Need Help with DIY Subwoofer Selection

A

Argroft

Junior Audioholic
Ok, so I'm relatively new to the whole DIY speaker building world and was looking for some input on selecting and building a subwoofer. The main uses for the sub would be about a 50/50 mix of music and for use in a 5.1 home theater system. My goal is to have a sub that doesn't take up a huge amount of space (doesn't have to be compact, but I'm not looking for something that needs more than 5-7 sq feet of internal volume). I'm looking for something that has a tighter sound but doesn't have to be sealed. I don't know enough about the parameters of drivers to make an informed decision about how to go about this. My other issue is powering this thing. I have a 5.1 receiver that has an output for a powered sub, so if you can recommend an amp, that would be awesome. I know you can get a couple style amps for this kind of thing (plate amps vs a tradition amp that sits on a shelf), but I don't know which is better than the other.

As far as budget is concerned, I don't want to break the bank with this project, but I want to spend enough to get something decent that will last a while. I don't know what a decent subwoofer driver costs, but I'm hoping to spend about $200 or less, but I can be flexible on cost if I need to. I'm hoping to start with a quality setup so I'm not spending this money again a few years down the road. I already built my front and center channel speakers and I am impressed with how they turned out. I'm working on my surrounds now and I'm trying to get the designs for the sub worked out before I'm done with them so I can jump right in, so any suggestions or information you guys are able to provide for me will be greatly appreciated!
 
rojo

rojo

Audioholic Samurai
For an amp, grab one of these Crown amps before they're gone. They're on closeout pricing.

They Dayton HO drivers make nice DIY projects. I'm pretty fond of my CSS sub. The Infinity 1260W would be more efficient than the CSS, but wouldn't handle as much power or offer quite as much max output. Or if you'd like a conversation piece in a miniature footprint, I've been itching for someone to try out my 8" RE Audio Sonosub model. A pair of those would be nice for a smaller room. *shrug* How large is your room in cubic feet?
 
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A

Argroft

Junior Audioholic
Room size is where I run into issues. Currently, I've been setting things up in my bedroom as I still live with my parents (I'm 21). So I have been trying to shoot for speakers that will work well in mid to larger sized rooms. That's also why I am looking for something maybe on the smaller side since I don't know what size room they may ultimately end up in since I may not move out for a couple years. I know that isn't a very good method to follow to choose speakers, but I figured it is my first system and I am by no means an expert when it comes to this stuff.

Also, what amplifier output wattage would you suggest for an amp when I don't have a sub yet?
 
its phillip

its phillip

Audioholic Ninja
http://stereointegrity.com/product/ht18-18-subwoofer/
$174 shipped (CONUS)

http://www.diysoundgroup.com/sealed-subwoofer-flatpacks/4-sub-flat-pack.html
$120 + shipping for an enclosure

http://smile.amazon.com/Behringer-NU3000DSP-BEHRINGER-iNUKE/dp/B005EHINAS/
$280 for this amplifier although many others are suitable as well

Plus however much binding posts/wood glue/duratex (or some other coating)/etc costs

Here's a slightly more expensive alternative to the separate driver + enclosure linked above:
http://www.parts-express.com/dayton-audio-18-ultimax-subwoofer-and-cabinet-bundle--300-7099
 
A

Argroft

Junior Audioholic
http://stereointegrity.com/product/ht18-18-subwoofer/
$174 shipped (CONUS)

http://www.diysoundgroup.com/sealed-subwoofer-flatpacks/4-sub-flat-pack.html
$120 + shipping for an enclosure

http://smile.amazon.com/Behringer-NU3000DSP-BEHRINGER-iNUKE/dp/B005EHINAS/
$280 for this amplifier although many others are suitable as well

Plus however much binding posts/wood glue/duratex (or some other coating)/etc costs

Here's a slightly more expensive alternative to the separate driver + enclosure linked above:
http://www.parts-express.com/dayton-audio-18-ultimax-subwoofer-and-cabinet-bundle--300-7099
I've been preferring to build my own enclosures, I have access to a woodshop with more than enough equipment to do anything I can think up. I only prefer to build my enclosures because it is a great cost-saving step and I can do a bit more customization with the final product. My issue is more selecting the right driver and then figuring out the proper enclosure specs. Building it is the east part!





These are just a couple shots of the speakers I built to use up front. The first one is when I had finished assembling it, the second shot is with the stand I am currently building for them.
 
rojo

rojo

Audioholic Samurai
The Crown XLS 1500 will probably provide enough wattage for any sub you build. Bridged mono it's rated to output 1050W@8Ω, 1550W@4Ω.

I wouldn't relish moving a sub larger than 3 cubic feet. The Infinity 1260w in a 3ft³ box (internal volume) with a 1 1/4" x 12" x 20 5/8" vent would be reasonably manageable, would give you an anechoic F3 of 22.5Hz, and would pump out around 111dB of clean, tight bass with 300W of power.

You're an interesting fellow Argroft. Usually, it's the design that's easy and the build that's intimidating. :) If you'd like to play around with modelling some subs, Install WinISD 0.7.
 
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agarwalro

agarwalro

Audioholic Ninja




These are just a couple shots of the speakers I built to use up front. The first one is when I had finished assembling it, the second shot is with the stand I am currently building for them.
Excellent work! Love the stands.
 
A

Argroft

Junior Audioholic
The Crown XLS 1500 will probably provide enough wattage for any sub you build. Bridged mono it's rated to output 1050W@8Ω, 1550W@4Ω.

I wouldn't relish moving a sub larger than 3 cubic feet. The Infinity 1260w in a 3ft³ box (internal volume) with a 1.25"x6"x22" vent would be reasonably manageable, would give you an anechoic F3 of 22.5Hz, and would pump out around 111dB of clean, tight bass with 300W of power.

You're an interesting fellow Argroft. Usually, it's the design that's easy and the build that's intimidating. :) If you'd like to play around with modelling some subs, Install WinISD 0.7.
I don't have any real issues with moving a large sub. I would rather have a better sounding sub over a smaller one that was built for ease of transportation or room aesthetics. If I'm getting good quality from something that I'd both small and portable, then I'm all for it, but I don't want to sacrifice. So if you still think your suggestion fits that description, then I'm all for it!

As for the amp, I take it that it doesn't matter if the amp can put out a lot more than the driver can handle? I'm used to car audio on the idea that you try to match the sub and amp so they are close on power requirements. Then again I also know that home and car audio are very different subjects.

On a side note, I've never played around with modeling software. Is it easy to use, or at least easy to understand how to use?
 
rojo

rojo

Audioholic Samurai
I don't have any real issues with moving a large sub. I would rather have a better sounding sub over a smaller one that was built for ease of transportation or room aesthetics. If I'm getting good quality from something that I'd both small and portable, then I'm all for it, but I don't want to sacrifice. So if you still think your suggestion fits that description, then I'm all for it!
A properly tuned smaller sub can sound as good as a properly tuned large sub at low volumes. You just have to figure out what compromises you want to make. For example, the Infinity 1260W build is a good all-around build with excellent sound, but won't have the max output of, say, phillip's suggested Stereo Integrity sub; and will easily bottom out in subsonics. If you want absolutely no compromises, buy the Dayton 18" HO driver and build this. The completed Dayton 18" sub will probably weigh 300 pounds, but by God it'll move some air. You'll be able to exceed 118dB with it, not including room gain. If you would prefer subsonic extension rather than max output, then the Stereo Integrity MAG V3 12" in a 2ft³ sealed enclosure would be critically damped and handle the intro to "Edge of Tomorrow" without farting. You'd also need a miniDSP and a calibrated measurement mic to flatten its response, though (which, now that I think about it, would be worthwhile addition to any sub you build); and even with 1000W of power the sealed SI MAG v3 will have less output from 21 - 45Hz than even the Infinity. It's all about compromises.

As for the amp, I take it that it doesn't matter if the amp can put out a lot more than the driver can handle? I'm used to car audio on the idea that you try to match the sub and amp so they are close on power requirements. Then again I also know that home and car audio are very different subjects.
A little extra overhead never killed anybody. Even in cars, I find that more available power makes low-power speakers sound better. I've got an 80wpc RMS amp driving my factory speakers, which are probably, what, max 5W? And it sounds much better than it did with just the factory amp powering them. I don't over-drive them. If they sound harsh, I back off so I don't kill my tweets. Still, I can listen with the windows down on the Interstate. I say all that to say, if you end up driving a 300W sub with a 1500W amp, as long as you don't abuse the sub (letting the driver bottom out till the voice coil mushrooms, or driving it to 120dB until the voice coil fries), there's not much to worry about. In general, it'll sound bad and you'll know to back off on the volume knob before damage occurs.

On a side note, I've never played around with modeling software. Is it easy to use, or at least easy to understand how to use?
*shrug* Learn by doing. In general, you just enter the Thiele-Small parameters of the speaker you want to model, then tell WinISD whether you want to model a sealed, vented, passive-radiator, etc. When modelling vented subs, you'll end up with proper tuning when you tune the box to the Fs of the driver (as can be found in the Thiele-Small params). If you try to tune lower than that, the resulting sub will sound muddy. Also, pay attention to the cone excursion and the rear port air velocity. In general, try to keep the port velocity below 20 meters / second at 125W to avoid audible chuffing I think. A larger vent or multiple vents will slow down the port air velocity, but you'll have to increase the length of the vent at the same time to maintain the appropriate tuning. Just play around with it and enjoy yourself. WinISD is free, anyway; so even if you lose patience with it, you haven't lost anything.

I think the biggest difficulty I encountered with WinISD when I started playing with it was how to enter the T/S params. When you create a new project, if the driver you want to model isn't already in the select list, click Add New. Enter Mfr, Brand, and Model, then click the Parameters tab. This is the tricky part. Some of the values can be auto calculated. If you supply manual values instead of letting the driver editor perform its calculations, you might get an error when you go to save the driver. I generally enter the value for Qes and Qms, then tab twice to let the driver editor auto calc Qts. The value it calculates might not be exactly what the manufacturer supplied in its spec sheet, but it's close enough. Tip: before entering any value after the first two, first you should tab out of the field to see whether it auto populates. If not, then shift+tab to go back and manually enter the value supplied by the manufacturer. If you do this, you'll be able to save your driver with no problems. You can leave the Advanced Parameters and Dimensions tabs untouched if you wish. It's ok to leave some of the values set to 0 if you don't have them and they aren't auto calculated -- like fLe, kLe, Hc, Hg, etc. Also, you may have a value in cubic feet but WinISD is asking for that value in liters, or similar. When that happens, just click the "l" for liters repeatedly to cycle through measurement units (l -> in^3 -> ft^3) until you get to the appropriate unit for the param you wish to enter.
 
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agarwalro

agarwalro

Audioholic Ninja
*shrug* Learn by doing. In general, you just enter the Thiele-Small parameters of the speaker you want to model, then tell WinISD whether you want to model a sealed, vented, passive-radiator, etc. When modelling vented subs, you'll end up with proper tuning when you tune the box to the Fs of the driver (as can be found in the Thiele-Small params). If you try to tune lower than that, the resulting sub will sound muddy. Also, pay attention to the cone excursion and the rear port air velocity. In general, try to keep the port velocity below 20 meters / second at 125W to avoid audible chuffing I think. A larger vent or multiple vents will slow down the port air velocity, but you'll have to increase the length of the vent at the same time to maintain the appropriate tuning. Just play around with it and enjoy yourself. WinISD is free, anyway; so even if you lose patience with it, you haven't lost anything.

I think the biggest difficulty I encountered with WinISD when I started playing with it was how to enter the T/S params. When you create a new project, if the driver you want to model isn't already in the select list, click Add New. Enter Mfr, Brand, and Model, then click the Parameters tab. This is the tricky part. Some of the values can be auto calculated. If you supply manual values instead of letting the driver editor perform its calculations, you might get an error when you go to save the driver. I generally enter the value for Qes and Qms, then tab twice to let the driver editor auto calc Qts. The value it calculates might not be exactly what the manufacturer supplied in its spec sheet, but it's close enough. Tip: before entering any value after the first two, first you should tab out of the field to see whether it auto populates. If not, then shift+tab to go back and manually enter the value supplied by the manufacturer. If you do this, you'll be able to save your driver with no problems. You can leave the Advanced Parameters and Dimensions tabs untouched if you wish. It's ok to leave some of the values set to 0 if you don't have them and they aren't auto calculated -- like fLe, kLe, Hc, Hg, etc. Also, you may have a value in cubic feet but WinISD is asking for that value in liters, or similar. When that happens, just click the "l" for liters repeatedly to cycle through measurement units (l -> in^3 -> ft^3) until you get to the appropriate unit for the param you wish to enter.
You should write a WinISD primer that can be made a stickey.

Thanks for this. I've been wanting to start modeling subs too. Mainly, to educate myself rather than design/build a DIY sub.
 
rojo

rojo

Audioholic Samurai
You should write a WinISD primer that can be made a stickey.

Thanks for this. I've been wanting to start modeling subs too. Mainly, to educate myself rather than design/build a DIY sub.
Glad you found it useful! I don't have much more to say on the subject, though, and I don't really know enough to be able to answer questions about it (like, how does WinISD know to suggest a vented sub rather than sealed, or vice versa; or how are the Pavel Chekov and Quirky Butterbeer alignments useful?).

Actually, a couple of additional tips have sprung to mind, though. When modeling a sealed sub, aim for a Q of 0.5 for servo-like impulse response. Q decreases as the box size increases. When modeling a vented sub, if getting the rear port velocity down below 20m/s at 125W requires unreasonable vent length, find a passive radiator you like and try modeling with that instead. Creative Sound Solutions has a 12" and a 15" I like to model. They both have a high Xmax and will handle up to 1200g of ballast.
 
A

Argroft

Junior Audioholic
Hmm, maybe I've gotten myself in a little over my head with this stuff... I enjoy the building side of speaker building more than the "technical" side. I started off with woodworking like making furniture. I turned to DIY speaker building for several reasons: I could make my own (custom) enclosures for little to no cost, I could get a much higher quality speaker without spending a ton of money, and I would have something that will last a good amount of time without the need to replace it (ha). At this point, I've been researching my builds and opting for the ones that had both good reviews and trusted sources/ designers.

When I started looking into subwoofer design, there doesn't seem to be as many well tested designs. Instead, there's much more custom builds that haven't actually been done before. What I struggle with when it comes to this is a lack of understanding of the parameters of a driver and how they are used to design an enclosure. So you can tell me that a particular sub will outperform because of certain factors, but to be honest, I don't have the knowledge (yet) to understand what exactly it all means. This I why I keep asking some potentially dumb questions, so I appreciate you guys being patient with that and helping me out.

So ultimately, I believe you guys know your stuff, it's just that I like to know what I'm getting myself into (in great detail) before I start working. In all honesty, I question how a sub, like the Infinity 1260w that was originally designed for use in car audio, can function well in a home environment compared to a driver with home theater use in mind. I understand that they both perform the same functions, but what I gathered about car audio anyway, was that it was much more formulated to handle the harsh conditions, moisture and size restrictions like mounting depth that are usually a problem with car audio. In contrast, home audio does not have any of those problems working against it, so the driver can be designed to work it's best without anything to hinder it. So if anyone would like to help me understand this information, it would be greatly appreciated since I don't want to stay uneducated and just follow what other people say because I don't know any better... Thanks!
 
rojo

rojo

Audioholic Samurai
Sub drivers for car audio typically have higher output, but also a higher resonant frequency. You'll typically find car audio enclosures tuned around 40Hz to maximize the output from 40Hz+, so the subs play louder. Below 40-ish Hz, the car's cabin itself acts as another sort of enclosure, supplying additional gain below the tuning of the box. You can see an illustration of this in the graphs provided in the Infinity 1260w spec sheet. More simply, a car subwoofer can do more with less because there's less space to fill. Also, you're likely going to be sitting physically closer to a car sub than a home theater sub. Put a car sub into a 2000 cubic foot typical bedroom, however, and it'll probably struggle to fill that much space below its tuned frequency.

Room gain is less profound than automotive cabin gain, so the tuning of a home theater sub needs to be lower to achieve the same level of rumble. Indeed, there are valleys in the in-room low end response curve where the sub will have no gain at all beyond its anechoic response (partially depending on placement, as corner loading a sub can provide boost you wouldn't achieve from floor and wall boundary loading). Once EQ is applied to flatten the room response, you'll appreciate having a stronger baseline target for your flattening.

This is why, in a home theater or hifi system, it's desirable to have a sub with an anechoic response reaching near or into infrasonics (below ~20Hz). The reason the Infinity in particular can migrate from the car into the home is because it has a relatively low resonant frequency of 23.5Hz. Notice that the Infinity spec sheet recommends a smaller box with a 32Hz port tune. That configuration wouldn't work in a home theater setting, as it's tuned to take advantage of a car's cabin gain. But a 3ft³ net volume (gross would be around 3 1/2 - 3 3/4, depending on wood thickness; displacement of bracing, vent, and driver; etc.) tuned to 23.5 Hz would work well in a home.

I'm still looking for a worthwhile design program that'll let me calculate box dimensions for a desired net volume and visualize how the bracing, slot vent, and so forth will all impact the gross volume. The calculators on this page are pretty useful for figuring out the displacement of the bracing and ports, and for now I guess Google SketchUp would be the way to apply the numbers to a visual model. I haven't had much luck finding a program that'll do both, though. Sonosub does this for tube-based subwoofers (well, lack of braces notwithstanding); but I'd still like to find a similar design program for box sub cabinets. (Edit: Torres' Box Tuning Calculator looks promising. Download w/o registering.)

Nevertheless, you can fudge the tuning a little and compensate with Polyfil if needed. Polyfil will make the sub behave as though it were in a bigger cabinet. And I don't think +- a cubic inch or two will cause a massive unexpected spike or dip in the response that would ruin the whole project. Tapped horns require more meticulous implementation, but I think simple vented subs are more tolerant of imperfection in dimensions. Hopefully @TLS Guy can correct me if I'm wrong.

And yes, if you DIY your sub, you will end up with something that outperforms more expensive subs for less money. If you can DIY, you should. Don't get frustrated and give up!

Playing with WinISD, the HTS web-based calculators, and Torres' Calculator, I came up with this. Build a box out of 3/4" MDF, outer dimensions 19.5"H x 17"W x 24"D (including a double front baffle so you can countersink the driver), build in a 1"H x 15.5"W x 20.75"D slot (no bend needed, using the inner-cabinet bottom and sides as 3 of its walls), and add a brace in the middle (18"H x 15.5"W, 12" hole centered behind the driver). That'll give you net 3.02ft³ internal volume with a vent tuned to 23.83Hz, having a port velocity of ~18m/s at 125W. Dropping in the Infinity 1260w should result in an F3 of 22.5Hz, output of 105dB at 20Hz at 300W at 1m, ~111dB from 29Hz+, and more satisfaction than anyone has a right to expect from a $70 driver. :) Then build a second one, for great justice, and because that Crown amp will easily drive two of those subs. Then get a miniDSP + UMIK-1 to manage them.

Or if you prefer, the Dayton Titanic 15" in a 6ft³ box tuned to 16.8Hz would handle 600W of power, at which point it's about 3dB louder than the Infinity at 30Hz; would have an F3 of 19Hz, and would play down to 14.5Hz (at 107dB with 600W of power) without bottoming out. This would result in a box 24.25"H x 22"W x 28"D with a 2"H x 9"W x 52.75"L vent with a bend or two (I think -- WinISD and Torres seem to disagree about this, with WinISD claiming a length of 25". I can find another calculator to confirm one or the other if you want to pursue this option).
 
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A

Argroft

Junior Audioholic
Alright, so the Dayton Titanic 15" seems like it requires a fairly large enclosure. I have next to no background in home theater subwoofer enclosures, so I don't have any idea what an "average" enclosure is. I do know that sub enclosure sold at big box stores are fairly compact and take up probably 1-2 cubic feet. In a realistic world, how difficult is it to hide a 6ft³ enclosure? I mean it seems rather large to me, but obviously it needs to be the largest enclosure in the system.

In terms of technical specs, how great is a 3dB gain? And how big of a difference is there between the Dayton driver and the Infinity driver? I understand the Dayton driver will out-perform the Infinity, but are there enough gains to justify the cost and size of the larger driver? If so, I am all for going with the larger driver/box, but if it is only a marginal difference with little gain, then I don't see the point. At the moment I am very interested in the design for that Dayton driver. Like I've mentioned before, I want something that will last for a long time and I want to start off with something of good quality and design so I don't have the need to repeat this process in a couple years.

On a side note, I know a lot of people have multiple subwoofers in their system. If I opted for either design, would there be much of an added benefit to having 2 of them? Or would just starting off with a single one and seeing how it performs before making a decision on building a second one? Thanks in advance!
 
rojo

rojo

Audioholic Samurai
Alright, so the Dayton Titanic 15" seems like it requires a fairly large enclosure. I have next to no background in home theater subwoofer enclosures, so I don't have any idea what an "average" enclosure is. I do know that sub enclosure sold at big box stores are fairly compact and take up probably 1-2 cubic feet. In a realistic world, how difficult is it to hide a 6ft³ enclosure? I mean it seems rather large to me, but obviously it needs to be the largest enclosure in the system.
My 3ft³ enclosure is bulky enough. I personally wouldn't want a cabinet larger than that. Then again, as long as the width were the same, since my subs are behind my seats, I'd be OK if it were a few inches higher or deeper. *shrug* But this gives me an idea of what you're looking for, anyway.

In terms of technical specs, how great is a 3dB gain? And how big of a difference is there between the Dayton driver and the Infinity driver? I understand the Dayton driver will out-perform the Infinity, but are there enough gains to justify the cost and size of the larger driver? If so, I am all for going with the larger driver/box, but if it is only a marginal difference with little gain, then I don't see the point. At the moment I am very interested in the design for that Dayton driver. Like I've mentioned before, I want something that will last for a long time and I want to start off with something of good quality and design so I don't have the need to repeat this process in a couple years.
3dB gain is nearly inconsequential. However, the advantage of the Titanic over the the Infinity is subsonic extension. With its lower tuning, the Titanic driver could handle the intro sub arpeggio dropping to 16Hz in "Edge of Tomorrow" at full wattage, whereas the Infinity would bottom out and potentially incur damage on the lowest tone at 75dB or so (if I recall the models correctly). You're right about the box size being a little unreasonable for a bedroom, though.

On a side note, I know a lot of people have multiple subwoofers in their system. If I opted for either design, would there be much of an added benefit to having 2 of them? Or would just starting off with a single one and seeing how it performs before making a decision on building a second one? Thanks in advance!
Adding a second sub would net you ~6dB additional gain, but that's not why people run multiple subs. They do it to smooth out the room response. The room interacts with the sub, with gain in some frequencies and cancellations at others. And as you move around the room, you can hear the changes. Bass that sounds boomy in one spot in the room will sound muted in another. At your primary listening position, adding a second sub allows you to restore the frequencies affected by cancellations and give you more headroom to flatten the peaks. (Flattening the peaks is why I recommended a miniDSP + calibrated measurement mic earlier.)

----------------------------------------------

Anyway, I think I have an option that ticks all the check boxes except budget. I'm still looking around though.

If a manageable enclosure size is a worthwhile consideration to you but you still want a solid performer in a potentially larger room, then the CSS SDX12 does well in smaller enclosures without giving up much subsonic extension. You can eliminate the displacement and added box height required by vents by using a passive radiator, the CSS APR15. That combo would work well in a box anywhere from 1.5 - 2.5ft³. For example, in an 18" cube made from 3/4" MDF (estimating 0.4 cubic feet displacement of a brace, the driver, and the PR loaded with 720g of ballast to net 2.2ft³ internal volume), the F3 would be 21.4Hz. At 500W it plays ~110dB for most of the range, 106dB at 20Hz, and 98dB at 16Hz (below which Xmax is exceeded at that power level). You could make the PR front facing and the driver down-firing, or vice versa, or mount them on opposing sides. It wouldn't really matter.

Or if you prefer not to use a passive radiator, similar tuning can be achieved in a box 21"H x 15.5"W x 23.25"D (made with 3/4" MDF) adding a slot port 1.75"H x 14"W run front-to-back using 1/2" MDF for the vent with 2 turns to a length of 60". Because the vent itself would account for 6 1/4" of the box's height, the box would have to be a bit bigger than the passive radiator option. (Salt to taste with about 1/2 lb. Polyfil I think, depending on the displacement of the bracing you use.)

But I'm still looking for another alternative that might be cheaper while also offering solid performance in a smaller enclosure.

I suppose there's a reason companies like Outlaw, Hsu, Rythmik, Power Sound Audio, SVS, and the like are so well-regarded. They've had years of experience designing subs that offer the deepest extension in the smallest footprint possible. Of course, they achieve this not only with physics but also with electronics.

Speaking of.... You know, if you'd rather have a professionally planned sub project, you could go with the Rythmik DS1200 driver and servo amp combo and build their recommended 3ft³ enclosure. Then again, I'm skeptical whether that offers any obviously audible advantage over their already completed and less expensive LV12R sub, other than the DS1200 having an aluminum cone vs. the LV12R's paper cone.

Here are a couple of nudie pics of both a CSS and a Rythmik build. You might ask @darien87 which project gave him the more satisfying result. I've never heard the Rythmik, but I love my CSS.
 
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rojo

rojo

Audioholic Samurai
Hmmm. The Dayton 12" DVC driver is interesting. In a net 3ft³ internal box tuned to 19.5Hz it seems to handle ~300W of power before reaching Xmax, averaging around 109.5dB. It reaches 20Hz at 106dB and 16Hz at 100dB (xmax limit @ 200W). It's also within your budget. This could be what you're looking for. The vent will require 1 turn I think, and could be handled with an L bend (vent along the bottom, then up the back) 2" x 7" x 29 7/8". I'm liking this one for you. What do you think?

I'm figuring a 19.75" cube external dimensions (single baffle, 0.75" MDF for cabinet and brace, 0.5" MDF for slot vent). Or if you can do a flared PVC pipe on one end, a 4" dia x 26 11/16" length tube (with an elbow) in a 19.5" cube would also work.
 
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A

Argroft

Junior Audioholic
Hmmm. The Dayton 12" DVC driver is interesting. In a net 3ft³ internal box tuned to 19.5Hz it seems to handle ~300W of power before reaching Xmax, averaging around 109.5dB. It reaches 20Hz at 106dB and 16Hz at 100dB (xmax limit @ 200W). It's also within your budget. This could be what you're looking for. The vent will require 1 turn I think, and could be handled with an L bend (vent along the bottom, then up the back) 2" x 7" x 29 7/8". I'm liking this one for you. What do you think?

I'm figuring a 19.75" cube external dimensions (single baffle, 0.75" MDF for cabinet and brace, 0.5" MDF for slot vent). Or if you can do a flared PVC pipe on one end, a 4" dia x 26 11/16" length tube (with an elbow) in a 19.5" cube would also work.
I believe you may be right when you say you think you found the one. That driver is definitely within budget and the box size seems reasonable. I like the idea of going with a flared PVC tube as it would match the design of my current setup a lot better than a rectangular slot. Either way I think this is the most likely setup to fit my needs. Now the only thing left is to get a design on paper and figure out what all accessories (such as amp/dsp/etc.) I'll need to get this to sound it's best (recommendations welcome). Thank you for spending the time to help me out, I greatly appreciate it.
 
A

Argroft

Junior Audioholic
@rojo Since you mentioned the Dayton Audio DVC310-88, I was wondering if you could help me a bit with a couple questions? To start, when using a one ended flare, does it matter what end the flare is on (inside or out)? Also, when measuring the length of a round port with an elbow, does the length go from the center of the circle since depending on the spot measured, it could change the length by a few inches? As far as bracing goes, how was that being implemented? I do know a little about how to brace a sub, but compared to your info, in a 19.5" cubed (external) enclosure the internal volume is 3.375ft³. Once the internal volume of the port is factored out, the volume is 3ft³. When I go to build a box, am I looking for 3ft³ as the gross volume (minus port) or the net volume after driver and bracing is deducted? If bracing and driver displacement were not figured in, then I need a very slightly larger box to account for it. Thanks in advanced!
 
Swerd

Swerd

Audioholic Warlord
I'm not rojo, but I'll take on your questions.
To start, when using a one ended flare, does it matter what end the flare is on (inside or out)?
Keep the flared end of the port on the outside.
Also, when measuring the length of a round port with an elbow, does the length go from the center of the circle since depending on the spot measured, it could change the length by a few inches?
Estimate the overall port length from the center of the port.
As far as bracing goes, how was that being implemented? I do know a little about how to brace a sub, but compared to your info, in a 19.5" cubed (external) enclosure the internal volume is 3.375ft³. Once the internal volume of the port is factored out, the volume is 3ft³. When I go to build a box, am I looking for 3ft³ as the gross volume (minus port) or the net volume after driver and bracing is deducted? If bracing and driver displacement were not figured in, then I need a very slightly larger box to account for it.
Calculate the internal volume of the cabinet based on the T/S parameters. Then estimate the volume taken up by the internal bracing, the port tube, and the driver itself, and add that to the calculated internal volume.

Don't worry, rocket surgery precision isn't necessary here. You can be off by ±10% and it will still work.
 
annunaki

annunaki

Moderator
Lots of great info shared here from the group Argroft!

Personally speaking for the size you are thinking I like the CSS SDX-12. It has loads of Xmax and works well in sealed or vented/PR applications.

There are a number of users of that sub both here and other places.

The Dayton Ultimax is a good comparable alternative but enclosure size will go up quite a bit.

Rojo - thanks for sharing on those Crown Amplifiers! Very good pricing.
 

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