[Rclark]

You meant like the ULS15 in northeastern GTG vs  E15. The host (Gorilla) said the Rythmik E15 sounded "by far" cleaner than ULS15.

I don't know anything about a ULS, I'm sure that's quite possible. But there was no ULS in this comparison.

[rythmik]

Hi Brian,

Still enjoying my Servo 12s (since 04).
Can you explain what aspect of the soundwaves <200hz (subwoofer frequencies your amps operate at?) account for the changes in what you are hearing between these caps, opamps and resistors, etc? Are these amplitude, or some form of distortion variations being detected in the soundwaves <200hz? Do the heard changes reach the cochlea via these soundwaves, or by alternate means of conduction?
I'm quite curious to figure out whats going on here and you seem quite adept at relying on science for explaining things. Thanks.

cheers,

AJ

AJ, you again want to get me into trouble.  When I select a particular caps or resistors, I go with the brand name, for their quality control, for their source material selection criteria, for their manufacturing process. The sound difference is very subtle and it can come from any of the aspects that I mentioned above. As companies compete for low pricing, they will cut corners whenever they can.  You can buy caps from an unknown source and have no idea of how the cap is made. Other aspect includes the memory effect of the material.  I am not into the business of these passive components. I only take note of the sound difference if I hear one.

Now semiconductor such as OPAMP is totally different and easier to explain. I still remember one of the papers I read when I was in graduate school was a case study of an opamp (I think it was the predecessor of the uA741) that when it was under heavy load, the gain can become negative (gain negation) and it stays that way for a while even after the load has been removed.  It turns out as OPAMP is made of tiny silicon chip (or die), when the output transistors work hard, it heats up that part of die first and then the heat spreads to other input stage in an uneven fashion. And the heat does not go away immediately. That becomes a memory effect.  After that lesson, the circuit topology has been changed and thermal stress is added to design criteria. Still I have seen some audiophiles biased their opamp output stage into class A operation and yet my concern is whether such a unbalanced thermal stress impact as memory effect can happen to those opamps. I sure hope they have read the same paper that I have read.  Other factors affecting the sound quality is the complexity of the IC manufacturing process (or steps).  Cheap opamp uses far few number of process steps (and/or smaller die size) and they have very weak or poor characteristic P transistors.  Expensive OPAMP such as OPA627 is expensive simply because the number of processng steps of manufacturing is higher in order to create more ideal and better matched transistors.  Some opamps even have laser trim process to better match the resistor/or transistor. So not all opamps are created equally.

I don't think my view on the above is unique in anyway.  One thing we all need to understand is there is no motivation for well-trained and qualified engineers to investigate how caps or opamps affect sound quality. There is simply no money, nor fame in there.  That is the reality.  It is far easier to say there is no difference than spend our brain power to figure how it is different.  I really think a lot of those type of conclusion is out of laziness.


 

[JohnR]

Impulse reponse can be transformed from frequency response and vice versa when the system is "linear" and "distortion free".  The two are mathematically the same thing. blah bla... But the impulse and frequency response begin to diverge when the system is in nonlinear region.

OK, so the measurements to get impulse or step response can be done at a low enough level so that the system is close enough to linear. As Danny said, earlier in the thread: "And the stopping power and control of the servo system is quite evident even at lower volumes." We still haven't seen anything to demonstrate this "stopping power".

Then how do you quantify the distortion induced in the measurement. You need to specify at what outputs level that you want the measurement.

The levels and frequencies would be decided in discussion. I don't see why there's an obstacle with this one...

To do a fair comparison, we need to EQ the two systems to have almost identical FR and phase response  and then push them to same large signal level with induced distortion.

Fair enough on the FR, although as above, it doesn't have to done at large signal levels. But there are really two questions here and you've focussed on only the second. The first is whether the benefit of the servo can be shown with the same amp and driver. The second, which would (or could) be more collaborative, is whether we can come up with a way to make a meaningful ("objective"/measured) comparison with different drivers/systems across continents.

Hope that's clearer - ?

[jtwrace]

No, you get the wrong idea.

How so?

I do discourage customers to do any mod. 

OK.

Some customers do ask the benefit of changing out the power filter and I did say the benefit of upgrading them to say Panasonic power caps may not be that significant (I used panasonic power filter caps in H600 amps so I have the idea of how they sound). 

So, all caps on the amps will benefit from Panasonic caps?  Can you explain why and can you post any data on this? 

I wil do it first.

I vaguely remember this is what you told me.  You simply put in the amps what you thought was the "best" so nobody had to fool or think about it.  I've used Rythmik subs now for years and they're superb.  I truly believe that proper setup and implementation is much more important than any cap, resistor or wire on a subwoofer.  This was proven with measurements of my two Rythmik subs along with my two bandpass subs. 

[AJinFLA]

AJ, you again want to get me into trouble.

No sir. I was hoping your PhD EE knowledge could shed some light on the very specific questions I had. Remember, the thread is about dipole bass (for Maggies, but has morphed into the general case). Your servo system was recommended. Please keep in mind I was A) an early adopter, giving you plenty of props on the old madisound board (which Danny and Dave should remember) B) asking you for a dipole version immediately, as I was at the time (04) using dual non-servo 12 dipoles. This is well prior to you doing them. So I'm "on board" as far as their efficacy. However, you are making quite specific claims about certain aspects, that I hope we can agree, should have a rational, scientific explanation. What aspect of the soundwaves account for what you are hearing with the resistor, caps, opamps, ____, etc, etc. here, at <200hz frequencies? As a PHD EE, do you have an electro-acoustic explanation?
Thanks.
Btw, I use Mills in my XOs, because I have found that some sand casts are not as non-inductive as purported...a physically measurable effect that falls within known audibility thresholds.

One thing we all need to understand is there is no motivation for well-trained and qualified engineers to investigate how caps or opamps affect sound quality. There is simply no money, nor fame in there.  That is the reality.  It is far easier to say there is no difference than spend our brain power to figure how it is different.  I really think a lot of those type of conclusion is out of laziness.

Incorrect. Clarity Cap did all of the above, precisely because if there was such an effect, it would help them market their product for financial gain, just like any other product that can show benefits from scientifically rigorous results.
They managed to maintain the 100% failure rate for scientific testing of audiophile beliefs.
Please never let the failure of others be an excuse for why your scientific claims become unverifiable. The high end is already overloaded with that.

cheers,

AJ

[HAL]

Audio Magazine published an article in 1980 about measurements of capacitor differences by Richard Marsh and Walt Jung.  Here is a link:

http://www.reliablecapacitors.com/pickcap.htm

Still have the original copy at home.  This is why I modified my Maggie IIB crossovers.   Sounded better to me with improved caps. 

Now back to the original programming.

[rythmik]

John/AJ,

I have a sense you guys are not really EE trained.  Can you any of you two give me a definition of linear time-invariant system, in mathematical equations? Then we can go on with other discussion.  After you read the equation, you will the audio system is far from being time invariant system. Here is not even a standard test for it. I think most of us forgot about that. THD, FR, impulse, step, are all just steps into trying to simplify problems. The engineering approaches are trying to simplify problems. But do we lose details in the process? Sure. That is why we need to justification to assumptions we make.

[rythmik]

How so?
OK.
So, all caps on the amps will benefit from Panasonic caps?  Can you explain why and can you post any data on this? 
I vaguely remember this is what you told me.  You simply put in the amps what you thought was the "best" so nobody had to fool or think about it.  I've used Rythmik subs now for years and they're superb.  I truly believe that proper setup and implementation is much more important than any cap, resistor or wire on a subwoofer.  This was proven with measurements of my two Rythmik subs along with my two bandpass subs.

Jason, You need to understand. Replacing caps and resistors are tweaking. I have done tweaking in the past in my life and I don't want to do it again because  I have no time for it. I have 2 so-called audiophile cables at home: One kimber KCAG and one Clear Audio Discovery signature.  They sound differently. I am so familiar with them if someone want to bet $50,000 that I cannot hear the difference,  I will accept the challenge if it is conducted in my home in exactly my system under uninterrupted condition (not a bunch of people talking, drinking).  Let us start the Trump thing except I want their money in bet.  Some opinions here is like if I cannot hear the difference, no one else can. That is arrogance in work.  Those are typical for people who don't work in EE industry (not software engineering)  If they do, then they know there are too many things not taught in textbook. An college graduate needs at least 10 years more training in actual work experience. There are so-called "best practice" in industry because there is no clear guidance beyond textbook. 

[Danny Richie]

I couple of things here.

First, Brian, please be patient with these guys. You designed a more advanced now patented technology that is not easy to understand. And unfortunately not easy to demonstrate by measurements for various reasons. You have to expect this kind of debate on these forums now and then. Don't take it personal or make your responses personal. You can't just tell them that they don't have the experience to understand or to get a life. Again be patient and just come back to this when you have time.

John,

Yesterday before I headed out for soccer practice I took some more measurements. I realized I had two amps that Brian sent me a long time ago for me to develop my V-2 kit. It was one of his amps that he added a transform circuit to and it had no servo system.

So I still had the Super-V set up for measuring and was able to swap out the two amps for back to back responses. Again I was having to make near field measurements. At first I just measured them both with the crossover setting turned all the way up. The impulse response of the servo system was considerably cleaner but the non servo version was also playing up higher. So after some adjustments to the crossover range and filter extensions I got the two output to look pretty close, but it still played much lower with the servo amp. Then looking at the impulse response the differences weren't great enough to call anything one way or another. There just wasn't enough woofer movement to amount to anything. At that distance I can only use a fraction of a watt or it will max out my mic. I tried backing the mic up a few inches and bringing the power level up but that was still really low level, and I couldn't back away too far or I picked up room related effects in the measurements.

I am not sure at this point how to show this in measurements. The servo system creates more and more difference the harder it is played. At normal to even low volume levels it is pretty easy to hear also, but that is at power levels way beyond what I can measure at near field. It will simply max out my mic.

I brought some woofers in yesterday to warm up and will try to take measurements later today. They really need to warm up to room temperature and I really need to send a signal through them for a little while to get some decent T/S parameters.

[lowtech]

John/AJ,

I have a sense you guys are not really EE trained.  Can you any of you two give me a definition of linear time-invariant system, in mathematical equations? Then we can go on with other discussion....

This is precisely why you and Danny are permanently banned for life from either posting on HTGuide or having any customer even discuss any of your products there.  Perhaps you will end up having the same restrictions imposed on you here?

http://www.htguide.com/forum/showthread.php4?t=28354

"There are two companies who's products we do not discuss at all. These companies are GR-Research and Rythmik Audio. Why don't we not allow discussion regarding products from these companies?

1) We were informed by Brian Ding that in his opinion those lacking IEEE or similar level education weren't qualified to comment about his products in comparison to others. Very few posting here have such credentials, and for those that do it's rather impractical to post proof. As a result there will be no discussion of Rythmik Audio products in the Missions Impossible forum.

2) Historically it's been most problematic to host rational discussions about GR-Research products, all the threads end up getting locked.

Problem being it's tiresome dealing with rants of fanboys, people shilling the products, or the inability of the designer to entertain any form of critical discussion regarding the products. So this is another situation where there will be no discussion about products or a design using the products."

[Danny Richie]

Brian,

Also keep in mind that some of these guys do not have experience in hearing differences in things like capacitors, wire, resistors etc. And unfortunately dismiss the possibly of their being a difference unless they can see objective (measured) differences. There is always this group out there and getting into a debate on those things never yields any results. The only way for them to understand is for them to witness the same things others of us have.

And as for amp mods, my guess (knowing Dave) is that will likely attack the power supply to lower the AC noise floor or increase the power supply caps and by-pass them with faster discharge caps as well. There is some room there for improvement.

[Danny Richie]

This is precisely why you and Danny are permanently banned for life from either posting on HTGuide or having any customer even discuss any of your products there.  Perhaps you will end up having the same restrictions imposed on you here?

http://www.htguide.com/forum/showthread.php4?t=28354

"There are two companies who's products we do not discuss at all. These companies are GR-Research and Rythmik Audio. Why don't we not allow discussion regarding products from these companies?

1) We were informed by Brian Ding that in his opinion those lacking IEEE or similar level education weren't qualified to comment about his products in comparison to others. Very few posting here have such credentials, and for those that do it's rather impractical to post proof. As a result there will be no discussion of Rythmik Audio products in the Missions Impossible forum.

2) Historically it's been most problematic to host rational discussions about GR-Research products, all the threads end up getting locked.

Problem being it's tiresome dealing with rants of fanboys, people shilling the products, or the inability of the designer to entertain any form of critical discussion regarding the products. So this is another situation where there will be no discussion about products or a design using the products."

Mike, I have never been banned from there. I still have an active account there as far as I know. Discussions of our products there by my customers lead to a subjective verse objective debate that they did not want to deal with anymore. My customers wanted to talk about subjective differences that they heard from cap upgrades and stuff and they didn't want to deal with those discussions.

And I can't believe you of all people would bring up being banned from site. Are you sure you want to go there?

[rythmik]

1) We were informed by Brian Ding that in his opinion those lacking IEEE or similar level education weren't qualified to comment about his products in comparison to others. Very few posting here have such credentials, and for those that do it's rather impractical to post proof. As a result there will be no discussion of Rythmik Audio products in the Missions Impossible forum.

You got to be kidding me.  Who wrote that IEEE thing?  IEEE is not education degree or anything.  It just shows how clueless this person is and whoever quote it. IEEE is a society.  You don't get a degree in IEEE. But you can submit peer reviewed papers to IEEE's various Journals. Professors get fame and students get  Ph.D degrees that way.  I know the person who wrote this, Thomas.  He was a retired frensic pathologist.  He wants to build a bunch of following in htguide, sort of like building his second career after retire. He also wants to do that outside htguide.  Nobody give him any sh** outside htguide. The only hole he can hide is htguide. You can tell Thomos I say this.  His is supposed to be respecting professionals. I don't do his job and he does not do mine.
 

[jtwrace]

John
I have a sense you guys are not really EE trained.

I could be wrong but I'm pretty sure JohnR has an E.E. and PH.D., Engineering and Computer Science.   

[Danny Richie]

Yep, Thomas was the ring leader over there and was the guy that was always freaking out for the subjective stuff. He jumped all over me on another forum for selling foil inductors and Blackhole 5 damping material and felt like he had to warn everyone that I was a snake oil salesman or something.

I hate even responding to this stuff here on AC, but if it is going to be brought up surely I can respond to it.

And hey everyone, can we not make this stuff personal? No need to bring up everyone's credentials, education levels, or forum bickering from many years ago. Come on guys!

[lowtech]

You got to be kidding me.  Who wrote that IEEE thing?  IEEE is not education degree or anything.  It just shows how clueless this person is and whoever quote it. IEEE is a society.  You don't get a degree in IEEE. But you can submit peer reviewed papers to IEEE's various Journals. Professors get fame and students get  Ph.D degrees that way.  I know the person who wrote this, Thomas...

Well, as it happens... I do have an A.S. degree in electronics technology and a B.S. an another engineering field... and have no trouble communicating with Ph.Ds at work.  As far as the ban goes, it's been in place for years now.  So, who is it that doesn't have a clue?   

Oh, I'm also a member of IEEE.  Do you need to see my card?   

And hey everyone, can we not make this stuff personal? No need to bring up everyone's credentials, education levels, or forum bickering from many years ago. Come on guys!

It was your guy who brought this up... again.   

Brian, this brings up another interesting point.  Does your guy, Danny, have sufficient education credentials to do business with you?  I assume you two need to speak in order to exchange $$$.

[jtwrace]

Also keep in mind that some of these guys do not have experience in hearing differences in things like capacitors, wire, resistors etc. And unfortunately dismiss the possibly of their being a difference unless they can see objective (measured) differences.

Who is this directed towards?

[rythmik]

I couple of things here.

First, Brian, please be patient with these guys. You designed a more advanced now patented technology that is not easy to understand. And unfortunately not easy to demonstrate by measurements for various reasons. You have to expect this kind of debate on these forums now and then. Don't take it personal or make your responses personal. You can't just tell them that they don't have the experience to understand or to get a life. Again be patient and just come back to this when you have time.

For the record, I did get utterly furious when John said servo for OB is a gimmick.

[Danny Richie]

Who is this directed towards?

Don't worry buddy, you're not the only one in that camp. AJ and I went at it for years on that stuff.    Funny thing though. AJ and I have gotten to know one another now and even went to dinner together at LSAF. Come to find out, he's a pretty good guy. I now consider him a friend. We can disagree and it not be personal.

[jtwrace]

Don't worry buddy, you're not the only one in that camp. AJ and I went at it for years on that stuff.    Funny thing though. AJ and I have gotten to know one another now and even went to dinner together at LSAF. Come to find out, he's a pretty good guy. I now consider him a friend. We can disagree and it not be personal.

I'm not worried whatsoever.  It's not about hearing or not for me, it's more about putting an emphasis which yields a much larger improvement.  For example, four subs, setup properly, yields me a much greater positive result than any cable that I've tried has.