GenII Shiva/Tempest FAQ

**Kevin Haskins** · **05-20-09, 08:14 PM**

I'm going to sticky this for information on the GenII Shiva-X, & Tempest-X. I'll update all parameters, cost, availability and technical details in this thread along with answer common questions. If you have questions, please read through this thread before firing off an email.

1.) What is the difference between the first generation Shiva/Tempest & the Gen II product?

History Lesson:

Answer: Actually, I should answer this by giving some of the history of the drivers. The Shiva, was the first product produced by a company called Adire Audio. It was a driver designed by Dan Wiggins & David Hyre back in the days when 10mm of x-max was BIG stroke. It was originally an overhung motor, with about 14mm of xmax, built on a stamped frame basket and built by Eminence as a high-value driver with a nice balance of the T/S parameters for both sealed & ported alignments. It literally was a product that changed the industry as it was the turning point for high-excursion subwoofers becoming main-stream and it set the standard for performance/$. Time rolled on and Adire Audio updated the basic Shiva a couple times, introduced the Tempest 15", and in the mean-time Dan & Dave created a new motor technology, XBL^2 which all of the Exodus Audio products currently use. The XBL^2 motor technology made it into many upscale Adire Audio products, but not the Shiva & Tempest.

Adire Audio officially went out of business in 2007. The loudspeaker business is a tough place to make a living but luckily, Dan Wiggins has continued on as an engineering consultant for a number of audio companies under Acoustic Development Inc. David, who contributed much of the basic FEA analysis for the work on the XBL^2 patent, continued in teaching and research at the University of Washington.

Exodus Audio was formed back before Adire was officially out of business. Exodus Audio is a brand created by Kevin Haskins (me) of DIYCable Inc. I've been friends with Dan since I started the business in 2001. After Adire Audio closed their doors, it seemed a shame that the Shiva & Tempest would die so we resurrected the products with some updated designs.

Today's Shiva & Tempest bear little resemblance to the original. Sure... the cone looks roughly the same. We still use a basic pressed treated paper cone and the appearance of the woofer is purposefully subdued. The entire concept for the Shiva & Tempest is high performance, but not high-cost. There is little money spent on exotic cosmetics, branding or features that don't contribute to the performance of the device. If you want a flashy car-audio sub with a brand name written all over the dust cap, you don't want a Shiva or Tempest.

The first Shiva/Tempest produced under the Exodus Audio brand name where designated Shiva-X & Tempest-X, in order to differentiate between them and the Adire Audio branded units. The 'X' versions featured XBL^2 motors, with significantly more x-max and capability than the original Shiva & Tempest designs.

The Generation II Shiva-X & Tempest-X, feature the following differences from the first Shiva-X & Tempest-X:

Improved CuAl Inductance Ring Optimization. The inductance rings are designed to keep the inductance constant with power & stroke. Different materials, of different thickness are used in different locations to keep inductance well-behaved at all signal levels. Most shorting rings are a simple copper or aluminum sleeve dropped in the gap and provide no help with changing inductance over stroke and with power. The shorting rings need different abilities at different locations based upon the physical layout of the transducer, and the power in the voice coil at that location. CuAl inductance optimization does that, simple sleeves in the gap do not.
Improved Suspension Linearity. We better optimized the Kms curve to be more linear with stroke. With all woofers, we aim to have x2-x3 the suspension stiffness at the 30% down point on the BL curve (xmax). Having the curve be symmetric, lowers non-linear distortion. Allowing the suspension to gradually stiffen, provides safety for the driver under overload conditions. A linear subwoofer is no good if you damage it easily. Our suspension design balances linearity, with safety in ways based upon years of design experience.

Tempest Kms (suspension curve):

Tempest/Shiva BL Curve:
Increased Voice Coil Size. We wanted to decrease the enclosure sizes for the next generation of product. Why? We have some larger subwoofers being released that now are more suitable for larger box sizes. In order to widen our appeal, we aimed to decrease the average size of enclosure needed for the Gen II product. To do that, we needed higher motor strength. As a bonus, we get slightly higher power handling.

I'll update this post with production parameters once I get inventory. This is just a little "teaser" and FAQ area for questions about the GenII Shiva-X & Tempest-X designs.

Kevin Haskins
Exodus Audio

**Kevin Haskins** · **05-20-09, 08:27 PM**

FAQ:

Question #2: What kind of enclosures do the Shiva-X & Tempest-X use?

That is beyond the scope of the FAQ. We will have updated application notes for the Generation II Shiva-X & Tempest-X once they are released.

Question #3: Is a Shiva-X, Tempest-X as good as the driver used in finished subwoofer from company "XYZ"?

Good question and a difficult one to answer. For one, I don't like to put down other companies. I also don't have access to every subwoofer on the planet so all I can really do is make generalizations. Generally, the Shiva-X or Tempest-X are going to be vastly superior to your typical OEM subwoofer. Why? I'm much more fussy about the design aspects than most engineers. I've made extremely high demands on the build-house, and I have one of the best transducer engineers on the planet. We understand these things better than most companies making subwoofers. That may sound like bragging (and it is a little), but we understand the fundamental things that make these things work better than most. I see little reason to save a dollar or two on design factors that improve performance. Many OEMs have very tight price point to hit. You don't spend money on things unless it is going to sell more product. You would think that would relate to performance, but it often doesn't. The Shiva & Tempest are no-frills products that just perform better than most subwoofers you can buy in their form-factor.

Note: Good final design depends on much more than just the transducer. Follow our application notes and you will get fantastic results. Ignore them, and the subwoofer may sound worse than the WalMart $100 cheapo sub.

Kevin Haskins
Exodus Audio

**Kevin Haskins** · **05-20-09, 08:42 PM**

FAQ

Question #4: Why are these subwoofers so expensive?

To some extent, quality cost money. The goal with our subwoofer lineup, especially the Shiva-X & Tempest-X was to make them high-value products. That means that for their price point, they reflect a very good buy. We saw little value in making another $100 subwoofer, that was marginally better than other products from other companies. We are techy nerds and it hurts me to design a pedestrian product.

The Shiva & Tempest-X use motors with lots of steel. Each transducer is in excess of 33lbs, most of that high-grade steel. We also pay licensing fees to use the XBL^2 motor technology. The shorting ring arrangement on these drivers is much more complex and costly to manufacture than a standard motor. We also specify very high tolerances and have high standards for glues and assembly & testing, higher standards than your typical product. It all adds up but we feel that the Shiva-X & Tempest-X strike a nice balance of performance for the dollar.

Kevin Haskins
Exodus Audio

**Kevin Haskins** · **05-20-09, 08:49 PM**

FAQ

Question #5: Why are these subwoofer so inexpensive?

I'm only partially joking in posting these two questions back to back. I actually get both questions on a regular basis. One man's Yugo is another man's Mercedes.

We do sell these products significantly cheaper than most of our competition. One of the reasons why is we sell direct. There is no Exodus Audio dealer network (there are International Representatives due to our inability to service those markets directly). I run on fairly tight margins because I don't have much overhead. I outsource the manufacturing, most of the engineering and anything else that I can outsource. I get boxes in the door, and ship them back out with a UPS label stuck in place. Operating like this allows me to work at margins others wouldn't consider. I directly support the product, I have a hand in engineering it, I write the documentation and I answer the phone when you have a question. Operating like this is about the most cost effective method that I know to design, manufacture and deliver a product to the end-consumer. There is little in the way of fat.

Kevin Haskins
Exodus Audio

**Pete B** · **11-17-09, 02:08 PM**

What type of voice coil former do these drivers have? Is it thermally conductive? Also would like to know about your other drivers, EX-6.5 for example.

Pete B.

**Kevin Haskins** · **11-17-09, 02:36 PM**

We use anodized aluminum formers from one of the best manufactures in the world for all of our drivers. They are expensive compared to some of the cheaper alternatives, but the former/voice coil is the wrong place to try and save money on a driver design. It takes the most thermal abuse and the tolerances have to be tight to prevent any chance of a rub. Heat dissipation in a subwoofer is a critical function and the VC/former is the area that has to handle the massive amounts of heat that we routinely pass through them.

We get VERY few thermal problems from systems in the field. I can count on one hand how many thermal failures I've seen in the last four years and two of them I was responsible for while abuse testing drivers. If you take into account that almost all of our Maelstrom customers are using >2000W of pro-sound amplifiers, that record is almost unbelievable. I routinely recommend 2000-3000W amplifiers for customers using the Maelstrom-18" & 21". In fact, I tell customers that they don't need to worry about maximum power.

Kevin Haskins
Exodus Audio

**Pete B** · **11-18-09, 05:58 PM**

Thanks Kevin that is good to know.

I see the rated Xmax as 26 mm, what is the rated Xmech or is it roughly the same as Xmax?

I do understand that it takes a lot of power to get these drivers to Xmax.

Pete B.

**Kevin Haskins** · **11-18-09, 06:45 PM**

Quote:

Pete B wrote:

Thanks Kevin that is good to know.

I see the rated Xmax as 26 mm, what is the rated Xmech or is it roughly the same as Xmax?

I do understand that it takes a lot of power to get these drivers to Xmax.

Pete B.

No....good design requires that you have significantly more mechanical clearance than motor to hit it. The drivers all soft-bottom, which means the suspension runs out before the former hits the back-plate. The mechanical clearance is around 35-37mm one way and I'm unable to get enough power into them in free-air to hit that. The suspension locks up well before that point.

The Xmax, is nothing more than the point on a curve where the BL is 30% down in relation to the resting position. We tend to design the suspension so that it is tightening up and the stiffness of the suspension is x2-x3 the stiffness as it is as rest when you pass xmax. That way you have two forces that are occurring simultaneously, the motor force falling off, and the suspension getting stiffer so the amount of power necessary to move the cone out at the limits is exponentially higher than what it takes at rest. Following that design mantra, makes it very difficult to physically damage the driver.

It takes a lot of power to get ANY subwoofer to 26mm one-way. It is the nature of the beast.... if you design a driver for a given bandwidth, and a given box design, the efficiency pops out the other end of that equation. Neither I nor any other company can change that relationship unless you go to a non-conventional enclosure like a horn. Then you have another set of tradeoffs so there is no free lunch.

**Pete B** · **11-18-09, 08:22 PM**

I see, I would not have expected it to be the same but there was no mention of the spec.

I'll take Xmech to be about 36 mm one way.

You say the suspension locks up, so is Xsus lower than the 36mm figure? Do you have a value for it?

I actually suggested the 70% down point for Xmax years ago on the old Bass List. Xmax was usually spec'd as the usual theoretically linear value back in those days when the 1259 was the Xmax king.

I also like a figure that I came up with and call Xmax50 for the 50% down point.

I have also pointed out that if you don't have the power to drive a woofer to Xmax or even 30% beyond, then there is a more optimal driver for the particular power level/amp in question.

**Kevin Haskins** · **11-18-09, 09:23 PM**

Quote:

You say the suspension locks up, so is Xsus lower than the 36mm figure? Do you have a value for it?

I don't have an exact figure for where it locks up. I suppose I could pick a number but it isn't easy to come up with a meaningful one. The Klippel Cms just skyrockets as you get past Xmax so it is pretty hard to pick a hard and fast number from the Klippel. If you run the driver in free-air you can drive it to that point, but it is difficult to get an exact measurement. Since coils are never perfectly centered, it is an academic debate. What I tell people.... is you get around two inches of P-P usable output. Once you put it in a box, and look at the power levels required for driving it past xmax, you are quickly into extreme levels. I focus more on the linearity between minus/plus 20mm because that is where the driver is primarily used. Once you push them past xmax, you are well into gross levels of distortion.

The shape of the BL curve with XBL^2 drivers causes the fall-off to often be steeper than in something like an overhung. Once again, on a graph where the curve is almost straight up/down, it becomes difficult to pick an actual point that doesn't vary from driver to driver in a production run.

Quote:

I have also pointed out that if you don't have the power to drive a woofer to Xmax or even 30% beyond, then there is a more optimal driver for the particular power level/amp in question.

I'd agree in the extreme examples. But... if the driver doesn't cost any more than the less capable driver, I'd much rather had a device that was completely linear over +/- 20mm, than one that was only linear over +/- 12mm. There is no tradeoff for linearity other than good engineering and to a degree, cost associated with designing it right. For xmax, you have to pay for the steel, and the cost associated for the bigger motor.

Kevin Haskins
Exodus Audio

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