed the practical test, as did the shellac polish. Weeks of experience gathering. Eventually, there will surely be a project with Le Tonkinois products too, which visually won’t make a difference but practically will. Shellac lasts 100 years. A “synthetic” lacquer maybe 20–30 years. But whatever. In 30 years, I might be dead anyway… And the process is fundamentally different.
Attached are the pictures, although there’s not much to see of the process itself this time. I haven’t had much time in the last 8 months. The MDF parts were milled 6 months ago… Don’t ask about milling time. The parts were all milled completely in 2D, not 2.5D. One side panel took about 2 days on the milling machine due to inefficient programming. For 2.5D, I would have needed special tools that I didn’t have, so the structure was milled as a pocket in 50µ steps. It doesn’t bother me, nor the machine. So all good. Afterwards, sanded and shellac applied.
