Need help with choosing a budget subwoofer - some used options included

[yonyz]

What if I went the DIY route, but with a flat pack enclosure so I won't have to actually build stuff from scratch? Will $350 get me something nice or is it not worth it in this budget?

 

[rojo]

OK, better musicality. But isn't better extension more important for movies?

In the range of 20 - 40Hz, 3Hz is only a half-step to a whole-step difference -- E to F# or D# to E. I wouldn't worry too much about a sub that plays down to 23Hz as opposed to one that plays 26.

What if I went the DIY route, but with a flat pack enclosure so I won't have to actually build stuff from scratch? Will $350 get me something nice or is it not worth it in this budget?

Going DIY, first thing is you'd have to have a source for drivers and amp. Does the shop near you sell car audio drivers or home audio? Look for something with a Fs (resonant frequency) below 25Hz. Most car audio drivers have a resonant frequency above 30Hz, usually around 40. From there, the build can be as simple as you want if you aren't concerned about pretty. I've even seen one guy build a sub out of a sump basin.

If you get me some brands and models of drivers, I can try to model some for you.

 

[yonyz]

In the range of 20 - 40Hz, 3Hz is only a half-step to a whole-step difference -- E to F# or D# to E. I wouldn't worry too much about a sub that plays down to 23Hz as opposed to one that plays 26.



Going DIY, first thing is you'd have to have a source for drivers and amp. Does the shop near you sell car audio drivers or home audio? Look for something with a Fs (resonant frequency) below 25Hz. Most car audio drivers have a resonant frequency above 30Hz, usually around 40. From there, the build can be as simple as you want if you aren't concerned about pretty. I've even seen one guy build a sub out of a sump basin.

If you get me some brands and models of drivers, I can try to model some for you.

I'm pretty sure they have home audio stuff. I'll have to visit them sometime, but they have shi**y opening hours.

But I was actually thinking of buying a kit from the US. If subwoofers are so expensive here, then so the components should be. Maybe something based on a 10 inch Dayton Ultimax? Its resonant frequency is 26.9 Hz. The 12" version's is at 26.2 Hz.

 

[rojo]

I'm pretty sure they have home audio stuff. I'll have to visit them sometime, but they have shi**y opening hours.

But I was actually thinking of buying a kit from the US. If subwoofers are so expensive here, then so the components should be. Maybe something based on a 10 inch Dayton Ultimax? Its resonant frequency is 26.9 Hz. The 12" version's is at 26.2 Hz.

I've only ever seen kits for building sealed subwoofers. Sealed are less efficient than ported. They're simpler to design and build, but take more effort to EQ. A properly designed ported subwoofer would be better for home theater than sealed. See this post for an illustration of how a sealed sub's response differs from a vented one. Vented subs almost always require a larger enclosure than sealed for proper tuning.

The Infinity 1260w would do very well in this enclosure with a 10cm dia * 46.4cm long vent (requiring one 90° elbow to ensure at least 10cm clearance at the vent opening). That should give it a tuning of ~23.5Hz, an F3 of 23Hz, 106dB on 100W power, 110dB on 300W power, and reaching 18.5Hz at 100dB before hitting xmax at 180W. You'd still have to find an amp, but that design should best everything mentioned thus far, including the SVS PB1000.

 

[yonyz]

I've only ever seen kits for building sealed subwoofers. Sealed are less efficient than ported. They're simpler to design and build, but take more effort to EQ. A properly designed ported subwoofer would be better for home theater than sealed. See this post for an illustration of how a sealed sub's response differs from a vented one. Vented subs almost always require a larger enclosure than sealed for proper tuning.

The Infinity 1260w would do very well in this enclosure with a 10cm dia * 46.4cm long vent (requiring one 90° elbow to ensure at least 10cm clearance at the vent opening). That should give it a tuning of ~23.5Hz, an F3 of 23Hz, 106dB on 100W power, 110dB on 300W power, and reaching 18.5Hz at 100dB before hitting xmax at 180W. You'd still have to find an amp, but that design should best everything mentioned thus far, including the SVS PB1000.

Well what a pleasant surprise. A local dealer sells this subwoofer for just $90, so we're already off to a great start.
Why the Infinity though, and not the Ultimax 12"? It's actually double the price, and that's without shipping and taxes. I wonder why.

How about this amp?
http://www.parts-express.com/yung-sd300-6-300w-class-d-subwoofer-plate-amplifier-module-with-6-db-at-30-hz--301-510

It has an eq of 6db at 30hz for whatever reason. :\
I guess that makes it very limiting? Or perhaps you could adjust the design to compensate for that?
Anyway, anything on Parts Express for roughly the same cost as the amp I linked above - feel free to choose it yourself, because I don't know about that EQ gain stuff.

 

[BoredSysAdmin]

can you find Behringer iNuke1000 amp locally?

 

[yonyz]

can you find Behringer iNuke1000 amp locally?

Locally it's $440. I can import it myself for an overall price of $245.

So I will mention again that my initial budget was $500, I could stretch it a bit if it would allow to build a DIY beast that is even better than an PB-1000. Let's set it at $550, I guess.

So $90 for the woofer, $245 for the amp. We have $215 left, but shipping that 26KG enclosure would cost $167, so overall it's $295.

Can we pick a cheaper amp?

 

[rojo]

Well what a pleasant surprise. A local dealer sells this subwoofer for just $90, so we're already off to a great start.
Why the Infinity though, and not the Ultimax 12"? It's actually double the price, and that's without shipping and taxes. I wonder why.

Ultimax has a bigger magnet and voice coil, beefier suspension, higher excursion, and more power handling. It would actually do pretty well in the same size enclosure as the Infinity, and the two subs model with an almost identical curve below 50Hz with the Infinity offering 2dB more output at 20Hz and 300W due to its slightly lower resonant frequency. But feeding the Ultimax 600W of power will give you output up to 114dB at 35Hz, whereas the Infinity is limited to around 110.5dB. The Infinity models with a much flatter response overall.

How about this amp?
http://www.parts-express.com/yung-sd300-6-300w-class-d-subwoofer-plate-amplifier-module-with-6-db-at-30-hz--301-510

It has an eq of 6db at 30hz for whatever reason. :\
I guess that makes it very limiting? Or perhaps you could adjust the design to compensate for that?

Cheap Chinese crap, and the built-in DSP will do more harm than good. It's probably meant to make a sealed sub a bit flatter -- but a boost like that eats into overall power. Think of it that the amp's strongest 300W output will be at 30Hz, at a reference 0dB. But that reference is a hill. The valleys around the hill are -6dB, or 300W * 1/2 * 1/2. That amp probably puts out about 75 watts at 20Hz and above 50Hz or so.

Anyway, anything on Parts Express for roughly the same cost as the amp I linked above - feel free to choose it yourself, because I don't know about that EQ gain stuff.

The Behringer iNuke that BSA linked really will offer the best output for the money. Maybe ordering a flat pack isn't the best idea if you can source 1.9cm hardwood plywood or medium density fiberboard locally. Are there any local cabinet shops you could pay to build you a copy of the flat pack? It might be cheaper than shipping a bunch of wood overseas. If you don't have a good source for lumber or are uncomfortable with your woodworking skills, you might consider a concrete form tube or a sump basin. Do you have anything like this basin available? If so, how many liters does it hold? Does it have an available lid you could cut a hole in for the driver and seal with expanding glue? If not, do you have anything like this concrete form tube available? You'd still have to create your own end caps for it -- or, again, a local cabinet maker, car audio shop, or other wood worker might be willing to cut a few circles for you for a reasonable price. And if you put in a bit of time and effort in finishing it, a sonosub can be made to look beautiful.

But if you aren't ready for a lot of effort and patience to build or assemble your own sub, I still vote for the GoldenEar.

 

[yonyz]

Ultimax has a bigger magnet and voice coil, beefier suspension, higher excursion, and more power handling. It would actually do pretty well in the same size enclosure as the Infinity, and the two subs model with an almost identical curve below 50Hz with the Infinity offering 2dB more output at 20Hz and 300W due to its slightly lower resonant frequency. But feeding the Ultimax 600W of power will give you output up to 114dB at 35Hz, whereas the Infinity is limited to around 110.5dB. The Infinity models with a much flatter response overall.



Cheap Chinese crap, and the built-in DSP will do more harm than good. It's probably meant to make a sealed sub a bit flatter -- but a boost like that eats into overall power. Think of it that the amp's strongest 300W output will be at 30Hz, at a reference 0dB. But that reference is a hill. The valleys around the hill are -6dB, or 300W * 1/2 * 1/2. That amp probably puts out about 75 watts at 20Hz and above 50Hz or so.



The Behringer iNuke that BSA linked really will offer the best output for the money. Maybe ordering a flat pack isn't the best idea if you can source 1.9cm hardwood plywood or medium density fiberboard locally. Are there any local cabinet shops you could pay to build you a copy of the flat pack? It might be cheaper than shipping a bunch of wood overseas. If you don't have a good source for lumber or are uncomfortable with your woodworking skills, you might consider a concrete form tube or a sump basin. Do you have anything like this basin available? If so, how many liters does it hold? Does it have an available lid you could cut a hole in for the driver and seal with expanding glue? If not, do you have anything like this concrete form tube available? You'd still have to create your own end caps for it -- or, again, a local cabinet maker, car audio shop, or other wood worker might be willing to cut a few circles for you for a reasonable price. And if you put in a bit of time and effort in finishing it, a sonosub can be made to look beautiful.

But if you aren't ready for a lot of effort and patience to build or assemble your own sub, I still vote for the GoldenEar.

So it sounds like the Infinity will do just as well as the Ultimax in this specific model. Am I correct or is there more to subs than frequency response?

I don't even know what a basin is in Hebrew.

I will contact a woodworker and ask for a price estimate using the dimensions on the Parts Express website. What about the hole that needs to be cut for the woofer, and the port itself?

How do I make the port/tube? Is it also a woodworker's job or is it made of plastic?

As for the Behringer amp, I noticed it has no RCA connectors at all. Does it have line level inputs and outputs? Because I don't have a receiver, which means I'll also need a crossover on the amp itself.

The GoldenEar does seem like the easier and far more elegant solution, but the guy said it might be for sale "within the coming weeks". He didn't specify a price either, so...

 

[rojo]

So it sounds like the Infinity will do just as well as the Ultimax in this specific model. Am I correct or is there more to subs than frequency response?

Hard to say; but Harman International, parent company of Infinity, has a good reputation of bringing science to music, and the 1260w has been featured in lots of DIY builds with great success. And so has the Ultimax. I'm sure the Ultimax will handle more voltage before exhibiting non-linear BL(x) and harmonic distortion, but the Infinity 1260w is a capable driver.

I don't even know what a basin is in Hebrew.

אַגָן or כִּיוֹר or קְעָרָה or שׁוֹקֶת I guess? Sorry if those glyphs get converted to left-to-right order when I post. Anyway, the purpose of that sump basin is for holding a water pump, connecting exit plumbing from an underground basement or cellar to the city sewer line. But it's cylindrical and strong walled, so it should do well as a subwoofer enclosure without bracing.

I will contact a woodworker and ask for a price estimate using the dimensions on the Parts Express website. What about the hole that needs to be cut for the woofer, and the port itself?

How do I make the port/tube? Is it also a woodworker's job or is it made of plastic?

The best way to cut the driver hole will be with a drill and a plunge router. The port might be cut with a 10mm hole saw attached to a drill or a router, but the edge should be flared (rounded over) with a router.

The tube is probably going to be 10mm PVC pipe. It's white plastic pipe usually used for plumbing.

As for the Behringer amp, I noticed it has no RCA connectors at all. Does it have line level inputs and outputs? Because I don't have a receiver, which means I'll also need a crossover on the amp itself.

It does have inputs and outputs. You can use a simple adapter to adapt an RCA cable pair to a pair of TS plugs -- something like these. The Behringer amp has Speakon jacks for output. You'd use a Speakon cable from the amp to the sub, where you'd have a Speakon plug mounted. Inside the cabinet, connect the Speakon plug to the subwoofer driver with speaker wire.

The GoldenEar does seem like the easier and far more elegant solution, but the guy said it might be for sale "within the coming weeks". He didn't specify a price either, so...

Ah well. Hey, do you think your courier could get you an RSL Speedwoofer within your $550 limit? They're $400 with free shipping in the US.

 

[yonyz]

Hard to say; but Harman International, parent company of Infinity, has a good reputation of bringing science to music, and the 1260w has been featured in lots of DIY builds with great success. And so has the Ultimax. I'm sure the Ultimax will handle more voltage before exhibiting non-linear BL(x) and harmonic distortion, but the Infinity 1260w is a capable driver.



אַגָן or כִּיוֹר or קְעָרָה or שׁוֹקֶת I guess? Sorry if those glyphs get converted to left-to-right order when I post. Anyway, the purpose of that sump basin is for holding a water pump, connecting exit plumbing from an underground basement or cellar to the city sewer line. But it's cylindrical and strong walled, so it should do well as a subwoofer enclosure without bracing.



The best way to cut the driver hole will be with a drill and a plunge router. The port might be cut with a 10mm hole saw attached to a drill or a router, but the edge should be flared (rounded over) with a router.

The tube is probably going to be 10mm PVC pipe. It's white plastic pipe usually used for plumbing.



It does have inputs and outputs. You can use a simple adapter to adapt an RCA cable pair to a pair of TS plugs -- something like these. The Behringer amp has Speakon jacks for output. You'd use a Speakon cable from the amp to the sub, where you'd have a Speakon plug mounted. Inside the cabinet, connect the Speakon plug to the subwoofer driver with speaker wire.




Ah well. Hey, do you think your courier could get you an RSL Speedwoofer within your $550 limit? They're $400 with free shipping in the US.

Lol, I'd rather not go the sump basin way.

So the driver hole is also a job for the woodworker. What dimensions do I give him? Just 12 inch?
And where should the woodworker put the bracing? Does it have to be exactly like on the Parts Express enclosure you linked before?

I'm not quite sure as to how I would connect my speakers. They're active speakers ("monitors"). Can I connect my DAC to the power amp, and then the amp would output an amplified signal to the sub up to a certain frequency, and the rest of the signal to the speakers, without amplification? Is this possible?

Last one: since a woodworker will build my enclosure, can we optimize its design someone? I think I prefer the shape of the PB-1000, with the port and woofer near each other, as opposed to a perfect cube where the woofer takes up a whole side.

Edit: Almost forgot. There's 35% overall tax on speakers/subs, so that would make the Speedwoofer $540 before shipping. I couldn't find its weight to calculate shipping, but it would be at least $100.

2nd Edit: Oh and about the braces in the enclosure, must they look identical to the smooth and curvy ones on the Parts Express enclosure? Or could it just be an "X" in the middle of the enclosure? I'm sure that would be cheaper to make...

 

[rojo]

Lol, I'd rather not go the sump basin way.

So the driver hole is also a job for the woodworker. What dimensions do I give him? Just 12 inch?
And where should the woodworker put the bracing? Does it have to be exactly like on the Parts Express enclosure you linked before?

I'm not quite sure as to how I would connect my speakers. They're active speakers ("monitors"). Can I connect my DAC to the power amp, and then the amp would output an amplified signal to the sub up to a certain frequency, and the rest of the signal to the speakers, without amplification? Is this possible?

Last one: since a woodworker will build my enclosure, can we optimize its design someone? I think I prefer the shape of the PB-1000, with the port and woofer near each other, as opposed to a perfect cube where the woofer takes up a whole side.

You could split the output from the DAC with half going to the active monitors and the other half going to the sub, but that signal will be full range. The Behringer NU1000 offers a low-pass filter, but it's stuck at 100Hz. If that's unacceptable, then maybe a plate amp with a selectable crossover frequency would be a better choice. Here's an interesting plate amp that has a filtered pass-through. Run RCA from your DAC to your subwoofer, then RCA from your subwoofer back to your active monitors. The amp sends low-pass signal to the subwoofer and high-pass signal to your monitors. It's still cheap Chinese crap, but there aren't many plate amps that aren't. (The amp mounts to the back of the subwoofer cabinet and requires a 231mm * 179mm cutout).

Here's the manual for the Infinity 1260w. The cutout diameter for this driver is 282mm.

Yeah, the box can be any shape you want as long as its internal volume remains roughly the same. It needs to be roughly between 70 and 85 liters, and the length of the port will need to be tweaked depending on the box size. If you decide you want a box that's, say, 38cm (W) * 61cm (H) * 45cm (D) external dimensions, subtract 4cm from each dimension assuming you're using 2cm thick wood. That leaves you with an internal volume of roughly 79.5 liters. Subtract the displacement of the driver and vent, and you'll have around 75 liters. Subtract the displacement of the bracing and you'll have around 70 liters, still acceptable. The height of the enclosure would give you plenty of space to place both the driver and the vent on the front baffle.

If you like those dimensions, then I'll model it and calculate the length of a 10mm vent to result in the tuning of 23.5Hz which that driver needs.

 

[yonyz]

Whoa, so many numbers.

The dimensions for the PB-100 are (in inches): 15 x 18.4 x 18.4. Can we use these or is it too small?

I'd rather not go with a generic amp, certainly not one from AliExpress.
What about the NU1000DSP? Does it allow modifying the crossover?

And this? http://www.parts-express.com/yung-sd300-300w-class-d-subwoofer-plate-amplifier-module-no-boost--301-508

300W, no boost, good reviews, similar price to the Nuke 1000. How many watts do I actually need?

 

[rojo]

Whoa, so many numbers.

The dimensions for the PB-100 are (in inches): 15 x 18.4 x 18.4. Can we use these or is it too small?

I'd rather not go with a generic amp, certainly not one from AliExpress.
What about the NU1000DSP? Does it allow modifying the crossover?

And this? http://www.parts-express.com/yung-sd300-300w-class-d-subwoofer-plate-amplifier-module-no-boost--301-508

300W, no boost, good reviews, similar price to the Nuke 1000. How many watts do I actually need?

The Infinity driver is a 12", whereas the PB1000 uses a 10" driver. A bit larger box is to be expected. But the dimensions of the example I suggested above are almost exactly the same width and depth, just with 14cm added height. Are you more comfortable with imperial measurements or with metric?

300W at 4 ohms is an ideal rating for this sub. The Yung amp you found would work fine. The NU1000DSP would be excellent, and yes, it allows modifying the crossover frequency; but you'd have the added expense of an uncommon Speakon cable and cabinet terminal, and your monitors will still run full-range. The Yung amp happens to be out of stock, but this similar Dayton amp would be a worthwhile substitute. It has an advantage of running with constant power, so periods of silence or very light bass won't let the amp fall into standby if you select the "manual on" power setting.

 

[yonyz]

The Infinity driver is a 12", whereas the PB1000 uses a 10" driver. A bit larger box is to be expected. But the dimensions of the example I suggested above are almost exactly the same width and depth, just with 14cm added height. Are you more comfortable with imperial measurements or with metric?

300W at 4 ohms is an ideal rating for this sub. The Yung amp you found would work fine. The NU1000DSP would be excellent, and yes, it allows modifying the crossover frequency; but you'd have the added expense of uncommon Speakon cables, and your monitors will still run full-range.

OK. If it's just another 14cm for the height, then okay. It will do.

I just read a really bad review of the Yung amp. A guy bought 2 and both had a blown fuse over time, one within the warranty period. I'm not gonna have any kind of real warranty with an overseas purchase so it's a big risk.

I found this:
http://www.parts-express.com/refurbished-bash-500s-500w-digital-subwoofer-amplifier--88-300-752#lblProductDetails

However, it's only 120V. I wonder if there's an internal jumper that can be switched, because BIC America told me their PL-200 has one.

Lastly, there's this, but it's 250W. Ticks all the other boxes, though.
http://www.parts-express.com/dayton-audio-spa250-250-watt-subwoofer-plate-amplifier--300-803

I plan on visiting a wood shop tomorrow morning to get a price estimate.
So I need to make a list of all the wood pieces that need to be cut. Could you help me with their dimensions?

The wood shop also needs to cut a port and a driver hole, correct?

And regarding the thickness, you said before 1.9cm and then 2cm, and I wonder if that makes any difference.

My assumption is that it would be significantly cheaper than importing the enclosure from parts express, so maybe that would allow me to get a better amp, like a Dayton 500W, which has proper 120/230V support.

 

[rojo]

...but this similar Dayton amp would be a worthwhile substitute.

Lastly, there's this, but it's 250W. Ticks all the other boxes, though.
http://www.parts-express.com/dayton-audio-spa250-250-watt-subwoofer-plate-amplifier--300-803

Great minds think alike!

I plan on visiting a wood shop tomorrow morning to get a price estimate.
So I need to make a list of all the wood pieces that need to be cut. Could you help me with their dimensions?

The wood shop also needs to cut a port and a driver hole, correct?

And regarding the thickness, you said before 1.9cm and then 2cm, and I wonder if that makes any difference.

My assumption is that it would be significantly cheaper than importing the enclosure from parts express, so maybe that would allow me to get a better amp, like a Dayton 500W, which has proper 120/230V support.

The driver and amp are already pretty well matched. Spend the money on a nicer finish. Maybe get some wood veneer for the faces of the box without holes.

For a cut list, it's not hard to figure out. Just take width and depth, and those are the dimensions of your top and bottom. Depth and height, those are the two sides. Width and height, that's the front and back. Cut holes for the driver, plate amp, and vent wherever you want them. If your wood shop can round over the edge of the vent hole, have them do it. You could also get feet and make the subwoofer bottom firing for a cleaner look if you prefer. The bracing, there's no set formula. Just brace each long panel at its center to divide its resonating surfaces in half.

The purpose of the bracing is that a long and wide panel can vibrate at its resonant frequency. Such a panel with a brace in the middle will have two halves that vibrate at a much higher frequency, hopefully beyond the range the subwoofer plays. The braces shown in the Parts-Express knockdown boxes are a pretty good design, offering solid bracing with minimal displacement. Some people use more involved bracing techniques.

I said 1.9cm because in the U.S. our plywood and MDF is often sold in 3/4-inch thickness, and 3/4 inches is roughly 1.9cm. Then I figured Israel might be more likely to use 2.0cm as a standard thickness because you guys aren't weird like we are. Whichever, a millimeter isn't going to make a profound difference in the tuning I don't think.

If you prefer, the sub can be built with a slot port rather than a vent. There's no reason the vent has to be round, and a slot port might be easier to fold. Do you have a preference? Also, I'm still curious whether you prefer measuring in inches and cubic feet, or centimeters and liters.

 

[yonyz]

Great minds think alike!



The driver and amp are already pretty well matched. Spend the money on a nicer finish. Maybe get some wood veneer for the faces of the box without holes.

For a cut list, it's not hard to figure out. Just take width and depth, and those are the dimensions of your top and bottom. Depth and height, those are the two sides. Width and height, that's the front and back. Cut holes for the driver, plate amp, and vent wherever you want them. If your wood shop can round over the edge of the vent hole, have them do it. You could also get feet and make the subwoofer bottom firing for a cleaner look if you prefer. The bracing, there's no set formula. Just brace each long panel at its center to divide its resonating surfaces in half.

The purpose of the bracing is that a long and wide panel can vibrate at its resonant frequency. Such a panel with a brace in the middle will have two halves that vibrate at a much higher frequency, hopefully beyond the range the subwoofer plays. The braces shown in the Parts-Express knockdown boxes are a pretty good design, offering solid bracing with minimal displacement. Some people use more involved bracing techniques.

I said 1.9cm because in the U.S. our plywood and MDF is often sold in 3/4-inch thickness, and 3/4 inches is roughly 1.9cm. Then I figured Israel might be more likely to use 2.0cm as a standard thickness because you guys aren't weird like we are. Whichever, a millimeter isn't going to make a profound difference in the tuning I don't think.

If you prefer, the sub can be built with a slot port rather than a vent. There's no reason the vent has to be round, and a slot port might be easier to fold. Do you have a preference? Also, I'm still curious whether you prefer measuring in inches and cubic feet, or centimeters and liters.

No bottom firing for me. I love the look of woofers.
You mentioned multiple times that the vent should be 10mm, and I think you meant 10cm? 10mm would be like a finger.


I'm a bit confused about the bracing. I made a terrible sketch of the box, and I'm not sure where the braces go.

https://s31.postimg.org/cvgyblvln/IMAG0301.jpg

 

[rojo]

No bottom firing for me. I love the look of woofers.
You mentioned multiple times that the vent should be 10mm, and I think you meant 10cm? 10mm would be like a finger.


I'm a bit confused about the bracing. I made a terrible sketch of the box, and I'm not sure where the braces go.

https://s31.postimg.org/cvgyblvln/IMAG0301.jpg

Yes, I did mean 10cm. Sorry about that.

You're not wrong about your sketch. But it is effective enough, as long as the finished product doesn't look like that.

This is one way to do the brace:

In that rendering, the brace and all panels are 2cm thick. The cutouts in the bracing will be 14cm x 17.5cm if my drawing is accurate, but I'm not confident enough with SketchUp to say that those values are exact. The (10cm!) vent length should total 535mm, so you'll have to use a 90-degree elbow in your PVC pipe and run part of it up through the brace. Note: Don't forget to ask if they can round over the exterior edge of the 100mm hole. It also might not be a bad idea to double-check your available 10cm PVC pipe and see whether 10cm is an internal diameter or external. I modeled assuming that's internal diameter. If it's external, we'll have to re-do some measurements -- not only for the size of hole to cut, but also for the length of the vent.

With 250 watts of power, this sub should hit 110dB at 1 meter, it'll have a -3dB point near 23.8Hz, and hit 19Hz near 102dB before reaching its excursion limit. With room gain, the output will be even higher. This should be a very nice sub.

 

[yonyz]

Yes, I did mean 10cm. Sorry about that.

You're not wrong about your sketch. But it is effective enough, as long as the finished product doesn't look like that.

This is one way to do the brace:

In that rendering, the brace and all panels are 2cm thick. The cutouts in the bracing will be 14cm x 17.5cm if my drawing is accurate, but I'm not confident enough with SketchUp to say that those values are exact. The (10cm!) vent length should total 535mm, so you'll have to use a 90-degree elbow in your PVC pipe and run part of it up through the brace. Note: Don't forget to ask if they can round over the exterior edge of the 100mm hole. It also might not be a bad idea to double-check your available 10cm PVC pipe and see whether 10cm is an internal diameter or external. I modeled assuming that's internal diameter. If it's external, we'll have to re-do some measurements -- not only for the size of hole to cut, but also for the length of the vent.

With 250 watts of power, this sub should hit 110dB at 1 meter, it'll have a -3dB point near 23.8Hz, and hit 19Hz near 102dB before reaching its excursion limit. With room gain, the output will be even higher. This should be a very nice sub.

Wow, this sketch will save me a lot of explanation due to poor drawing skills.
Thank you!

BTW, do you have the project file for this sketch and can share it?

Thanks again.

Edit:

Got off the phone with a woodworker. I forgot to mention the port flare thing, but I doubt it would make much of a difference in the cost. Without any polish or painting, the cost is $121. He says he's got 18mm MDF, not 2cm. Will it do?

I've also sent emails and faxes to another 3 or 4 wood shops but they seem to focus mainly on kitchens and not "special" projects.

Can I do the polish myself or will I need special tools? Will lacquer and paint do the trick?

Edit 2: My calculation puts the overall cost at 1896 NIS which are $490. Will upping the budget to $600 get me something better?

 

[rojo]

Attached to this post you'll find the SketchUp project file. I had to rework the brace. In the models I made last night I couldn't figure out how to give depth to the side wall, so the dimensions of the brace were a bit off. It should be better now.

Paint and lacquer will be fine, or you can veneer the top and sides for a nicer finish. Is the wood shop going to assemble and glue the cabinet for you as well? Will they also cut and glue in the vent for you?

Changing the wood from 2mm to 1.8mm only adds about a liter to the total internal volume (and adding volume is certainly more welcome than displacing volume). The vent tuning at 535mm is still close enough. The brace might need a couple millimeters added to each dimension to be perfect, but I'm sure the wood workers will know how to handle the variance. Or just leave the millimeter gap on each side and glue it in with Gorilla Glue or some other type of expanding glue. (Just don't use Gorilla Glue on the seams that might leak outside the box. I made that mistake with my CSS SDX12 subwoofer. Click the link in my signature to see pics of Gorilla Glue done badly.)