Dustin B

Unless you can get it for less than half what Crutchfield wants I wouldn't bother. The Adire Shiva and Dayton DVC12" will both definately match if not exceed it for around $125 shipped. If you want a little more capable driver go for a Dayton Titanic MKII 12" for $150. For roughly the same output but deeper in a smaller sealed box look at the Adire DPL12 for around $150. And for what that Infinity is worth look at the Stryke AV12. Significantly more displacement and I think you can still get the preorder price on it of $165. Also, powerhandling doesn't prevent bottoming. A Tempest can handle over 700W, but in an EBS allignment 250W will be capable of bottoming it. Pretty much every driver out there will bottom before you hit its thermal power handling limits. The exceptions being some extremely long throw drivers in small sealed boxes.

Paradigm would be significantly more expensive if you ordered it from the states. For the most part the US and Canadain Paradigm prices you can get are the same. But the values of the currencies which represent those prices are very different.

Rava won't have the same kick as the PS series bandpass (shiver, bandpass) boombox. But the Rava is a sealed 0.67Q Shiva with a 250W plate amp. It will have respectable output down to 30hz where it has a some what gentle but consistent roll off, but the sound quality will be great. Should be able to get a better price than that on the PS1200. Infact if he can get is budget up to the mid $800CDN range the PW2200 would be possible with some haggling. Would be the option I'd recommend for him.

Tempest AVA250 is exactly what I have. It's way more sub than the Promedia's could keep up with. The jist of it was I would put a base plate on it for appearence reasons (would also make moving it easier). I wouldn't bother with the threaded rod. And I might attempt to flush mount the amp. There are some other more minor construction specific things listed on my webpage.

Not really, but unless you have a seperate amp you won't be able to not use the Promedia's subwoofer.

The AVA250 has inputs for both the left and right channel. So you could put a Y on both the left and right channel outputs of your sound card. But this will only get you a low pass filter, your mains will still be getting a full range signal. It won't give a great response curve but it will definately get you bass.

Depends on the soundcard. But even if it has a sub output (would be on the 5.1 break out cables) I highly doubt it will have any bass management. Without bass management only sources with a dedicated LFE signal will feed it bass. There are hacked drivers for M-Audio cards that will provide pretty good bass management though.

If this is for car use you may want to consider returning the Shivas and getting a single 12" Brahma from Adire instead. Will cost you a little more than a pair of Shivas, but will work in a much smaller box and be able to compete with the output of a pair of Shivas and easily best them in sound quality. Couple other comments. You can't bridge a QSC amp into a 2ohm load (well you could probably run them bridged at 2 ohms, but don't expect to be able to push them). They can run 2 ohm loads in stereo, but when bridged can only handle 4 ohm loads. Also don't get too hung up on power handling. Remember a driver has thermal limits and excursion limits that are both related to power input. The vast majority of the time the driver will reach it's excursion limits long before it reaches it's thermal limits. Especially drivers like the Shiva and Tempest. The XBL^2 drivers from Adire are a different story though. There are suitable allignments for these drivers that can ask for power that approaches the drivers thermal limits. Good thing it's so high on those drivers.

Just make your own: http://www.nch.com.au/tonegen/

It's all about cabin gain. If you put any decent home sub in a room the size of a car cabin it will match or kick the crap out of most car audio subs. None of the subs you're friends listed are what I'd consider top notch. Adire, JL Audio, Image Dynamic among a few others make good drivers for car use. A single Tempest with 500W in a truck cab has broken 150dB. The same config in a typical living room won't be able to break 120dB. Done well it is possible to get good sound in a car, but very few people do it well.

If you are talking Canadian dollars, then yes that sounds about right. I was talking about total cost in US funds. I outline my actual costs on these two pages. http://dustin.bunnyhug.net/cost.php http://dustin.bunnyhug.net/twincost.php I could do it for less knowing what I know now, and with CSS in existance. http://www.creativesound.ca $240CDN including shipping for a Tempest. $270CDN for the AVA250 plus a marginal shipping charge (depends on what shipping option you go for). So even including taxes that shoudn't pass $575CDN. Another $175CDN max for building materials (a lot less if you can find a construction site with appropriate scrap they are willing to just let you take). Total is $750CDN for the completed sub. PW2200 would run you another $50 to $200 after taxes (depending on the deal you get). It also won't sound as good, wouldn't have anywhere near the extension and it would really take 2 of them to compete in output from the second octave and up with a well built Tempest. The Servo15 could compete extension wise (and sound quality wise if you don't mind what a servo does to the sound), but again it would take two of them to compete with output. So $750 DIY vs $1600-$3000 for something comprable from Paradigm

I am. Unless you have to buy tools the the cost will be more like $300-$500 for the subs I built. The smaller ones are nice (easily on par with a PW2200, just play lower and sound a little better), but they can't compete with the larger one. The Shiva vs the Tempest just isn't a fair fight. Lower Fs, larger Vas, slightly more Xmax and a lot more surface area. The Tempest has roughly 66% more Vd than the Shiva. Output wise a Tempest will destroy a PW2200, especially down low. My Tempest is also no slouch with sound quality. The low tune gives up some punch, but I gain a very clean response and great low end rumble. Guess I should caveat with both, as long as you tune them low. The smaller ones are tuned to 20hz and the big one is tuned to just over 16hz. Tune the smaller one (and make it even a little smaller) up closer to 30hz and you'll have the equivalent of a PW2200 more or less. I don't think the CHT12 is as good as a PW2200.

I seem to remember someone who knows a lot more about horns than I saying those are closer to a bandpass design (especially the wicked1) than a horn. Those designs don't have a large enough mouth and the horn path is too short. If you want to build a basshorn check out the Lab12 designed by Tom Danley. http://www.prosoundweb.com/lsp/ As for DIY competing with commercial. The vast majority of commercial subs are seriously hampered by the design constraints placed on them. Size, weight and price. Doesn't matter how much R&D you do, still can't get around Hoffman's Iron law (at least not yet). With the help of experienced hobbiests (some I wouldn't call hobbiests though, I'd call them professionals) it is very easy to build a sub that will easily outclass any commercial sub at the same price point (often at price points 2-4x higher).

Somewhere in the 40-100 litre range should work well for a sealed enclosure. Just build it very strong. Head over to the DIY section of hometheaterforum.com and Anthony G or Brian Bunge (as well as Dan W at Adire) will be able to help you out with the specifics of enclosure size, how much power you'll need and getting your hands on a LT circuit. Also remember that the driver is roughly 12" deep and should have some space for the pole piece to vent out the back. So make sure your risers will be tall enough to accommodate this beast.

Properly done I don't think this driver would have problems keeping up with a pair of Ultras.

Best pics are here: http://www.acoustic-visions.com/tumult.htm Company that makes it (same company that makes the Shiva and Tempest): http://www.adireaudio.com/diy_audio/drivers/adire/tumult.htm This driver is a beast. Driver by itself is 49lbs. Little over 5.1L of very linear Vd (to match the output of this driver at the same distortion level would require roughly 3 Tempests). Would not be hard to build a sub with this driver that will easily outclass a Krell MRS. But it's not cheap at $500 a pop.

You could also sell your two RSW subs and build a pair of sealed Tumults with Linkwitz Transform circuits, a nice EQ and a QSC PLX3402. With an appropriate LT circuit you can have extension to below 20hz and with the XBL^2 motors and a sealed allignment the sound will be amazing. Highly doubt you'd miss either RSW with those. And if you wanted more bass, just go to a less powerful amp, forget the LT circuit and buy 4 of Styrke's dual spider 18" passive radiators. Enclosures will need to be a little bigger, but a pair of Tumults in an appropriate passive radiator allignment will be scary.

AV15 is $205 (unless you can still finagle the preorder price, forget what that is but a chunk cheaper). The amp will be another $130-$500 depending on which one you go with and $50 for a pair of 6" port flares. Add to that whatever you spend on the enclosure and finish. Tumult is $500. PRs are something like $120 each. Amp will be $400-$1200 depending on what you go with. Plus enclosure and finish.

At the time, only things I'd to differently are put a base plate and round legs on it (appearance reasons only). Might also have flush mounted the amp. Right now, little harder to say. Given my budget constraints I would still likely stick with the Tempest. Although if I could spend some more I'd likely go with a Stryke Audio AV15, some 6" port flares and a 350-500W plate amp. If I could spend a lot more Adire Tumult with a pair of 18" dual spider passive radiators and over 1000W pro amp. Althoug my dream is still for Adire to come out with an XBL^2 motor topology (Adire's patent pending design that is very cool) Tempest that would have around 3L of Vd. Then I'd like to put 4 of them in an infinite baffle sub. It's bottom on my list right now, but hopefully by the time I'm ready, Dan will have the drivers out First on the list is a Panasonic PT-L300U and a HTPC

Excellent post William. One of the best simple explanations of what's going on I've every read. Doubly so on the simple part since I get the feeling from your post that your knowledge level goes way over mine.

Thanks, it sounds kick *** too. Amazing what can be done when you can let Hoffman's Iron law dictate enclosure size to you. Just wish my receiver would get back from the repair place fixed, a month with no stereo really sucks.

Yes it is.

That's just asking for trouble. Please read the Stryke PR FAQ. It will answer all your questions. There are some group delay rises associated with a PR. A PR just can't respond as fast as the slug of air in a port (that's right, air doesn't flow through the port, a slug of air vibrates back and forth). If both are well done I doubt you could tell the difference, but part of being well done is getting the tuning frequency low enough that the associated rise in group delay is with inaudible frequencies. Now the Ears beloved Aerial SW12 is underported and will have the port noise problems down low. As long as the air speed stays below 17m/s in a striaght port (like it does in my DIY Tempest) and below ~25m/s with a flared port you won't experience compression and/or port noise. Also remember that PRs have excursion limits and can create problems like port compression when they are asked to travel farther than they can linearly.

http://www.danmarx.org/audioinnovation/theories.html Give that a read, may help your understanding a little. No you can't put a port in an RSW. It already has one with the passive radiator. This will help with your understanding on that point: http://www.stryke.com/prfaq.htm Like I said in your other post. The RSW series is tuned much higher than SVS subs. That is what gives it the punch and the lack of extension. If you wanted you could try and add some weight to the PR on the RSW to lower it's tuning point, but that's dangerous since you don't know how much is on it and how much it can handle.

Driver size has nothing to do with how low it will play. A tweeter can be designed to play a 20hz tone. Problem is the tweeter will be moving so little air you won't be able to hear it. Two things have to happen to produce low bass, the driver has to be designed to play it, and the driver has to be able to move enough air that we can hear it. With acoustic suspension and bass reflex systems the key volume down low is displacement (Vd). Vd is the multiple of the cones effect radiating surface area (Sd) and the distance the driver can travel linearly (two way Xmax). So if a smaller driver can travel sufficientyly farther than a larger driver it will be able to move more air. So in the case of comparing a KSW15 driver to a TV12 (driver in the Ultra), the TV12 will easily move a significantly larger amount of air. But compare a TV12 to a driver like Adire's 15" Tumult and the TV12 will be way behind because it has a smaller Xmax and almost half the Sd. The other point to remember is Hoffman's Iron law. Out of efficiency (how much power is needed), extension (how low the sub will play) and enclosure size (how big the box needs to be), you can pick any two to control and the third will be dicated to you. Small box and extension, you'll need gobs of power. Efficiency and extension, prepare for a huge enclosure. Etc, etc. The reason the RSW subs have more punch is they are tuned to a much higher frequency (passive radiator and a port do the exact same thing in a slightly different way). The highest tuned SVS will be tuned lower than the lowest tuned RSW. You pretty much have to sacrifice some punch to get extension (unless you are dealing with massive arrays of drivers in an infinite baffle or huge bass horns) which is what the SVS do while the RSW don't. Also the cylinders are a little decieving. The RSW15 is ~100L enclosure. The 20-39 is ~120L enclosure and the 16-46 ~150L enlcosure.