Newbie DIY sub advice

[rojo]

I'll recalculate probably some time tomorrow. I'm on the road all day today.

 

[sleepyhead]

I'll recalculate probably some time tomorrow. I'm on the road all day today.

Absolutely no rush, rojo. I was in the home depot store buying some material to mount my screen and projector, so I took the opportunity to look for the concrete forming tube. I spent the past couple of days helping my buddy make the screen and projector. (He's 100 times better at this DIY stuff than me and he seems to enjoy making stuff.)

@lsiberian
Those Daytons look really good! Thanks for the suggestions! Would a Dayton be suitable for a sonotube design?

 

[rojo]

@sleepyhead Let's assume that's 300mm outer diameter for those concrete form tubes, and we'll estimate that the wall is 6mm thick. I'm just barely able to shoehorn a Peerless XLS 10" driver into one of those 300mm x 1m tubes. I know @lsiberian will be pleased with that driver, as it's the same driver as is used in the highly regarded BK Electronics XLS200.

The basket cutout is 240mm. The driver's outer mounting flange is 269.3mm. If the inner diameter of the enclosure is 288mm, that isn't going to give you enough space to mount binding posts underneath. You'll probably have to get a little creative for the binding posts -- maybe mounting a binding post plate to one of the floor plate legs instead, or a single speakon terminal on the tube. And actually, given your likely choice of amp, a speakon terminal would probably be the best form of connection.

I had to tune it slightly above the driver's Fs to keep at least 10cm clearance between the vent and the driver. This model does not allow flaring the entry point of the vent. Flare the exit only -- otherwise either your vent will be too long or your tuning will be stretched higher than I've already stretched it. Also, you must surface mount the driver for the same reason. If you flush mount it, unless you use a thicker baffle, you won't have enough clearance between the driver magnet and the port.

Note: the warning from the following screenshot states that there's less than 2.5cm between the driver basket and the tube wall. 2.4cm ought to be close enough though. (288mm inner dia - 240mm cutout = 48mm / 2 = 24mm between basket and tube)

As before, the lighter green bold line is simulated with no EQ filters. The darker green line has the following filters applied:

Here's the predicted response at 300W:

Impedance:

Excursion at 300W:

Vent air velocity at 100W in meters / second:

I'm pleased with this design. It's actually got slightly better infrasonic extension than the RE Audio model, and in a smaller enclosure.

------

Or if you want to be completely lazy, you could just load one of the Peerless XLS10's into a prefab sealed truck box and plan to EQ the crap out of it with your miniDSP. This driver is critically damp with only 0.7 cubic feet / 19.8 liters of space in a sealed enclosure. (Sealed is 11dB weaker at 20Hz than vented, playing 93dB at 20Hz with 300W power, but it will actually be stronger than ported below 16Hz if such matters are important to you.)

 

[sleepyhead]

You, sir, are just a monster, like Sully from Monsters Inc. All this guidance and help (all the leg work here) is just phenomenal. If any of you come to Japan, I'll buy you a beer and show you around any places I know!

I'm sure EQ'ing the crap out of the subwoofer is not a great idea. What I'm thinking is that to adjust the signal that much means a loss of strength. I'm sure boosting the signal in the weaker areas will force the subwoofer to do something it's not happy doing, right?

I've not experienced anything below 16Hz, so what do you get with that? is it really worth the effort? I always see adverts and posts about subwoofers hitting sub 20Hz. Is there a lot of content in movies or is it just specialist LFE tracks? If it's pretty specialist, then I can easily forgo that.

There's some vocabulary that you used that I'm struggling to understand at the moment (plus I'm at work today, so using work time for forum use is pretty much a no-no! haha).

This part "you must surface mount the driver ", does that mean the driver sits on top of the 3/4 inch baffle and then the baffle attaches to the tube?

Also, if the length is an issue, could I just get the 2m length and cut it to size? It looks like reinforced cardboard inside, so I'm sure I can use the equipment at home depot to back the correct length cut or does that ad a variable that could throw a spanner in the works?

P.S. I found the Sonotube software you used, so I'm going to try using it myself!

 

[rojo]

You, sir, are just a monster, like Sully from Monsters Inc. All this guidance and help (all the leg work here) is just phenomenal. If any of you come to Japan, I'll buy you a beer and show you around any places I know

Kirin Ichiban is pretty tasty. That's the only Japanese beer I know though.

I'm sure EQ'ing the crap out of the subwoofer is not a great idea. What I'm thinking is that to adjust the signal that much means a loss of strength. I'm sure boosting the signal in the weaker areas will force the subwoofer to do something it's not happy doing, right

Well, if you get the Behringer iNuke, you'll have plenty of power to drive two of these subs to their excursion limits I'm sure. It's just that, as I mentioned before, sealed enclosures are less efficient than vented. You got WinISD to play with, right? Try modeling the XLS10 both in a sealed enclosure and in a vented, and you can see the difference. Sealed has a more gradual low-end rolloff, but the rolloff starts at a much higher frequency. You'll have to pick a frequency to flatten to as your target. So if you flatten down to, say, 25 Hz, your sub will have a few dB more overall output than if you flatten down to 20Hz. You won't be able to boost 20Hz higher than 93dB in a sealed box. That's the point at which the driver reaches its excursion limit and starts to bottom out. But, with room gain and corner loading, real-world response usually results in a more shallow slope than the model predicts.

I've not experienced anything below 16Hz, so what do you get with that? is it really worth the effort? I always see adverts and posts about subwoofers hitting sub 20Hz. Is there a lot of content in movies or is it just specialist LFE tracks? If it's pretty specialist, then I can easily forgo that.

Advertisements for subs hitting below 20Hz don't really give you enough of a picture to understand how the sub will sound. 20Hz at what SPL? At what distance? At what level of harmonic distortion? CEA-2010 measurements are a pretty good way to answer these questions, but few sub makers publish this data or want it published. Hard data doesn't often reinforce optimistic marketing. And even then, some CEA-2010 figures are published with peak values at 1m, while others have RMS values at 2m.

I'm kind of an oddball. Most people run either vented subs or sealed, but I run one of each. My vented sub shoulders most of the burden from 20 to 40Hz or so, and my sealed handles infrasonics. Both together handle the upper range. My miniDSP filters look like unwound dental floss, but it sounds great. There are a few movies and songs that have low frequency effects down to 16Hz or lower, but you can easily live without that sort of extension.

There's some vocabulary that you used that I'm struggling to understand at the moment (plus I'm at work today, so using work time for forum use is pretty much a no-no! haha).

This part "you must surface mount the driver ", does that mean the driver sits on top of the 3/4 inch baffle and then the baffle attaches to the tube

Well, it just means the driver isn't countersunk into the baffle. The opposite is to flush mount the driver, so the first layer of the baffle is cut to the outer diameter of the driver's mounting ring while the second is cut to the basket. If by "sits on top" you mean it looks like this mock-up with the driver mounted to the surface of the baffle, then yes.

Also, if the length is an issue, could I just get the 2m length and cut it to size? It looks like reinforced cardboard inside, so I'm sure I can use the equipment at home depot to back the correct length cut or does that ad a variable that could throw a spanner in the works?

P.S. I found the Sonotube software you used, so I'm going to try using it myself!

That driver really wouldn't benefit from a larger enclosure. Besides, concrete form tube is very difficult to cut straight. The compromise on the vent length only resulted in about a quarter to a half dB less output at the corner frequency in my models. Just stick with the 1m length tube.

One possible concern with the Behringer iNuke and the suggested Crown amp: they're professional amps meant for lower impedance preamp signals I think. If you get this gear and it has less output than you expected, you might need some sort of preamp signal booster or unbalanced <-> balanced line level converter. Cross that bridge when you get to it, though. More likely than not, it'll sound great without having to resort to additional gadgets.

 

[sleepyhead]

Sorry, I've been a little busy lately. Just set up my projector and screen but the alignment is just out by an inch (which is driving me crazy).

I've tried modelling the Peerless driver in winISD, but I must have done something wrong as in sealed the roll off starts from 70or so Hertz. No matter what box parameters I set, the roll off starts in that region. I also seem to be missing something when using sonotube. I'll try again another day.

I think your solution with the sonotube and Peerless driver is the best and I'll get to work on it as soon as cash is available. Two of those should fill out the bottom end nicely. I don't have a way to cut perfect circles, so I'm thinking of a handheld jigsaw and a lot of sanding!

I noticed you used the 10cm diameter PVC for the port. Would using the 15cm be better? Or how about 2 7.5 cm ports? You mentioned how there needs to be a 10cm clearance between vent and driver, so could we get away with different port diameters to reduce the port length?

P.S. Kirin is good, but I'm a Suntory Rich Malt guy. (But nothing beats a good chilled glass of Hoegaarden).

P.P.S. I remeasured the smallest dimension and it's actually 52cm! This is from the floor to the bottom of the screen, but I can put the Subwoofers in the corner so there is about 45 cm width availability.

 

[rojo]

Sorry, I've been a little busy lately. Just set up my projector and screen but the alignment is just out by an inch (which is driving me crazy).

I've tried modelling the Peerless driver in winISD, but I must have done something wrong as in sealed the roll off starts from 70or so Hertz. No matter what box parameters I set, the roll off starts in that region. I also seem to be missing something when using sonotube. I'll try again another day.

Nope. You're probably not doing it wrong. This is the difference between sealed and ported for the XLS10 at 200W (sealed in a 19.9L box, Q of 0.5; and vented in a 52L box tuned to 22.5Hz like the tube).

This difference is a pretty typical representation for sealed vs. ported for any driver in proper enclosures.

I think your solution with the sonotube and Peerless driver is the best and I'll get to work on it as soon as cash is available. Two of those should fill out the bottom end nicely. I don't have a way to cut perfect circles, so I'm thinking of a handheld jigsaw and a lot of sanding!

Just as long as you get the end caps good and sealed into the concrete form tube, it doesn't have to be pretty. Gorilla glue can expand and fill the gaps if you don't get your edges perfectly round. But be conservative with your use of it, as it will seep out as it expands. Does Japan have Gorilla glue?

If using a jigsaw, you'll probably be better off with a hardwood ply, like birch. MDF will cause you to go through more blades and swearing I think. Besides, with ply, you can stain it and make it pretty.

I noticed you used the 10cm diameter PVC for the port. Would using the 15cm be better? Or how about 2 7.5 cm ports? You mentioned how there needs to be a 10cm clearance between vent and driver, so could we get away with different port diameters to reduce the port length?

Bigger tube requires longer length to keep the same tuning. Smaller tube increases vent air speed and turbulence (chuffing). Multiple smaller tubes still require longer length. Stop screwing with my design. It's already where it needs to be!

P.S. Kirin is good, but I'm a Suntory Rich Malt guy. (But nothing beats a good chilled glass of Hoegaarden).

I hope Suntory Rich Malt isn't like Colt 45. Hoegaarden is tasty! My current favorite is Magic Hat #9 not-quite-pale-ale.

P.P.S. I remeasured the smallest dimension and it's actually 52cm! This is from the floor to the bottom of the screen, but I can put the Subwoofers in the corner so there is about 45 cm width availability.

So you can have a box that's 20" tall and your width and depth aren't limited? That puts the 15" options back into play. Would you rather build a box or stick with the tube idea? FWIW, Sonosub estimates the completed tube to weigh 17kg. An 8 cu. ft. box with bracing will weigh many times that much and require many more hours of cutting and gluing; but you will get a few more dB of output, as well as a couple Hz deeper infrasonic extension.

---------

Be thinking about how you're going to connect your amp to your subs. As I mentioned before, if you go with the Behringer amp, a Neutrik Speakon cable and terminal would probably be best. See if you can find a source for something like this Speakon connector terminal to put into your build(s). (I found one on Amazon Japan, but $30 seems awfully steep for a $2 piece of cheap plastic crap.) Edit: Direct from China!

This cable or this longer one or similar would then be used to connect your sub(s) to your amp.

 

[lsiberian]

The Peerless is definitely a great option.

FWIW for me building a prism enclosure is much easier than a sonosub. I actually tried a sonosub once and it was disastrous for me trying to cut it to length.

Mind you I have all the tools to properly build a prism enclosure. Bar clamps, corner clamps, table saw, plunge router with high quality bits and blades.

 

[rojo]

The Peerless is definitely a great option.

FWIW for me building a prism enclosure is much easier than a sonosub. I actually tried a sonosub once and it was disastrous for me trying to cut it to length.

Mind you I have all the tools to properly build a prism enclosure. Bar clamps, corner clamps, table saw, plunge router with high quality bits and blades.

That's the beauty though. The tube is already the correct length without needing cut!

 

[sleepyhead]

Nope. You're probably not doing it wrong. This is the difference between sealed and ported for the XLS10 at 200W (sealed in a 19.9L box, Q of 0.5; and vented in a 52L box tuned to 22.5Hz like the tube).

This difference is a pretty typical representation for sealed vs. ported for any driver in proper enclosures.

Ahh yeah! That was the kind of shape I was getting on winISD for sealed. Good to know I am not using the program incorrectly

Just as long as you get the end caps good and sealed into the concrete form tube, it doesn't have to be pretty. Gorilla glue can expand and fill the gaps if you don't get your edges perfectly round. But be conservative with your use of it, as it will seep out as it expands. Does Japan have Gorilla glue?

If using a jigsaw, you'll probably be better off with a hardwood ply, like birch. MDF will cause you to go through more blades and swearing I think. Besides, with ply, you can stain it and make it pretty.

Pretty sure Japan has Gorilla Glue or the equivalent. I'm a little busy this weekend (well my weekend, which is Thursdays and Fridays) so I won't be able to check for a couple of weeks. Same with the hardwood ply.

Bigger tube requires longer length to keep the same tuning. Smaller tube increases vent air speed and turbulence (chuffing). Multiple smaller tubes still require longer length. Stop screwing with my design. It's already where it needs to be!

Heh! Alright. I got the message.

I hope Suntory Rich Malt isn't like Colt 45. Hoegaarden is tasty! My current favorite is Magic Hat #9 not-quite-pale-ale.

Oh! I don't know those drinks. Wonder if I can find it at Yamaya (the international liquor store here)

So you can have a box that's 20" tall and your width and depth aren't limited? That puts the 15" options back into play. Would you rather build a box or stick with the tube idea? FWIW, Sonosub estimates the completed tube to weigh 17kg. An 8 cu. ft. box with bracing will weigh many times that much and require many more hours of cutting and gluing; but you will get a few more dB of output, as well as a couple Hz deeper infrasonic extension.

Weighing up the different options, I feel the Sonosub idea is the simplest concept and execution for a beginner like me. Having a bigger box that could be more complex to build could be a project further down the line. Plus space isn't a big issue for me as I live by myself but could pose a problem if I have more than 3 people over and there are two huge subwoofer boxes in the way. The Sonosub fills the need of being light enough, easy enough to move and locate and ease of build with the tradeoff being infrasonic range. At the moment, I feel like that is a worthwhile tradeoff with me, but that could change in the future...

Be thinking about how you're going to connect your amp to your subs. As I mentioned before, if you go with the Behringer amp, a Neutrik Speakon cable and terminal would probably be best. See if you can find a source for something like this Speakon connector terminal to put into your build(s). (I found one on Amazon Japan, but $30 seems awfully steep for a $2 piece of cheap plastic crap.) Edit: Direct from China!

This cable or this longer one or similar would then be used to connect your sub(s) to your amp.

!!! I spent the past week looking at twist lock speaker cables and wondered about the terminals on the sonosub. You seemed to have read my mind. I saw that I could get the RCA to TR / TRS cables (I got the vocabulary from the manual, so the name might be wrong, but that's the type of connector I need) to run from a miniDSP to an iNuke NU1000, but had an open question on the speaker cables. Thank you for answering that so quickly without me openly asking!


EDIT:
Shopping list.

• 30cm diameter Sonotube QTY:2
• PVC tube, 10cm x 100cm QTY:2
• Peerless XLS 830452 QTY:2
• Hardwood plywood (birch) 1.9cm thick
• Speakon connectors QTY:2
• Twist-lock speaker cable 10m or this 5m version QTY:2
• Behringer iNuke NU1000 or NU1000DSP (which should I get?) QTY:1
• RCA / TRS cable 1.5m QTY:1 pair
• miniDSP 2x4 or 2x4HD or 2x4 Balanced (again, which one should I get) QTY:1
• nuts / bolts / screws / glue?

This may sound dumb but how do I connect the connector to the driver? Also, do I cut a hole in the sonotube for the connector or should it be placed elsewhere?

 

[rojo]

Oh! I don't know those drinks. Wonder if I can find it at Yamaya (the international liquor store here)

Leinenkugel's Sunset Wheat is very nice as well. Not sure whether it's power of suggestion from the blue label, but it tastes like there's a hint of blueberry in it. It's a little girlie, but still very much worth a try if they don't have Magic Hat #9.

EDIT:
Shopping list.

• 30cm diameter Sonotube QTY:2
• PVC tube, 10cm x 100cm QTY:2
• Peerless XLS 830452 QTY:2
• Hardwood plywood (birch) 1.9cm thick
• Speakon connectors QTY:2
• Twist-lock speaker cable 10m or this 5m version QTY:2
• Behringer iNuke NU1000 or NU1000DSP (which should I get?) QTY:1
• RCA / TRS cable 1.5m QTY:1 pair
• miniDSP 2x4 or 2x4HD or 2x4 Balanced (again, which one should I get) QTY:1
• nuts / bolts / screws / glue?

This may sound dumb but how do I connect the connector to the driver? Also, do I cut a hole in the sonotube for the connector or should it be placed elsewhere?

Add speaker wire (just like a couple meters of 14 gauge or 2mm² stranded copper pair would be more than plenty) to run signal from the Speakon terminal to the driver. Look for female slide connectors (something like these) to make the connections; or you can solder the wire directly onto the tabs if you prefer. Your home improvement store probably has both the speaker wire and the female slide disconnects. If not, check a local car audio shop.

You should also get a wooden dowel or two to cut and use as feet and table top standoffs. For the diameter of the dowel, just use your best judgement. Remember that the diameter of the exposed portion of the bottom baffle needs to accommodate both the driver (about 270mm) and the dowel feet; and the whole thing needs to fit within 40 - 45cm per your intended placement restrictions.

And the feet and table top remind me, you might want to find a second type of wood glue for these pieces that doesn't expand the way Gorilla Glue does.

Re: Behringer iNuke, if you're planning to get a miniDSP you really won't need the iNuke DSP. You can save money and just get the basic NU1000.

Speaking of saving money, the Speakon terminal and cables you found on Amazon would be quite a bit cheaper from AliExpress. See the links at the bottom of post #47.

miniDSP, you'll be going from an AVR subwoofer out into the miniDSP I guess? Since that connection is unbalanced, you should strike the balanced version from your list. Likewise, since the subwoofer out isn't optical, there's no benefit to paying extra for the HD version. I'd just get the miniDSP 2x4. Can you order direct from minidsp.com? Seems to be quite a bit cheaper ordering direct. You'll also need a software plugin for it -- the 2-way Advanced; as well as a calibrated measurement microphone. Here's a tutorial to help you figure out how to make use of the microphone.

For the mounting location of the Speakon connector, tentatively plan to drill a hole in the wall of the sonotube. Once you get the thing built, you might find there is enough space on the baffle next to the driver. Just kind of hold it up in various locations and see where you like it best. But you might want to wrap your sonotube in vinyl or car audio box carpet or paint it or something before you screw the terminal down and seal it. So add clothes for your subs to the shopping list.

Re: thickness of the plywood, 3/4" ~= 1.9cm. If it's sold as 2cm, that isn't significant enough to affect the tuning of the sub in any audible way.

Hope I'm not forgetting anything. Stain and lacquer for finishing the wood?

 

[sleepyhead]

Well my cheap manual pull down projector screen just broke...Gonna send it back, so that ruined my day off yesterday (Friday). If I knew it was gonna do that then i would have gone to the DIY shop and got some of the stuff for the sonotube.

There is a car shop around the corner from where I live, so I might see if they can paint or lend me their equipment to paint the sonotube, but I got to work out how I can explain that in Japanese! I'll also ask if they can cut the wood for me too. I can easily spend time sanding stuff down to smooth it out or get the exact shape / dimensions.

I was thinking instead of dowels, I was going to get 4 rubber feet, 4 long bolts, 20-25mm spacers and wingnuts. Put the bolts through the feet, floor plate and end cap, hand tightened with a wingnut. I'll probably throw in some washers too, just for the hell of it!

Also, I just put links into Amazon more as a reminder for me of what I need to get. Considering the price of the Peerless driver went up on Amazon, I might get it from Bayside net as it's a good 6,000 yen cheaper there. The cables and connectors I might get it from aliexpress, but it depends on how shipping and price conversations works out.

The biggest question mark I have right now is finding out what Birch plywood is in Japanese, or at least the DIY name for it. There is "Japanese Cherry Birch" (ヨグソミネバリ) and "Japanese white birch" (白樺) in the dictionary I have, but I don't know if that is the same birch that is needed. I never knew there were so many types of birches!

Thanks for the advice on the iNuke and miniDSP. The idea is AVR -> miniDSP -> iNuke -> subwoofers. That mic guide is super handy! Thanks!

Pretty excited about making these! C'mon payday!

 

[rojo]

Well my cheap manual pull down projector screen just broke...Gonna send it back, so that ruined my day off yesterday (Friday). If I knew it was gonna do that then i would have gone to the DIY shop and got some of the stuff for the sonotube.

There is a car shop around the corner from where I live, so I might see if they can paint or lend me their equipment to paint the sonotube, but I got to work out how I can explain that in Japanese! I'll also ask if they can cut the wood for me too. I can easily spend time sanding stuff down to smooth it out or get the exact shape / dimensions.

I was thinking instead of dowels, I was going to get 4 rubber feet, 4 long bolts, 20-25mm spacers and wingnuts. Put the bolts through the feet, floor plate and end cap, hand tightened with a wingnut. I'll probably throw in some washers too, just for the hell of it!

Also, I just put links into Amazon more as a reminder for me of what I need to get. Considering the price of the Peerless driver went up on Amazon, I might get it from Bayside net as it's a good 6,000 yen cheaper there. The cables and connectors I might get it from aliexpress, but it depends on how shipping and price conversations works out.

The biggest question mark I have right now is finding out what Birch plywood is in Japanese, or at least the DIY name for it. There is "Japanese Cherry Birch" (ヨグソミネバリ) and "Japanese white birch" (白樺) in the dictionary I have, but I don't know if that is the same birch that is needed. I never knew there were so many types of birches!

Thanks for the advice on the iNuke and miniDSP. The idea is AVR -> miniDSP -> iNuke -> subwoofers. That mic guide is super handy! Thanks!

Pretty excited about making these! C'mon payday!

That sucks about your screen. I'm not familiar with any techniques on making your own reflective screen, so I'd probably be in the same situation as you. Wish I had some wisdom to offer here.

Regarding the feet, just make sure there's at least 8.5cm clearance between the bottom baffle and the floor plate. You can have more, but 8.5cm is the minimum. If you want your bottom base to be removable, then glue the dowel legs to the baffle, but use wood or drywall screws through the floor plate.

I don't guess the wood specifically has to be birch. What do they use for subflooring there? As long as it's not pine or some other sort of soft wood and not particle board, it's bound to be good for building sonosub baffles. Whatever you end up with, try to select a sheet without knots, or at least try to cut it so that the knots are either on the floor plate or the table top. Stained knots can add some nice visual character as long as you aren't trying to cut through them.

That's awesome that Baysidenet has the Peerless driver cheaper than Amazon. Edit: Oh cool! Found you some Gorilla Glue. Seems a little high, but at least we know it's available. For gluing seams where you don't want the glue to expand -- e.g. sandwiching the baffle halves, sealing the Speakon terminal, and gluing in the PVC vent, use something like Liquid Nails. And actually, if your baffles are cut with a router, perfectly round, and tight-fit into the tube, you can do the whole sub with Liquid Nails if you wish and forget the Gorilla Glue entirely. Edit 2: I'd thought about suggesting using spikes to couple the bottom baffle to the floor plate, but I've changed my mind. According to this article spikes focus energy rather than isolate it, so coupling the sub to the floor plate with spikes doesn't offer any advantage over permanently joining the sub to the floor plate with dowel legs or similar.

 

[sleepyhead]

That sucks about your screen. I'm not familiar with any techniques on making your own reflective screen, so I'd probably be in the same situation as you. Wish I had some wisdom to offer here.

It's what I get for buying a cheap 100" pull down screen. Seems the bearings and the locking mechanism are out of alignment or have seized. One or the other. Hope I can get a refund!

Regarding the feet, just make sure there's at least 8.5cm clearance between the bottom baffle and the floor plate. You can have more, but 8.5cm is the minimum. If you want your bottom base to be removable, then glue the dowel legs to the baffle, but use wood or drywall screws through the floor plate.

OK. Got it. My line of thinking was making the floor plate and bottom end cap wider than the tube, so the feet (the rubber feet will go under the floor place) and spacers are further away from the driver. Also, a wider base should mean it's more stable in an earthquake prone region!

I don't guess the wood specifically has to be birch. What do they use for subflooring there? As long as it's not pine or some other sort of soft wood and not particle board, it's bound to be good for building sonosub baffles. Whatever you end up with, try to select a sheet without knots, or at least try to cut it so that the knots are either on the floor plate or the table top. Stained knots can add some nice visual character as long as you aren't trying to cut through them.

I have no idea what they use for subflooring here, but I should be heading to the DIY shop on Thursday or Friday so I can find out then. I'll probably buy all the raw materials then as well. The more expensive stuff will have to wait for a couple more weeks. I've not done any woodworking before so staining could be an interesting experiment for me!

That's awesome that Baysidenet has the Peerless driver cheaper than Amazon. Edit: Oh cool! Found you some Gorilla Glue. Seems a little high, but at least we know it's available. For gluing seams where you don't want the glue to expand -- e.g. sandwiching the baffle halves, sealing the Speakon terminal, and gluing in the PVC vent, use something like Liquid Nails. And actually, if your baffles are cut with a router, perfectly round, and tight-fit into the tube, you can do the whole sub with Liquid Nails if you wish and forget the Gorilla Glue entirely. Edit 2: I'd thought about suggesting using spikes to couple the bottom baffle to the floor plate, but I've changed my mind. According to this article spikes focus energy rather than isolate it, so coupling the sub to the floor plate with spikes doesn't offer any advantage over permanently joining the sub to the floor plate with dowel legs or similar.

Ahh ok. I get it. I'm sure I saw liquid nails at the DIY store. How much would I need? 500ml? 1000ml? I'd hate to buy too much, but even worse if I don't buy enough!

Also, I remember you said to only flare one end due to the length of the port. Which end should be flared? The exit or entrance?

I also have a questions about the miniDSP. I was going through the ordering section and noticed I have to select the input jumper: should I get 0.9Vrms or 2Vrms? I believe the sub pre-out on the TX-SR343 is 1V.

EDIT: Since starting down this quest, I've found so many minor audio problems that I had never noticed before. I opened Pandoras box!

 

[rojo]

OK. Got it. My line of thinking was making the floor plate and bottom end cap wider than the tube, so the feet (the rubber feet will go under the floor place) and spacers are further away from the driver. Also, a wider base should mean it's more stable in an earthquake prone region!

Ah, forgot about earthquakes! You could use a vinyl strap to anchor the sub to the walls, or you could build it for horizontal placement. In any case, the center of gravity should be quite low with the driver acting as ballast, so I doubt it'll be easy to tip over.

I have no idea what they use for subflooring here, but I should be heading to the DIY shop on Thursday or Friday so I can find out then. I'll probably buy all the raw materials then as well. The more expensive stuff will have to wait for a couple more weeks. I've not done any woodworking before so staining could be an interesting experiment for me!

Staining is easy! Brush on some stain, let it dry, rub out pimples with fine steel wool, repeat until pretty. I've never lacquered though. Might want to watch a YouTube video or two.

Ahh ok. I get it. I'm sure I saw liquid nails at the DIY store. How much would I need? 500ml? 1000ml? I'd hate to buy too much, but even worse if I don't buy enough!

Might as well go for the 1000mL if you're building 2 subs.

Also, I remember you said to only flare one end due to the length of the port. Which end should be flared? The exit or entrance?

Flare the exit. You won't actually flare the PVC. Just round over the hole in the center of the top baffle as illustrated in Sonosub's illustrations.

I also have a questions about the miniDSP. I was going through the ordering section and noticed I have to select the input jumper: should I get 0.9Vrms or 2Vrms? I believe the sub pre-out on the TX-SR343 is 1V.

EDIT: Since starting down this quest, I've found so many minor audio problems that I had never noticed before. I opened Pandoras box!

Go with the 0.9Vrms RevA option.

One other thing, looks like the Speakon cables I linked from AliExpress sold out. Only vendor I see today is this one. Still quite a high percentage cheaper than Amazon's offerings, and with a braided cable jacket for cold Japan nights. Or you could get like 4 Speakon connector ends and build your own cables in any length you wish.

 

[sleepyhead]

Went to look for liquid nails and couldn't find it. I did find a load of other adhesives, ones specifically for wood. I also found silicon and acrylic sealants too. Gorilla glue is freaking expensive at like $40 for 115ml!

Thanks for the miniDSP advice.

Also I decided to measure the concrete form tube and PVC pipe. The concrete form tube is 30cm ID and 30.8cm OD. The PVC tube is 10.5cm ID and 11.3cm OD. Is any of this an issue?

 

[KEW]

I'm loving this thread!
Given the catalyst of Sleepyhead's enthusiasm, this represents the forum at its best!!!

Don't get hung up on brand names. You'll end up ordering common products through specialty import channels resulting in a small container of Gorilla Glue for $40!
I think you can reasonably substitute any "polyurethane glue" instead of "Gorilla Glue". Apparently GG is a brand not readily available there. Polyurethane glue was nothing new in industrial circles, Gorilla Glue just did a good job of marketing a good (but often overlooked) product and made it "a thing" among consumers!
Liquid Nails falls into the category of "construction adhesive", but there are many "flavors" of Liquid Nails. Generally, gluing cardboard to wood is easy, so any construction adhesive will work, but I lean towards polyurethane just because I like the way it flows and seals.
Instead of Birch, try asking about "furniture grade" plywood and see if that is a working term in Japan, then inspect what you get. It should have a solid dense feel and inspect all edges to see if there are any voids.
Last, I am relying on Rojo and others to correct me. I am not sure I fully understand the applications.

If you take the tubes to an auto body shop, you might get them to quote painting the plywood as well. Using a body shop may be a bit expensive, but not many people have metal flake paint on their subs. They will likely use some sort of grain filler/sealer on the wood followed by their normal paints which will give you an outstanding finish! A lot of the cost of a small project like yours is getting the paint set up to spray, so you might ask if you can save money by "piggy-backing" on one of the cars scheduled to be painted. Likely if they let you know what colors they will be spraying over the next couple of days, you can find one that would look good on your subs. Last approach them from the standpoint that you are asking a favor - you are not part of their business model. A larger company with a corporate office might have a hard time dealing with the awkwardness of reporting an odd job like yours; whereas with a smaller operation you are dealing with "the CEO".

 

[rojo]

Also I decided to measure the concrete form tube and PVC pipe. The concrete form tube is 30cm ID and 30.8cm OD. The PVC tube is 10.5cm ID and 11.3cm OD. Is any of this an issue?

Not a major one, no. The only thing this affects is your vent length. Cut your PVC vent to 81cm. Your tuning will be maybe 0.15Hz higher than previously planned, but the response curve will be pretty much identical to the previous model (only maybe about 1/2 dB stronger due to the increased effective volume). Thanks for checking the sizes!

 

[Swerd]

I agree with KEW, there are many brands of polyurethane glue available. Google search for polyurethane glue and you'll see what's available where you are. Gorilla Glue is only one brand name and is really not different than most other brands.

http://www.popularwoodworking.com/article/the_truth_about_polyurethane_glue

 

[sleepyhead]

Well this weekend (and in fact most of summer) is festival time, so not much will be done on this project (if at all). Time to get off my face drunk!

But, thanks to@KEW @rojo and @Swerd I'm armed with more knowledge and can make an informed decision. Also, @KEW made a brilliant point about car paint shops: a friend of a friend works at a car tuning shop (mostly drift cars) as a very good painter. Her car is this amazing deep blue! Definitely worth talking to her about. However, coming up is Kansai All Star Drift, so she'll be busy practising for that and arranging the next all girl drift competition in September. I might have to build the subs and leave painting for later? Is that possible or does painting have to be done during the build process?

P.S. If anyone is interested, here is a picture of her car from my Instagram.

P.P.S. As you can see from my Instagram account, I'm also hooked on Pokemon Go. Oops.