Sonosub vs. SVS (1 Viewer)

I know this has probably been asked here beofre, but I am looking for some specific info to my situation:
I am interested in building a Sonosub using the Shiva and have avidly followed many of the threads here on the subject. I want o build it partly for the fun of the prject, but moslty to add some good bass to my Home Theater system.
I am in Canada and was pricing out all the stuff required. I already have approx 3.5 feet of 20" Sonotube which is what I want to use. Looking at the cost of the sub and all the the other supplies it is probably goign to run me $300US (excluding Amp), plus I don't own any tools so will have to buy some of them also.
To get to the point...
Is a 20" tube-based Sonosub with Shiva subwoofer likely to significantly outperform a the $400 SVS subwoofer? I was browsing their site and noticed there was one for $400 that is tuned to 25Hz and is 31" tall.
If I am to spend $300 on driver and supplies ot build a sub based on the SVS design I would want it to outperform something I can buy off the shelf for only $100 more.
I am pretty green at this and don't know where to start designing my sub dimensions (as I didn't even know what type of sub design to pick from the LspCAD, let alone know how to use it.)
I am confident in my abilities to do the wood working involved, and would enjoy the project itself, I just want to know what difference I can expect.
Is the Shiva driver signifcantly better than the dirver used in the SVS systems?

Robin, I'm starting my sonosubs next week and would also like to know how the SVS compares to a 'DIY clone' using the Shiva. I think that if the Shiva was significantly better than the SVS driver, SVS would be using the Shiva.
Harry.
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"You're too old fat man, and your tits are too big, get the f**k off my porch!"

This is going to open up a huge can of worms. Let me start off by saying I use a sealed shiva.
Either system will give you bass beyond your wildest dreams. It all really depends on wether or not you want to build it yourself. I would say that a Sono-Shiva would give slightly better results then the low end SVS. But it is all relative. I can say that my sealed Shiva gives all the bass I currently need for myself. If I get a bigger room things might change.
To end all arguments quickly lets just say that they both will give astonishing house shaking bass you just have to decide which route you want to go. To me my sub sounds that much better just knowing I made it.

This has been discussed before, and there's no argument or can of worms,really. The specs on the SVS driver are proprietary, so an attempt to compare to Shiva would be fact-less at best, and there's no reason to assume that SVS would use the Shiva if it were "better", as there are other reasons to design your own driver for your own commercial product. What can safely be deduced is that the SVS driver is excellent.
Given the fairly well-known performance envelope of the Shiva, it's unlikely that one could noticeably exceed the performance of an SVS with just one. To do that, you'd be better off going with a Tempest, which has more displacement
than a 12", and could be right at home in your 7 ft.^3 tube.

Thanks for the input.
Jack, it sounds like upgrade fever...
For just $30 more I can buy the tempest, but it will also require more amp to drive it well, right?
Plus, a 15" driver in a 20" tube, is that okay? My port would have ot go on the other endcap then right? I won't have room for 15" driver, 4" port and speaker bidning posts on my 20" dia endcap. My preference was to "hide" all of that at the bottom.
Is there anyone who has an SVS and a Shiva based sonosub who can make some A-B compares?
I am new to this game and it will be my first "homemade" project.

If I go with a port on the top, can I put a grill cover over it? I have kids who for sure will drop something in there!
Also, do Adire have scratch and dent Tempests? I wan't to keep my costs down if I can, as I have to ship to Canada.
Will there really be a big difference between the Tempest and Shiva? I have NO subwoofer right now, so I figured going to a Shiva-based config would be a good addition that wouldn't break the bank. Esp. since its my first DIYer.
Thanks

Robin,
I'm about to try one of these also. I'm going to make mine sealed (just to keep it simple and idiot proof) with wide sonotube. Although adire has a wealth of info on the shiva and tempest, I was unable to figure out the tradeoffs between the two for a medium sized sealed enclosure, so I just asked them. I'll let you know what they say.
Brian

Hey Robin.... when you get your parts and such shipped to you... could you let me know how much extra you had to pay to get the stuff across the border?
Seems we're fairly close together... and I have a sealed shiva design in the back of my head I'm hoping to get to soon.
Thanks.

Hey Kevin,
Did you know about Q-Components on Colby, up off of Northfield Dr?
They are a speaker supplier and have GOOD prices on binding post cups, ports, grills and such. I plan on getting most of my other stuff there.
The only thing I'll need to mail order is the Shiva or Tempest itself. And maybe an amp, depending on what I go with.
Brian, I don't know if anyone has more solid feedback but is a sonosub going to work as a sealed enclosure? My gut reaction would be "no" but I am new to this game, I thought for sealed subs you needed an even more rigid and braced design than with a ported sub, but I could be wrong. I'd check it with some of the gurus here before proceeding. Let me know what they say about the Tempest - Shiva differences.

>>>Is a 20" tube-based Sonosub with Shiva subwoofer likely to significantly outperform a the $400 SVS subwoofer? I was browsing their site and noticed there was one for $400 that is tuned to 25Hz and is 31" tall.>This has been discussed before, and there's no argument or can of worms,really. The specs on the SVS driver are proprietary, so an attempt to compare to Shiva would be fact-less at best, and there's no reason to assume that SVS would use the Shiva if it were "better", as there are other reasons to design your own driver for your own commercial product. What can safely be deduced is that the SVS driver is excellent.
Given the fairly well-known performance envelope of the Shiva, it's unlikely that one could noticeably exceed the performance of an SVS with just one. To do that, you'd be better off going with a Tempest, which has more displacement
than a 12", and could be right at home in your 7 ft.^3 tube.>>Will there really be a big difference between the Tempest and Shiva? I have NO subwoofer right now, so I figured going to a Shiva-based config would be a good addition that wouldn't break the bank. Esp. since its my first DIYer.

If you are deadset to go with a sealed design, you won't be disappointed with a 7 ft^3 enclosure with a Tempest. Your F3 winds up around 37Hz (you don't get the super low F3 unless you go ported or use passive radiators). The sub should be "tight" due to really low group delay (under 8ms at 20Hz and less at higher frequencies), the cone excursion down to 30Hz stays under the Xmax for the driver. I do recommend 3.5 pounds of polyfill to be stuffed in the enclosure if you go the sealed route.
Just realize you are trading off low end response when you go the sealed sub route.
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PatCave ; HT Pix ; Gear ; Sunosub I + III ; DVDs ; Link Removed

Thanks Patrick. That 37 Hz F3 is a little depressing, but at least it will continue to roll off slow from there. May have to put a boost in like Hsu. Would a Shiva in 7 cu feet sealed also have an f3 of 37 Hz or would it be even higher ?

Brian, you should download the LspCAD from the Adire Audio site and play with the number yourself. Once you get the hang of it, it's quite useful.
Using the Shiva in a sealed 7ft^3 enclosure, your F3 rises to 43Hz, and your cone excursion goes up (assuming 200W amp) close to the Xmax around 30Hz, group delay is fine (just above 5ms at 30Hz and less above 30Hz).
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PatCave ; HT Pix ; Gear ; Sunosub I + III ; DVDs ; Link Removed

This thread details TerryC's 4ft^3 Tempest design. As you can see, its high power handling and "swept volume" allow it to respond pretty well to a low-bass boost, to extend the in-room f3 very low.

I find it interesting that by checking the "Voice Coil Heating" box, that gets you to most of the lowered F3 value in-room response. It's all relative, isn't it.
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PatCave ; HT Pix ; Gear ; Sunosub I + III ; DVDs ; Link Removed

Yeah, VC heating seems to have a much larger effect than the other ones. I guess it makes sense, as the VC will heat up even before it excurses out of the gap. When using the crossover (as I assume everyone will),though, the cumulative effect of all three on the f3 seems to be less than 2 db. I deduce from this that VC heating is having more of an effect on the upper range of the driver, beyond the usual 80Hz crossover. This is also what the free-air response graph shows.
I don't really understand these non-linearities, apparently, as this seems counter-intuitive to me.