[AudioCats]

why discuss? It is so much easier to just ask your professor.
 

 

 

[dvw]

The Nordost test has been discussed here.
http://www.head-fi.org/forum/thread/471315/some-scientific-data-on-isolation-power-and-cables

 

[9pintube]

maverickronin and others,     No one said you couldn't use your "LAMP CORDS" There are several camps concerning cables and wires!  I think we know about the different sides many members are on, concerning this subject.............PS, nice parrot.. 

 

[BIG POPPA]

Quote:

why discuss? It is so much easier to just ask your professor.
 

 

Listen to this guy. Kevin tunes his gear with different cables. I have auditioned his gear.
 

 

[Prog Rock Man]

Quote:

'Tis a lesson you should heed, Try, try again. If at first you don't succeed, Try, try again. Just kidding, I'm with slim.a when he says it's best not to do tests if you can't do it right. Not because I'm against pointless research, but because people like to make faulty conclusions. You falsely believe that if there is a difference it must be reliably heard. Wrong. That's like saying if a monkey could shoot a three pointer he should be able to do it consistently, when he only has to do it once, maybe once in a million attempts. Think about it.

To clarify my original post, I said reliably and consistently, by which I accepted there may be exceptions. Otherwise I would have said in all cases, every time. However, your monkey being able to shoot something once in a million attempts does not make me want to accept he can target shoot. I prefer to accept that your monkey cannot shoot and hit a target, unless by once in a blue moon, miraculous, fluke. 
 
I reality, I would not go any where near an armed monkey.

 

[High_Q]

Quote:

You don't seem to understand what I was trying to say, so allow me to rephrase:
 
If you won't to test the effect of a change in power cable, it is stupid to try and find a difference in a simple sine wave. What we listen to is not simple sine waves but a complex musical signal.

So far, there is no easy way to measure a musical signal properly. If you look at simple measurements like RMAA, a poor sounding soundcard such as the emu 0404 usb might measure better in the frequency domain than the $27,000 Naim CD555 Cd player. The reason is pretty simple it doesn't cost more than $100 to make a DAC with a good frequency domain performance but it take a lot more to make one with a good time domain frequency. In fact, Kunchur wouldn't have needed to use higher sample rate to generate a proper signal from a CD player. A CD player such as the Naim CD that use R2R dac chips with good digital filters can in fact generate decent sine waves at high frequencies (contrary to sigma delta DACs - see here for example).
 
Saying that "there will be no difference between a chunky monoprice cable and a probably-costs-more-than-my-car Nordost cable" is a stupid comment if:
a/ you didn't measure it
b/ you didn't even try it

For lack of understanding and for close mindedness people believed for a long time that the earth was flat. More recently all CDs were supposed to sound the same (Perfect sound forever) until people started complaining and we discovered jitter.
 
A fraction of audiophiles have been saying for some time that they noticed a difference between power cords (and vibration control devices). Nordost is trying to come up with a way to prove there is a measured difference (the same way we have ways to measure jitter today).
 
Science is constantly evolving. Some assumptions that were considered being true a hundred years ago have been revised/updated today. If you want to believe there is 0 possibility that a power cord can affect the sound, good for you. Nobody is forcing to buy a Nordost power cord.
Personally, I have found differences between power cords, so I will keep using the ones that improve the sound in my system. If at some point, measurements prove that what I am hearing is true then I would have spent my money wisely. If there is no proof (ever) that power cords can affect the sound, I still don't care as it allowed me (for whatever reason) to enjoy my system even more. The way, I see things I am aware of the risks of being "fooled" but I consider that the outcome in both cases is a win situation for me.

Back to the topic of measuring the effect of power cords, if someone wants to do the measurement, better do them right.

- Let's suppose that I am wrong, then we would have used over speced equipment for the test but we still would have good results.
- Let's suppose that you are wrong, measuring a simple sine wave to incorrect results.
 
Even if you don't agree with what I subjectively hear, the proper test conditions I suggested remain right.
 
Anyway, I have said enough on the subject. If people wish to discuss further whether it is possible or not that power cords affect the sound (other than by subjective listening), it is probably better to move the discussion to the sound science forum

I am rather annoyed with your response.  Nothing in what you wrote have any lick of reasoning in it.  Its just bla bla bla $$ bla bla bla analogy(forced analogy, bad analogy is bad logic, using analogy to reason is very bad), this cost more, this cost little, don't compare the two. Thats what it comes down to.  And that stinks of very low reasoning skills.  And what you wrote about science is so stretch to overgeneralization, I can safely assume, you have very little experience with science.  You have no right to generalize science, you talk like you know enough science to talk so freely about it.  Unless you have a Phd in a science field, don't tread that territory, it makes you look very foolish.  Just because you have the hearsay knowledge of some equipment, doesn't make you an expert.  Its very foolish to think so.

 

[Rdr. Seraphim]

High_Q
 
Please back off. Read some of Slim.a's other posts and I believe you'll find his approach reasoned and rational, as well as appreciated. No need to take this into the personal realm. If you find slim.a's post irritating, then just take it with a grain of salt, but try to be more even keeled, balanced in your criticism. Your response feels more like a personal attack. 
 
Quote:

I am rather annoyed with your response.  Nothing in what you wrote have any lick of reasoning in it.  Its just bla bla bla $$ bla bla bla analogy(forced analogy, bad analogy is bad logic, using analogy to reason is very bad), this cost more, this cost little, don't compare the two. Thats what it comes down to.  And that stinks of very low reasoning skills.  And what you wrote about science is so stretch to overgeneralization, I can safely assume, you have very little experience with science.  You have no right to generalize science, you talk like you know enough science to talk so freely about it.  Unless you have a Phd in a science field, don't tread that territory, it makes you look very foolish.  Just because you have the hearsay knowledge of some equipment, doesn't make you an expert.  Its very foolish to think so.

 

[slim.a]

Quote:

No offense, but nothing in what you wrote have any lick of reasoning in it.  Its just bla bla bla $$ bla bla bla analogy(forced analogy, bad analogy is bad logic, using analogy to reason is very bad), this cost more, this cost little, don't compare the two. Thats what it comes down to.  And that stinks of very low reasoning skills.  And what you wrote about science is so stretch to overgeneralization, I can safely assume, you have very little experience with science.  You have no right to generalize science, you talk like you know enough science to talk so freely about it.  Just because you have the hearsay knowledge of some equipment, doesn't make you an expert.  Its very foolish to think so.

As for me, I can safely assume that regardless of your background you clearly lack reasoning and deductive skills. I do have a solid background in science and math though I specialized in Finance and strategy consulting later on. I had worked a lot with engineers and while they can be good at their jobs, they can be to close minded at times and don't know how to think outside of the box.
 
What people were suggesting, measuring the effect of different power cords with simple equipment was stupid. It is like if you are trying to compare the speed of a 747 with a jet fighter using a radar that was made for measuring the speed of cars. It is plain stupid and will only lead to false results.
I use simple analogies because people are often too lazy to read articles that are long and complicated. If you had read Nordost paper or better, those published by Kunchur, you would understand what I am saying.
A few weeks ago, I acquired an AES paper on the subject of jitter made by Benjamin and Gannonn. Their methodology was good, their math was good but they made a few mistakes. They used cheap Sony headphones and unknown quality headphone amp and DAC to conduct their test about jitter. Now there are people that go all over the place and say you cannot hear jitter under 10ns like it was the absolute truth. Their test system was not representative of most audiophile test systems. I am the first to say that if you are going to use something like the little dot mkIII there is no point in upgrading the DAC, power cords... Everything is relative. If you don't understand that even scientists can make mistakes, I pitty you.
 
What I use is critical thinking and logic. My personal approach is the following: "If it measures good and sounds bad, it is bad. If it measures bad and sounds good, you've measured the wrong thing."
Instead of spending my time trying to explain why things don't or shouldn't work, I prefer spending my time trying things that work first and then try to find an explanation. 
 
Another "bad analogy" as you say. A lot of people complained about the poor sound quality of the CDs, especially in the highs, in comparison with LPs. Everyone with your reasoning would have discarded their remarks and say that CD was perfect sound for ever. Later CD makers discovered that jitter played a big role and started addressing that issue. Later on, when we moved from R2R dacs to the cheaper to make sigma delta chips, people started complaining about the poor sound quality of those chips dispite the fact they had better THD and SNR figures than the older 16bits R2R chips. Later on, we learned that sigma delta chips had a lot more out of band noise than R2R chips and were pretty poor at handling high frequencies in the time domain. If you have a doubt look at some sinewave pictures here : http://www.mother-of-tone.com/conversion.htm.
Of course, this is not the first time it happened in audio. When negative feedback appeared, some audio designers thought for a moment that it was the magic bullet that would cure any circuit from THD. They started coming up with amplifiers with vanishingly low levels of THD but that sounded horrible and wrong to all the audiophiles that listened to them. After much complaint, they discovered that the measurements they were doing (1khz constant signal for example) were not representative of real world usage. When using a live signal and high levels of negative feedback, if the system is not fast enought, the error that the system is trying to correct at the input is already gone. This causes time intermodulation distortion. So what seemed "sane" for engineers at some point was in fact generating a distortion worse than the one it was supposed to cure.
 
So forgive my supposedely bad reasoning skills and my obvious lack of understanding of science, but I don't put too much faith on what some self proclaimed scientists and engineers, like you, think the truth is. There are countless examples in old or recent history where people in different fields (audio but also medicine, physics, mathematics...) had to revise or correct their model of thinking. I don't pretend to know everything but in case of doubt, I prefer to trust my ears as it increases my personal pleasure, which is what this hobby is about.

 

[slim.a]

Quote:

High_Q
 
Please back off. Read some of Slim.a's other posts and I believe you'll find his approach reasoned and rational, as well as appreciated. No need to take this into the personal realm. If you find slim.a's post irritating, then just take it with a grain of salt, but try to be more even keeled, balanced in your criticism. Your response feels more like a personal attack. 
 

 

 
I just saw that High_Q corrected his answer to make it more of personal attack. Personally, I don't care, if he can't find arguments to attack my reasoning, I guess it is easier to try and discredit me.
 
What I tried to say so far in this is the following: if we are to do a measurement test, we should do the right one with the right tools, even if it seems overkill.
 

 

[SP Wild]

Hi Slim A.  Off topic, but how far will the Hi-face go as a transport, would it reduce jitter at the level of a professional CD transport mechanism?  I have been holding off from the HiFace, because I am certain that a new unit with a High quality low ripple PSU, better clocks with improvements in Async USB drivers is just around the corner.
 
Yeah, and the European financial crisis cost me $15,000.

 

[slim.a]

Quote:

Hi Slim A.  Off topic, but how far will the Hi-face go as a transport, would it reduce jitter at the level of a professional CD transport mechanism?  I have been holding off from the HiFace, because I am certain that a new unit with a High quality low ripple PSU, better clocks with improvements in Async USB drivers is just around the corner.
 
Yeah, and the European financial crisis cost me $15,000.

The stock Hiface is better than entry level CD Transports but it probably cannot match high end transports (for many reasons: PS supply to the clock, output stage...). As for me, I am currently using a modified battery powered Hiface which increases its performance by a significant margin... So there is room for improvement over the stock Hiface.
If you don't intend to mod the Hiface, i would suggest looking for a unit such as this: http://www.halidedesign.com/bridge/
Since this is out of topic, you can send me a PM if you would like so that we do not derail this thread.

 

[Rdr. Seraphim]

X^n! (and from personal experience, dang it!)
 
I haven't found a good measuring system that explains why good aftermarket AC power cords make the difference that they do. (Or good cabling in general!) The difference has always been tangible to me--sadly for my wallet, happily for my ears. We just haven't figured out a way to measure what it is that makes the difference.  
 
Similarly, I haven't seen any measurements to prove or disprove what folks like Bybee and their Bybee Quantum Purifiers actually do. It seems like anyone who has applied Bybee's purifiers to their music systems put their money on the line to keep 'em. Again, no one to the best of my knowledge has measured the difference these make in their systems. The military has put the technology to good use and presumably it's effective, and measurable. Apparently, multi-meters, o'scopes, and AP analyzers that us common folk have at our disposal may not have the resolution (or measuring capabilities) to be able to effectively measure what's happening, not to mention the ability to accurately correlate the results with the apparent improvement in sound quality.  
 
What does seem to correlate are the effects on SQ including, improved resolution, better bass, expanded soundstage, increased instrumental delineation and three dimensional image outlines. These seem to be some of the most common descriptors of a good quality AC power cord. I'm just sorry that not everyone hears the difference because the improvements really make my toes tap, and my head bob a little better, and I get goose bumps more frequently. I'm happier listening to music with 'em in my system than without. I enjoy the music more with 'em.   
  
 
Quote:

"If it measures good and sounds bad, it is bad. If it measures bad and sounds good, you've measured the wrong thing."
 

 

[JamesL]

 
 
 
Quote:

If you won't to test the effect of a change in power cable, it is stupid to try and find a difference in a simple sine wave. What we listen to is not simple sine waves but a complex musical signal.


So far, there is no easy way to measure a musical signal properly. If you look at simple measurements like RMAA, a poor sounding soundcard such as the emu 0404 usb might measure better in the frequency domain than the $27,000 Naim CD555 Cd player. The reason is pretty simple it doesn't cost more than $100 to make a DAC with a good frequency domain performance but it take a lot more to make one with a good time domain frequency. In fact, Kunchur wouldn't have needed to use higher sample rate to generate a proper signal from a CD player. A CD player such as the Naim CD that use R2R dac chips with good digital filters can in fact generate decent sine waves at high frequencies (contrary to sigma delta DACs - see here for example).
 

Saying that "there will be no difference between a chunky monoprice cable and a probably-costs-more-than-my-car Nordost cable" is a stupid comment if:

a/ you didn't measure it

b/ you didn't even try it


For lack of understanding and for close mindedness people believed for a long time that the earth was flat. More recently all CDs were supposed to sound the same (Perfect sound forever) until people started complaining and we discovered jitter.

 

A fraction of audiophiles have been saying for some time that they noticed a difference between power cords (and vibration control devices). Nordost is trying to come up with a way to prove there is a measured difference (the same way we have ways to measure jitter today).

 

Science is constantly evolving. Some assumptions that were considered being true a hundred years ago have been revised/updated today. If you want to believe there is 0 possibility that a power cord can affect the sound, good for you. Nobody is forcing to buy a Nordost power cord.
Personally, I have found differences between power cords, so I will keep using the ones that improve the sound in my system. If at some point, measurements prove that what I am hearing is true then I would have spent my money wisely. If there is no proof (ever) that power cords can affect the sound, I still don't care as it allowed me (for whatever reason) to enjoy my system even more. The way, I see things I am aware of the risks of being "fooled" but I consider that the outcome in both cases is a win situation for me.


Back to the topic of measuring the effect of power cords, if someone wants to do the measurement, better do them right.

- Let's suppose that I am wrong, then we would have used over speced equipment for the test but we still would have good results.

- Let's suppose that you are wrong, measuring a simple sine wave to incorrect results.

 

Even if you don't agree with what I subjectively hear, the proper test conditions I suggested remain right.

 

Anyway, I have said enough on the subject. If people wish to discuss further whether it is possible or not that power cords affect the sound (other than by subjective listening), it is probably better to move the discussion to the sound science forum

 
You made some interesting points... 
So there is no proper way to measure the performance of a power cable, right?  So do the manufacturers know what they're doing, or are they just putting fancy parts with fancy advertising and a fancy price tag?
How do we know a $2 monoprice power cable isn't -better- than a more expensive cable?
How do you know that shielding is better than no shielding, silver better than copper, copper better than brass, rhodium better than nickel, coconuts and tourmaline better than nothing? 
 
Yes, people believed that the earth was flat, because that was what they perceived and made the most sense.
Scientists; physicists, astronomers.... aristotle, galileo, copernicus, and dozens other were the one who brought theories and proofs to the table.  Audiophiles aren't bringing any sort of proof as of yet.  - "this is what I hear(perceive) so it must be true, despite what anyone else says"
Scientists are still trying to explain why we perceive something different than the reality, but are met with deaf ears.  
 
You also brought up that nordost study.  The opinion that the study seems to be heavily flawed w/o much credibility is besides the point.  You said we should keep an open mind, but how can you put faith in that single study when you turn a blind eye to hundreds of other ones that have been trying to prove the opposite? 
 
I appreciate what you're trying to do here, I really do..  but you seem to be trying to prove something by completely ignoring other relevant facts.

 

[BIG POPPA]

To me proof that power cables work on my rig is the smile I have listening to music. Anymore than that is a headache.

 

[haloxt]

JamesL, how many attempts in the past have been done to measure differences primarily in the time domain? And can you tell us what's so flawed about what nordost and acuity are doing?