Phoenix Gold Cyclone - most unique subwoofer - dissection pics

[geolemon 10+ year member]

Well, some people seemed to express interest in the Cyclone...

So I decided to disassemble mine, documenting what it is, and how it works.

//content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gifhttp://www.betteraudio.com/geolemon/cycloneinside //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

The goal of that page is to explain more clearly "how they work".

I think the pictures, the disassembly, should help you understand it, if you are a bit unclear on what this thing is, and/or how it operates. //content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif

Here's a little head start:

What is it?

It is a rotary, servo-motor subwoofer. It consists of a flat panel, bisected by the output shaft of a DC servo motor.

A DC servo motor spins when fed DC electricity (DC, current moves in one direction). When fed AC electricity, such as the output of an audio amplifier (musical signal is alternating current), it will crank that shaft back and forth, waving the panel.

It uses two curved ramps inside a large cylinder to redirect the air being pushed by the waving panel in and out each end of the cylinder, allowing the Cyclone to stimulate the air just like a traditional subwoofer.

There has never been another rotary servo subwoofer that's been on the market, it is unique.

When was it made?

It was manufactured by Phoenix Gold beginning in the early/mid 90's, and sold until a few years ago when it was discontinued.

It's very Servo-Drive-like big brother, the Vortex (a rotary-to-linear motion converter enabled dual-15" cone monster), never made it to production.

Why would I want one?

There are many reasons.

One big one is efficiency:

Traditional voice-coil motors are about 1% efficient, while a servo-motor is about 10% efficient. So, 300 watts to this subwoofer is the equivalent of feeding a monster sub 3000 watts. Your electrical system is breathing easier already.

This also has the displacement of about three typical midgrade 12" subwoofers.

Another reason is sound quality:

If you've been following the forums the past year, you know the focus that's been put on producing subs that have "broad BL curves", so that as the cone's excursion level changes, BL remains constant... if BL does not remain constant, distortions will occur.

By nature, a servo motor can rotate a full 360 degrees without it's BL value even flickering. It has a literally infinitely flat BL curve.

Who made it?

While it was manufactured by Phoenix Gold, but it was co-designed by Tom Danley of Servo-Drive. Tom literally owns every patent that can be had on the concept of producing servo-motor powered loudspeakers... which might answer the question "why aren't there more loudspeakers like these?" //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Tom used two of these in his own home reference system, for years.

Click to read more...

 

[awalbert88 10+ year member]

Well, some people seemed to express interest in the Cyclone...So I decided to disassemble mine, documenting what it is, and how it works.

//content.invisioncic.com/y282845/emoticons/scared.gif.f134e57c6c93ccd0f15aa5ac32c7d4a0.gif

......

 

[mattj 5,000+ posts]

after you are done playing with it, can i have it?

//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[ws140 10+ year member]

so how does it sound compared to a regular subwoofer?

 

[geolemon 10+ year member]

It sounds just like a regular subwoofer... albeit with a shockingly low Fs (10Hz! //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif).

It is the original super sub, if you will...

Literally infinitely-flat BL curve (inherent in servo-motors) yields great sound quality - designer (and owner of all servo loudspeaker technology patents //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif) Tom Danley used two of them in his own high-end home reference system for years.

High displacement capabilities, coupled with it's amazing efficiency also happens to give it really remarkable SPL capabilities, even in sealed enclosures.

 

[kingpin_jeffie 10+ year member]

Jmac, arent you getting one of these?

 

[geolemon 10+ year member]

Here's a great link with more information, from Phoenix Gold themselves:

http://www.phoenixgold.com/webfaq/cyclone.htm

The most noteworthy thing on that page is the paragraph on "The Amp", and the spec sheet at the bottom.

Missing from that spec sheet are the T/S specs, here's the basics:

Qts = 0.49

Vas = 838 l

Fs = 10 Hz

//content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif

 

[LoneRanger 10+ year member]

There have to be some drawbacks to this thing, or we'd all be using them by now.

I have absolute minimal understanding on how this thing works, much less what kind of enclosures it does well in......however I'd be very interested in finding out.

There are also a few statements on PG's website that seem sort of odd to me:

THE CONCEPT: The goal is sound quality. By that we mean sub-bass that sounds like it's coming from in front of the windshield; blends seamlessly with tight, fast mid-bass; and effortlessly reaches high volume levels.

Altho this piece of equipment may have a broader BL curve and 10 times the efficiency, it's still not going to sound any more "seamless" than a regular driver, nor will the imaging be better. Both servo-drive and standard voice coil woofers basically do the same thing, to the best of my knowledge: Use a radiator to move air. The shape/size/color of the moving mass makes little difference in the actual sound being produced.

GETTING THERE: The Cyclone is best thought of as a low frequency air pump. It is most at home when used with dedicated 6.5" to 8" mid-bass drivers. How the Cyclone interacts and blends with the mid-bass drivers is the key to great sound quality.

 

MID-BASS DRIVERS: Locate the mid-bass drivers in the front of the listening area; try the doors, kickpanel, etc. We strongly recommend having an enclosure for the mid-bass drivers and giving them all the power they can handle. In a Cyclone system, the mid-bass drivers give us our impression of SPL as well as the location of bass sounds within the listening environment

AH HAH! THERE'S THE RUB!

The frequency response must be severely limited in the upper octaves.....now we're cooking with gas!

THE BOX: Many experiments have concluded that the best box is a sealed box that shows the Cyclone 2.0 to 2.5 cu.ft. Remember that the Cyclone displaces .5 cu.ft. by itself. If the Cyclone will be inside the box, make it 2.5 to 3.0 cu.ft. If the motor is out of the box, make it 2.0 to 2.5 cu.ft. For rock, rap, or most other popular music, use the smaller size box. For the ultimate in smoothness and transient response, use the larger size box. You can mount the Cyclone at any angle either in the box or with the motor exposed. Build the box as strong as possible using MDF or better material. Line the box with a few inches of polyfil or other acoustical material

How does it perform in a ported box? Why even no mention of ported boxes?

THE AMP: We can't stress this enough, the Cyclone doesn't need a ton of power to do its job. That's one of the best things about it. It only needs about 150 watts continuous (300 peak) for full excursion @ 20Hz. Choose an amplifier with about 300 to 600 watts rated power bridged @ 4 ohms (remember that the Cyclone is an 8-ohm driver)

Have/Can the companies with the license on this servo-sub technology create one that will move more with more power, or is there a fininite limitation on the amount of effective excursion?

THE CROSSOVER: Use only active crossovers. Never use passive crossovers with the Cyclone. Use a steep (minimum 18dB per octave) crossover between the mid-bass drivers and Cyclone. The crossover point should be no higher than 60Hz. You may even go as low as 50Hz. The idea is to make it impossible to tell where the Cyclone is physically located. The only way to do this is to keep frequencies that can be localized (above 50 - 60Hz) out of the Cyclone.

Are they telling us not to let it play those frequencies because they're "directional" or because this device can't play them worth a ****? I know that sounds accusatory, but I've never heard or seen one of these things before, and I'm quite skeptical.

The bottom line here is this: The cyclone wasn't that expensive, nor was it extremely hard to come by, but for some reason it's not still around. Is this a product of the limited interest in such a strange device (hence people's resistence to change) or is this because of the limitations of the driver itself? Basically, if it were so ****ed good, why isn't it still around, and why can't I find one to play with?

 

[geolemon 10+ year member]

There have to be some drawbacks to this thing, or we'd all be using them by now.

Great question...

Every loudspeaker has drawbacks, compromises, depending on it's intended use, so I wouldn't worry so much about that, as a potential answer to the question of "why don't we see more of these"

... midranges have drawbacks in the scope of using them for low bass production, and subwoofers have drawbacks that make them inherently poor tweeters. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif.

There's a much simpler answer... or rather, a bunch of reasons.

Tom Danley of ServoDrive literally owns all the patents to the technology.

As such, he is literally the only one who can manufacture loudspeakers using servo motors, and he obviously could license the technology as well... but ALL efforts to build a servo-motor loudspeaker literally must go through Tom Danley. He has full and legally binding "yea" or "nay" power, and have no doubt that "yea" comes with a very large technology licensing fee.

Then, there's the cost of the drivers themselves, and the marketing aspect of it.

These motors themselves typically cost more than an entire large low-frequency driver, so when you have to budget in the cost of the motor, and the cost of the licensing fee, before you even get to the fabrication and manufacture of all the other necessary costs, it's easy to see you aren't talking about an inexpensive driver...

Which makes it all the more difficult to market - after all, you would expect your audience to be those audiophiles and pro-sound professionals who can understand and realize the potential of this new loudspeaker...

Unfortunately, these are also typically people who are already experts in traditional loudspeaker technology, who may rather select something that's already familiar to them, whose limits and handling they can predict and understand.

Anyone remember when the obviously superior technology of fuel injection came around? More power, less maintenance, better reliability, better emissions... it was a winner on all fronts. But a great many mechanics who were profiting on maintenance of carburators, and who invested a large amount of education on understanding the ins and outs and how to optimize performance with carburators largely rejected the technology. You'll still see some die-hard musclecar mechanics out there who will argue that the less-expensive carburation is a better choice.

Much like carburation, as mentioned above, the costs of a traditional loudspeaker are much less expensive, requiring less expensive parts, and less custom parts tooling. There are inexpensive pre-fab stamped and cast baskets, magnets, cones, surrounds, spiders available for the traditional loudspeaker industry - this industry doesn't even exist, for servo technology.

So while I think the biggest thing holding the technology back is that one man, Tom Danley owns all the patents - a legal monopoly, if you will - I think there are many non-peformance-related issues preventing any mainstream explosion of servo technology for bass drivers. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

I have absolute minimal understanding on how this thing works, much less what kind of enclosures it does well in......however I'd be very interested in finding out.

The end result is that it performs exactly like a traditional subwoofer, in that it causes sound pressure fluctuations....Therefore, it can be used in any type of enclosure application that a traditional subwoofer can be used in...

Subject to the same constraints that make a traditional subwoofer a "better fit" in a sealed or ported application (or 4th vs. 6th order bandpass, or aperiodic, etc.). //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

This particular sub leans a bit to the "sealed enclosure" side.

Tom Danley's ServoDrive products (such as the ContraBass and the BassTech7) seem to lean more to the ported side, they use passive radiators in their cabinets.

There are also a few statements on PG's website that seem sort of odd to me:
Altho this piece of equipment may have a broader BL curve and 10 times the efficiency, it's still not going to sound any more "seamless" than a regular driver, nor will the imaging be better. Both servo-drive and standard voice coil woofers basically do the same thing, to the best of my knowledge: Use a radiator to move air. The shape/size/color of the moving mass makes little difference in the actual sound being produced.

Sure... most of that is purely "install".But it is cleaner sounding than a typical subwoofer, largely due to that "infinitely flat" BL curve, which is inherent in servo motors.

That reduces distortion, meaning the subwoofer plays the primary tones it is being fed more clearly, with less higher-frequency harmonics coming off the thing... common with traditional subs, particularly those with parabolic BL curves.

Play a 20Hz tone on your subwoofer. You aren't supposed to hear that... what you do hear is largely harmonics, that are definitely not 20 Hz.

These harmonics are distortion, and they can "give away" the location of the subwoofer.. not because the 55Hz real note being played sounds like it's coming from behind you, but because the 110Hz and 220Hz harmonics (and other distortions) are coming from behind you. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

GETTING THERE: The Cyclone is best thought of as a low frequency air pump. It is most at home when used with dedicated 6.5" to 8" mid-bass drivers. How the Cyclone interacts and blends with the mid-bass drivers is the key to great sound quality. 

MID-BASS DRIVERS: Locate the mid-bass drivers in the front of the listening area; try the doors, kickpanel, etc. We strongly recommend having an enclosure for the mid-bass drivers and giving them all the power they can handle. In a Cyclone system, the mid-bass drivers give us our impression of SPL as well as the location of bass sounds within the listening environment

AH HAH! THERE'S THE RUB!

The frequency response must be severely limited in the upper octaves.....now we're cooking with gas!

All they are saying here is what all audiophiles say about any SQ oriented subwoofer system in a car...

You want the bass to sound like it's coming from up front, you need good midbass drivers up front to reach as low as possible, with good output levels, so that you can turn the subwoofer (whatever subwoofer that is) crossover in the back down as low as you can...

Because the human ear is less capable of locating the source of sound, the lower in frequency it gets.

I've never used the Cyclone with any particular considerations made to it... including crossover settings... I've usually played with it (in my car, and other's who've borrowed or demoed it) with the crossover set to a pretty typical 75Hz-80Hz, 12dB/octave. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

For sure, it's limited, in the upper octaves, in that this particular driver can't do midrange... but that's hardly a limitation given it's intended use, as a subwoofer.

One "limitation" (that's also a benefit), is it's ultra-low Fs of 10Hz.

Downside, or benefit? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

THE BOX: Many experiments have concluded that the best box is a sealed box that shows the Cyclone 2.0 to 2.5 cu.ft. Remember that the Cyclone displaces .5 cu.ft. by itself. If the Cyclone will be inside the box, make it 2.5 to 3.0 cu.ft. If the motor is out of the box, make it 2.0 to 2.5 cu.ft. For rock, rap, or most other popular music, use the smaller size box. For the ultimate in smoothness and transient response, use the larger size box. You can mount the Cyclone at any angle either in the box or with the motor exposed. Build the box as strong as possible using MDF or better material. Line the box with a few inches of polyfil or other acoustical material
How does it perform in a ported box? Why even no mention of ported boxes?

It would perform in a ported box, but with that Fs of 10Hz, it would require a pretty low tune, possibly prohibitively long port lengths.. (but there's always PR's! //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif).Like other subwoofers, this one is simply better suited to sealed enclosures, by design, not by any fundamental limitation.

THE AMP: We can't stress this enough, the Cyclone doesn't need a ton of power to do its job. That's one of the best things about it. It only needs about 150 watts continuous (300 peak) for full excursion @ 20Hz. Choose an amplifier with about 300 to 600 watts rated power bridged @ 4 ohms (remember that the Cyclone is an 8-ohm driver)
Have/Can the companies with the license on this servo-sub technology create one that will move more with more power, or is there a fininite limitation on the amount of effective excursion?

It's a limitation thermally, you simply don't need any more power, and the little motor apparently can't take more than 300 RMS. I've had 400 on mine for short periods of time, no issues...But you definitely KNOW when you've reached your excursion limits, it starts buzzing as it touches down on those foam pads.

I wish all subwoofers were so clear in shouting "that's all I got, dummy!" //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

ServoDrive uses the PacSci motors that I have on my table there... they handle a bit more power...

But again, it's all relative.

If subwoofers traditionally were 50% efficient, and we've all grown up thinking that 50 watts of power was a monsterous amount resulting in tremendous bass, then we'd be shocked we'd "need" 300 watts to drive this thing.

Put what you know about power and how it relates to output out of your mind completely. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

300 watts is tremendous, in the scope of a subwoofer that has something on the order of 10% efficiency... compared to traditional subwoofers that average at about 1% efficiency. In effect, this means that this sub, with 300 watts, would potentially yield the output of a traditional sub on 3000 watts (all other factors being equal). //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif

 

[geolemon 10+ year member]

THE CROSSOVER: Use only active crossovers. Never use passive crossovers with the Cyclone. Use a steep (minimum 18dB per octave) crossover between the mid-bass drivers and Cyclone. The crossover point should be no higher than 60Hz. You may even go as low as 50Hz. The idea is to make it impossible to tell where the Cyclone is physically located. The only way to do this is to keep frequencies that can be localized (above 50 - 60Hz) out of the Cyclone.
Are they telling us not to let it play those frequencies because they're "directional" or because this device can't play them worth a ****? I know that sounds accusatory, but I've never heard or seen one of these things before, and I'm quite skeptical.

The bottom line here is this: The cyclone wasn't that expensive, nor was it extremely hard to come by, but for some reason it's not still around. Is this a product of the limited interest in such a strange device (hence people's resistence to change) or is this because of the limitations of the driver itself? Basically, if it were so ****ed good, why isn't it still around, and why can't I find one to play with?

Remember, design issues vs. fundamental properties... //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gifWe really can't draw any conclusions about 'rotary servo subwoofers' as a whole, because the only rotary servo subwoofer ever to hit the market was the Cyclone.

So how can you draw conclusions about the technology as a whole, based on the design and performance of one specific model and example?

You can't, realistically, any more than you could comment on the technology and capabilities of 'voice coil subwoofers' on the whole, based on the design and performance of say... looking only at the MTX Thunder 8000. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

There are all sorts of factors to tweak - the same factors, in fact, as voice coil powered subwoofers. There's an analogous part on the Cyclone to literally every part on a traditional loudspeaker.

And it was very expensive, when it first came out... I don't know where you gather that it was inexpensive - $1200 worth of expensive, in fact.

Granted the prices dropped over the years, but is that due to reduced cost of production, or because they were finding it hard to market to the audiophile marketplace, and even more difficult to market to the less-experienced (but greater in mass) common audio marketplace, forcing them to cut into profits?

Eventually, it was discontinued - I'd say that's virtually proof of the latter. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

I'd still hardly call it an inexpensive driver, they still fetch hundreds of dollars, used.

 

[geolemon 10+ year member]

The Cyclone wasn't that expensive ? Dealer cost was over $1000 Canadian in 1999 (~$700 US) ...

Thank you... keywords "dealer cost"... not "price"!

Actual MSRP was about $1,200 USD, when it was first released in I believe 1994, by 1999, that number may have gone up or down, I'm not sure...

Usually MSRP is set about double of what distributors set "dealer cost" at - which some shops actually do charge. //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

That would seem to indicate an MSRP in 1999 of about $1,400, which sounds right, usually things inflate.

There was some price deflation I'd heard, at least late in the game - and that was simply observed via street prices - I don't believe this was a result of MSRP dropping (implying that PG was charging less), but rather of the shops cutting their profit margins, selling cheaper, responding to a fairly cold demand (I hypothesized my reasons above //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif)...

Ordering fewer, causing the distributors to lower their profits and prices to incent purchases...

Which eventually caught back to PG, who finally discontinued it. //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

When it came out, it was absolutely the most shockingly high-priced subwoofer that I'd ever heard of...

Even more shockingly impressive and high priced was a stillborn "big brother" - the very ServoDrive-'ContraBass'-like PG Vortex was supposed to be released, at an even higher price (and even higher displacement, a rotary-to-linear motion converter driving a pair of 15" cones), something over $2000 for MSRP, with a clear acrylic chassis, the prototype was **** sexy... too bad it was never released.

I wonder if it was disappointing first year Cyclone sales that led them to not release the Vortex.

 

[LoneRanger 10+ year member]

Thanks for the explaination, geolemon. I've been reading about Danley's servo systems all day and I'm starting to understand the benefits of the technology. However, I still don't understand why, if the technology is so far superior to classic loudspeaker design, that Danley doesn't just drop his technology fee in liu of mass marketing. We all know that you can make a million $20 a a time just the same as you can $50 at a time //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif I think that if all the benefits you and other enthusiests believe are there REALLY are there, most of us would be more than willing to give up the price of a w7 to own one of these beauties.

The only question that you and my extensive reading leaves me with is "as of right now, what are the limitations on the displacement of this thing?" If it will displace an insane amount of air with 300 watts, why not build a motor that will allow it to be fed say 600 or a thousand watts. I understand the efficiencey part of it, but the SPL'er inside of me wants to see something that will throw out sound at mind blowing pressure levels. Is the design for a larger motor in the works, or is the technology currently limited to low-wattage drivers?

 

[paikiah 5,000+ posts]

I thought the Aura 1808 neodymium sub was THE most expensive back in 1995. Guess not...

anyhow, say if this darn thing uses a motor to push/pull the membrane or whatever, THEORETICALLY, can't it have an infinite xmax too?

 

[kingpin_jeffie 10+ year member]

... Time to start selling drugs //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

completely understandable

 

[geolemon 10+ year member]

...I still don't understand why, if the technology is so far superior to classic loudspeaker design, that Danley doesn't just drop his technology fee in liu of mass marketing. We all know that you can make a million $20 a a time just the same as you can $50 at a time //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Well, that's assuming that money is his main motivator. Controlling the technology may be his main motivator. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gifI'm sure that regardless, he's not hurting for money.

...The only question that you and my extensive reading leaves me with is "as of right now, what are the limitations on the displacement of this thing?" If it will displace an insane amount of air with 300 watts, why not build a motor that will allow it to be fed say 600 or a thousand watts. I understand the efficiencey part of it, but the SPL'er inside of me wants to see something that will throw out sound at mind blowing pressure levels. Is the design for a larger motor in the works, or is the technology currently limited to low-wattage drivers?

Well, there's two different questions there:

1) what limits the displacement of the sub

2) what limits the powerhandling of the sub

//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

The displacement is limited in the same way that traditional subwoofers are... the diaphragms can only move so far before bottoming out on something physically, or until the suspension becomes too stretched...

With the Cyclone,it's 38 degrees of motion before the moving vane would crash into the two curved ramps.

I don't believe it's torsion rod - which is about 12" long - would run out of "twist" so soon. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

That's not an inherent limitation of a servo sub - if you click the link on my page (the link to my custom servo sub project) you can see that I'm building my own servo sub, and integrating the design of the actual raw subwoofer driver into a bandpass enclosure, to eliminate the need for curved ramps at all, which brings my excursion theoretically to nearly 180 degrees peak to peak before I'd smack into the necessary dividing wall... and my suspension that I am doing would probably run out of juice before that... but it's not the most sophisticated... I'd still probably get over 120 degrees.

The size of the vane, both in length and width, affect displacement... and the swing-weight affects excursion obviously also.

Thermally, the sub is limited in a similar way as a voice coil's windings define it's thermal limitations.

The motor in the Cyclone is the smallest motor that I've ever seen in any servo sub - so it makes sense that it's not designed for pure SPL powerhandling...

And again, who cares about that, when 300 watts to a 10% efficient sub is identical [in terms of SPL output] to 3000 watts on a 1% efficient sub (and typically, SPL subs are the ones less than 1% efficient //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif).

If you are interested in some SPL comparisons, click the links for the ContraBass and BassTech7 on ServoDrive's web page , check out the SPL comparisons they have to traditional subs, in some pretty huge pro-sound applications. //content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif