Servo Controlled VS Non-Servo Controlled Infinity Woofers?

Infinity!

Well-Known Member
Hey guys... Happy New Years!! :)

Just wondering if people can share there experiences and insights with Infinity's servo controlled woofers (IRS, Beta, Delta/Gamma, Epsilon, etc.) versus their non-servo controlled woofers (RS 4.5's, IIb's, and most importantly Kappa 9's, etc.).

For the sake of this discussion, i'm only talking about the reproduction, sound clarity, and impact of the bass... not how low (hz) the servo controlled woofers can get. I know they can get much lower, but I'm more interested in SQ. I'm sitting here right now listening to my Kappa 9's and i'm thinking to myself, "How much better can bass reproduction get with servo controlled woofers, because these sound damn good!"

Anyways, thanks in advance for your input!
 
The servo woofers sound much better, they hit harder, are more accurate, go deeper and have tighter/pluckier/more tuneful bass.


With a sevo system, The input goes through a comparator circuit that
compares it to the actual cone motion of the woofer and then cone motion is corrected

The servo brings the woofer quickly back to dead center or to the woofers original resting position after a note is played, in fact if you try to push a servo woofer back in it's cabinet with your hand it will forcefully push back at your hand trying to get back to dead center, a kappa woofer will easily push back in it's cabinet when that same pressure is applied.

kappa woofers have more of a pendulum effect with less control, when a note is played the woofer will go back and forth before resting at dead center adding distortion that some people will perceive as having more bass, the kappa woofer has to rely on it's magnet and it's sealed inclosure to bring it back to dead center.

If you turn off the SCU box on a servo woofer and run the woofers like normal woofers there will be noticeably more bass at first listen but you will quickly learn that the quality of bass is gone.

Don't get me wrong my kappa 9's bass is very good but when compared side by side to the epsilons bass, the servo woofers take it to another level.
 
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The servo woofers sound much better, they hit harder, are more accurate, go deeper and have tighter/pluckier/more tuneful bass.


With a sevo system, The input goes through a comparator circuit that
compares it to the actual cone motion of the woofer and then cone motion is corrected

The servo brings the woofer quickly back to dead center or to the woofers original resting position after a note is played, in fact if you try to push a servo woofer back in it's cabinet with your hand it will forcefully push back at your hand trying to get back to dead center, a kappa woofer will easily push back in it's cabinet when that same pressure is applied.

kappa woofers have more of a pendulum effect with less control, when a note is played the woofer will go back and forth before resting at dead center adding distortion that some people will perceive as having more bass, the kappa woofer has to rely on it's magnet and it's sealed inclosure to bring it back to dead center.

If you turn off the SCU box on a servo woofer and run the woofers like normal woofers there will be noticeably more bass at first listen but you will quickly learn that the quality of bass is gone.

Don't get me wrong my kappa 9's bass is very good but when compared side by side to the epsilons bass, the servo woofers take it to another level.

Oh okay, that makes sense! You say that the sheer amount of bass is reduced between your epsilons compared to the k9s. Is this because there are 2 less drivers or because servo controlled woofers are quiter? Or a combination of both possibly?
 
Oh okay, that makes sense! You say that the sheer amount of bass is reduced between your epsilons compared to the k9s. Is this because there are 2 less drivers or because servo controlled woofers are quiter? Or a combination of both possibly?

The output of bass on the epsilon can be more or less than the k9's bass by simply adding more or less gain with the SCU but if I put the gain at flat or 0... the k9 has slightly more bass probably because of the two extra woofers and because the epsilon servo woofers have less distortion.
 
I've never heard a Servo Infinity, I wish I could.
I do know that no matter how much I love the bass of my Kappas, the bass of the Ren 90 with that Watkins woofer is far, far, more accurate if not louder.(it is NOT louder) it's much more restrained, but when there's a recording with true low bass, the Rens reproduce it all, where my kappas, it starts to disappear somewhere in the mid to upper teens, I'd guestimate.
 
I've never heard a Servo Infinity, I wish I could.
I do know that no matter how much I love the bass of my Kappas, the bass of the Ren 90 with that Watkins woofer is far, far, more accurate if not louder.(it is NOT louder) it's much more restrained, but when there's a recording with true low bass, the Rens reproduce it all, where my kappas, it starts to disappear somewhere in the mid to upper teens, I'd guestimate.
I agree with you in that the rens bass is more accurate than the k9's, the servo woofers take some getting use to their sound, they are even more accurate than the rens.
 
How does this system differ from the Infinity servo subwoofers? I've heard from time to time that they are not a true "servo" system. 2nd could a pair of speakers (just the woofers or maybe the amp that is used for the woofers) be modded to become servo controlled. 3rd there are several amplifiers I have come across which are servo power amps. the legendary arc d-250 tube amp comes to mind, what is special about them? Kind of understand there is an inaudible signal sent to the woofers (feed back?) to get them to returned faster to the neutral position and there is something special about the woofers as they have an extra piece of hardware on them but that is about all I get and to be honest I don't even slightly understand that.
Thanks
Jim
 
How does this system differ from the Infinity servo subwoofers? I've heard from time to time that they are not a true "servo" system
Don't quote me on this, but it's my understanding that the SSW-10/Infinitestimal Sub (they're both the same) are not true servo subs, but the SSW-210/212 are (they should be, for what they originally sold for). While I do own both an SSW-10 and SSW-210, I've never opened them to compare.
there is something special about the woofers as they have an extra piece of hardware on them
In multi-woofer Infinity servo systems (I believe most, if not all Infinity servo systems, other than the Servo Statik, have more than one woofer), one of the woofers has an accelerometer attached to the inside of the voice coil. This accelerometer sends a signal via a separate cable back to the servo control unit. The control unit compares the signal from the accelerometer to what it expects based on the signal that is currently being sent to the woofers, and if they differ, it adjusts the output to the woofers accordingly. You'll note that each Infinity servo controlled system has a unique servo controller. That's because the expected signals from the accelerometer vary based on the woofers and cabinet design.
 
The original Modulus sub is a single 12 with accelerometer and external servo control . I believe this is the only single driver servo sub from the Chatsworth boys. I also have an ssw10 and while it is very fine and great in small rooms, it does not have any external control or accelerometer on the VC.
 
If anyone wants to hear good servo-controlled subwoofers, check out
Rythmik Audio. You can buy the components to build your own or buy
finished units. The sound quality is excellent. You could find a pair
of Renaissance 80's and add one or two of these subwoofers for a
great sounding system.
 
All i know is i have a pair of Delta's and would love to try the servo on them to hear the difference :) and of course complete the transformation to Gamma :p .. alas no buneo for me

But to the point of the thread, the delta and gamma A+B test would be probably as definitive explanation of the difference in experience as could be asked for as literally deltas are the Gamma without the servo control unit
 
If I run my epsilons without the servo connected the bass is loose and boomy, with the servo connected the bass is tighter and way more accurate, it hits much harder and goes deeper too.
 
It's a shame that the control woofers and servo controllers are so rare and expensive. Otherwise, it wouldn't be too hard to upgrade the Kappa 9s to a servo system. One control woofer in each, and a small mod, to allow for a connection from the controller, and that'd be it. A Kappa / Gamma hybrid. :naughty:
 
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The mod you suggest would have to include bypassing the internal woofer-section crossover to the woofers when using the SCU, also. I think that's part of the improvement in sound quality when using the SCU/servo system: the woofers are connected to the amp directly with no other components in the way of the signal
 
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