Hi Dave. Our Shiva/Tempest line is very efficient. But I think you are refering to our Brahma line. You are right that they are a little less efficient than other drivers. But we designed them this way. Power is cheap while real estate in vehicles usually isn't. We designed the Brahma for a small box, and as per Hoffman's Iron Law pointed out by Rob, to still get decent low frequency response, efficiency must suffer. Since power is cheap, we didn't feel it was a problem.

We do have one advantage with efficiency over most other drivers on the market. With our XBL^2 motor, efficiency stays the same throughout it's excursion. With other drivers, as they move efficiency drops. And in many cases it drops below our efficiency very quickly. This means that they only have a higher efficiency at lower excursions.


Every type of cone material out there has advantages and disadvantages. When you engineer a speaker, you have to decide which one would work best for the design. We chose paper because it had the proper stiffness and weight. Our paper cones are probably the toughest cones out there. We've had a 300 lb. guy standing on a cone/former upside down and jump on it. The former folded, but the cone didn't budge.

Maybe you could explain why you think paper is a poor choice for cones?

Actually foam is superior to rubber for a surround on subwoofers. With treatments available today, foam surrounds last much longer. Rubber has a problem with stiffening up over time. This greatly effects it's performance, and therefore doesn't last very long. Foam also also does better from a performance standpoint. Rubber tends to suck-in, and to prevent this you have to make the surround thicker. This adds uneeded weight, and stiffness. Foam doesn't have this problem.




A subwoofer is made up of a great deal more parts than just a cone and surround. In fact, a cone and surround add very little to the "sound" of the driver. That is usually obtained from the motor design. After all, how much effect does the hood of a car have on acceleration?

I'm very glad you say that. It is too bad you have judged our drivers based on a couple material choices. Because I really think you are missing out. Our Brahma was the vehicle that introduced our XBL^2 motor. This motor keeps the BL flat throughout the excursion of the driver. This means that it will have less distortion at any output level over a standard motored driver, which gives it more "accurate sound reproduction". Check these two links for more technical info on our XBL^2 motor:
Overview
Details

Steven Kephart
Adire Audio

 

Cool info guys and I appreciate it. I think maybe I have prejudged the bramas incorrectly. But I did say that I haven't heard them. I have heard a plethera (sp) of bad sounding woofers using paper cones. As a matter of fact I can't say I've ever heard a paper cone woofer that I have liked. The closest was a home sub which was servo controlled (velodyne) several years ago. But Steve and RTH are correct that the motor is more important in a sub.

I still beg to differ about the L7 in a small box and I was referring to the 10" in a cubic foot or less and not the 15" Let me explain it this way and maybe RTH can understand. Typically as a GENERAL rule you would put a woofer with a "Q" of .4 or higher in a sealed box and .4 or less in a ported box BUT does that mean you can't bend the rules a bit and end up with positive results? Yes you can if you know what you are doing. Specs are like guidelines but the end result is what counts. BTW here are the specs:

Recommended Enclosures
- Moderate Efficiency -
Model Compact SQ (.707 alignment)
S10L7 1.0 cu.ft. Power Handling =600W


Keep up the good info guys because I surely don't know everything.

And just because I haven't heard a paper cone woofer that I like doesn't mean that they don't exist. And If it sounds good to you then buy it. We can only provide recommendations but you should go with what sounds good to you. You ears should be your guide to making final determinations. If you are like me you might need a lot of time listening before you find something that sounds just right so be patient.

 

Paper in most cases, but not all, is inefficent because of greater losses compared with other materials. However it is not the only determining factor of efficiency and as I have stated it is not always the case. Some paper drivers are coated and sealed decreasing losses.

I like this "Law" and I'm glad you brought it up. The 10" L7 has Low frequency extension in a small box BUT is FAR from efficient. I'm exaggerating here but it seems to take several hundred watts just to get the thing to move in the recommended tightly sealed box.

As stated earlier cone material CAN be a factor in efficiency and definitely in clarity. Whatever material is used in cone matierial it should be stiff. No confusion there.

I guess I think of paper coned woofers like front drive drag cars. You can make it work but fairly well but it's not an ideal way to go. And this has been the case for decades. Even wood is being replaced with composite in the lumber yards for some applications. Wood and paper is cheap which is good for the manufacturer but not good for me. I want something better which is not too much to ask.

 

I haven't heard some of this before but I'm not sure I agree. There seems to be some truth to what you are saying but I'm not ready to say foam is better. In the past foam has also been associated with losses and butyl rubber seemed to be the material of choice. The treatments you speak of may change all that. Kinda like sealing paper cones and now sealing foam to prevent losses. It still seems like a kluge (sp) to me though. Just develop a material that doesn't have these issues. I know I am asking for a lot here but I do have high standards.

 

Tekprodave posted:
If they aren't accurate, then you're correct. If the specs ARE accurate, though, they can mean quite a bit. Specs are just a numerical way of describing the driver. Provided with a proper set of complete specs, you can get a really good idea of how a given driver will perform in a desired application. But as you caution, many times they cannot be relied upon because the accuracy is suspect.

Then the specs are incomplete or inaccurate. I've yet to find a driver that measured flat, had useful T/S parameters (for the given application), and had low THD and IMD that couldn't sound good. If it sounds bad (I've heard Dynaudio 17W75s sound like crap before, and those drivers are DEFINITELY not bad), it's often the implementation that is the problem, not the driver.

Since you have experience with XO design, you know that the largest impact on sound - by a long shot - is the crossover. Take the best drivers in the world, give them a crappy XO, and it'll sound terrible (witness a large percentage of the high end audio setups at CES each year). On the converse, though, you can take relatively pedestrian/low end drivers, add a good XO/system design around them, and end up with a great sounding speaker (witness Dunlavy, Genesis,etc).

Then perhaps you're not up to speed on modern technologies? If anything, foam surrounds and paper cones tend to have the highest strength/mass ratio, meaning you need the least amount of mass to get a given rigidity. And as you must know (basing upon your experience) efficiency is strictly BL and moving mass. If anything, foam and paper are used a LOT in pro-sound because it is a way to keep moving mass down.

Additionally, foam has some SERIOUS advantages over rubber, so much so that most companies use foam (witness the JL Audio W7 - all foam surrounds - as one prime example). Foam is:

- Lighter for a given compliance
- More linear in terms of motion-versus-compliance
- More linear in terms of temperature-versus-compliance
- Thicker for a given mass (reduces issues of suckback)
- Easier to bond to a variety of cone materials
- Easier to form with high precision

In short, there's really only one thing rubber may have an advantage over foam, and that's in longevity. However, modern foams are treated with UV and rot inhibitors, and will have 10+ year lifespans without a problem (we've had foam surround drivers in tropical installs for nearly 10 years now without a problem). So even this "advantage" becomes somewhat moot (especially when one considers that rubbers typically dry out and stiffen as they age, making the driver unusable as well).

As far as the rigidity of paper goes, here's a picture for you:


That's me (300 pounds) standing on the former of a Brahma cone. Full weight supported by the cone itself, and it doesn't buckle. The surround is curled up on the bottom, but the cone is intact. This from a 100 gram cone. I'd say that's pretty stiff for such a light weight...

Then by all means don't listen to JBL, or Vifa, or Peerless, or a host of other companies. Most of your top drivers (like the Scan Speak Revelators, for instance) use paper (or paper/poly blended) cones. Why? Inherent rigidity AND internal damping.

Except that internal losses aren't really an issue. For smooth cone response, yes. Internal losses will affect cone cry, which means it will SMOOTH the frequency response. But from an efficiency standpoint, cone material has ZERO impact.

Efficiency is strictly moving mass and BL. Understanding this, and knowing that paper is stiffer for a given mass than metals or poly, you typically can have HIGHER efficiency with a paper-based cone, because you need less mass for a given rigidity.

Doubt it? Take a look at ANY pro-sound driver. That's an application where efficiency is critical. You'll find paper used almost exclusively. The light weight you can get from paper, combined with the internal damping, means you get higher efficiency, and a wider usable bandwidth (less high end breakup issue). And if you know the markets, you know that for every dollar spent in car audio, there's 20 spent in pro-sound. Pro-sound is a major market, and materials research is crucial. Paper is used because it is flat-out superior.

Yes, confusion there... Cone material will not affect efficiency, unless you factor in the required mass needed for a given stiffness.

It will definitely affect clarity, but that's one of paper's strength (as well as poly). Internal damping is high so that breakup modes are reduced.

I've worked with ultra-stiff cones before (the Seas Excel woofers with the magnesium cones). I'd rather work with a pedestrian Peerless CSX poly cone before I do the Seas again - something about 18+ dB breakup modes that make them really difficult to tame, especially from a spectral contamination standpoint...

Then when you find something better, you have a built-in market. But don't think it's been tried and is tried all the time. It sounds like you had a bad experience with paper once and automatically blamed it on the material, rather than the implementation. Literally millions of drivers roll out every week with paper cones, and not because of price.

ScanSpeak's Revelator woofers, for instance. The 7" paper cone units, are considered by a majority of professional loudspeaker engineers (myself included) as one of the best drivers in the world. It's $224 for the woofer, and they use a paper cone. ScanSpeak doesn't doggedly stick to one cone material because of tradition or cost - they have carbon fiber, Kevlar, poly, and other cone materials represented as well. But when it came to the Revelators, they chose paper, and with good reason: light weight (good efficiency), high internal damping (smooth frequency response), stiff (good pistonic action in the bottom end).

I'd suggest doing a bit of research into the foam and rubber surrounds of the last 10 years, and I think you'll quickly change your mind. There's a reason foam surrounds are so pervasive, and it's not cost (in fact, foam surrounds are often MORE expensive than an equivalent butyl rubber surround) - the superior performance outweighs the extra cost.

Dan Wiggins
Adire Audio

 

Dan Wiggins
Adire Audio



Thanks for taking the time to provide this info. I can't say I agree with everything but you have given me a lot to chew on and you seem to know what you are taking about. I guess I can't rule out materials in sub designs I just have to listen and consider the application. I went with a 10" Kicker L7 for my car sub because it does a good job in a cubic foot box. I was looking for low bass extension (25hz or less), clarity, accuracy, etc., because of the music I listen to. So the big question.........What driver in Adire's line would do well in this application?

Dave

 

From our line, in a 10" form factor, the Koda 10 would be a good option.

Dan Wiggins
Adire Audio

 

Thanks Steven and Dan, I really appreciate you taking time out to help straighten this out.....


I am sorry to take this whole thing so far off topic. But i still say that the Square solos are not really a small box sub. Dave recommends a 1 cube box for a 10, and that might be just fine. I just wouldn't consider a 1 cube box for a ten very small, unless you are talking about a 1 cube ported box for that ten. I guess i consider a small box for a ten in the 1/2 cube area. I have only heard the 12" solo, but i have heard it in a plethora of boxes and i can't say that i liked the sound in anything relativly small, I didn't think it sounded that good in 1.5 cubes, and worse in the smaller boxes.....

I guess that this whole thing could have been avoided if i would have noted that i consider a small box for a ten to be under 1/2 cube and under 1 cube for a 12..... I believe these are close to the recommendations for most subs that claim to be "small box".

 

Ahhh. I see the misunderstanding. So no big deal then. Sorry if I seemed rude at any time. I agree the 12 is not as good in the context you are bringing. It's funny how you are talking about some REALLY small boxes for these woofers. It doesn't even seem like you could physically fit a 10" woofer in a .3cu ft box.

 

I'll check into it. I have three other cars that lack the boom boom. Is there an Adire dealer in Sac? Disregard this question. I've got the info I need. I'm curious though, why wouldn't you recommend the brama? They are closer to the L7 that I have now.

 

I actually have my Brahma 10 in a .36 cubic foot enclosure. It used to be in a .5 cube which gave me .36 after displacement. But now I just inverse mount it. You can see pictures of it here.

Steven Kephart
Adire Audio

 

Probably because that enclosure is a little large for the B10. You are getting close to ported size at 1 cubic feet. The Koda 10 is designed for larger enclosures, and would work best in your situation.

Steven Kephart
Adire Audio

 

That's no biggie. I can just get or build a different box.

I'd have to anyway because the box I'm using has a big square hole in it.

 

He he. And I thought I was crazy!! Just kidding. Teg's are cool. I've owned 4 of them. A '91 4-dr, '92 GSR, '93 GSR, and a '96 GSR. I liked the 2nd gens the best. They are fun to drive but I got into drag racing and sold them in favor of LT1 powered cars.

I can't say I'm crazy about inverse mounting because it defeats the purpose of saving space. But it would look cool if you mounted 2 inversly to the same box.

 

Havent read the entire post but about 1.5 week ago Ls1 Rulz recommended a 10 in Type S over my Blown JL 10W3 D2. I listen to him cuz I trust his judgement. He never steered me wrong. Well, I can honestly say the Type S sounds just as good as my 10W3 did in the same MTX Stealth box (BUT at a FRACTION of the price). I am Very happy with it.

By the way, its only been a week and a half but I am pushing it with a 400-500 RMS Watt Rockford Fosgate Amplifer...so you can take that for what its worth..

Good Luck in you choice.
Thx,
Claude