Re: Re: Re: Re: Re: Re: Re: Re: Can a power cord affect sound quality??
Konnichiwa,
I am sure that there is some logic in your statement, but it escapes me. I do not remember writing the above or anything to the effect.
I did simply ask if the experimenter had first attemptet to validate his experiment by returning some "positives" in his experiment using KNOWN AUDIBLE stimuli, before proceeding towards attempting to establis the audibility of phenomenae whose audibility is in question, using a method that has a propensity to return "null" results UNLESS reliable detection is present.
I suggested to you some stimuli I'd consider to be "generally known to audible" to save myself digging out references.
I have demonstrated twice at DB Tests that the setup (not just room/equipment but also others) was such that even the most basic audible stimuli where not detected with sufficient reliability to return a "positive", casting a large question on the specific test setup when used to validate the audibility of unknown and small stimuli (such as digital watermarking).
DB Tests showing audible differences where first published in the 1980's in the JAES. There is hardly anything new in my data.
The fact that cables with identical electrical parameters do not neccesarily behave idetentical is well understood outside oudio, again, nothing new. It is only that some audiotes seem to want keep their heads in the sand....
No basic assumption of the science called statistics is faulty, rather the basic assumptions made by the experimenters in the application thereof.
The use of a very low value of signifcance (.05) if the number of samples in the test population is insufficiently large for the application of such a level of significance UNLESS one DELIBERATLY wishes to prejeduice the test to return a "null" result. Examples of DB/ABX Tests with small sample sizes (< several 100) and a significance level of .05 abound in the usual circles. Such tests simply cannot be taken with any seriousness if the reliable detection of small differences is concerned.
Sayonara
Konnichiwa,
fcserei said:
I am sure that there is some logic in your statement, but it escapes me. I do not remember writing the above or anything to the effect.
I did simply ask if the experimenter had first attemptet to validate his experiment by returning some "positives" in his experiment using KNOWN AUDIBLE stimuli, before proceeding towards attempting to establis the audibility of phenomenae whose audibility is in question, using a method that has a propensity to return "null" results UNLESS reliable detection is present.
I suggested to you some stimuli I'd consider to be "generally known to audible" to save myself digging out references.
I have demonstrated twice at DB Tests that the setup (not just room/equipment but also others) was such that even the most basic audible stimuli where not detected with sufficient reliability to return a "positive", casting a large question on the specific test setup when used to validate the audibility of unknown and small stimuli (such as digital watermarking).
fcserei said:
DB Tests showing audible differences where first published in the 1980's in the JAES. There is hardly anything new in my data.
fcserei said:
The fact that cables with identical electrical parameters do not neccesarily behave idetentical is well understood outside oudio, again, nothing new. It is only that some audiotes seem to want keep their heads in the sand....
Rob M said:
No basic assumption of the science called statistics is faulty, rather the basic assumptions made by the experimenters in the application thereof.
The use of a very low value of signifcance (.05) if the number of samples in the test population is insufficiently large for the application of such a level of significance UNLESS one DELIBERATLY wishes to prejeduice the test to return a "null" result. Examples of DB/ABX Tests with small sample sizes (< several 100) and a significance level of .05 abound in the usual circles. Such tests simply cannot be taken with any seriousness if the reliable detection of small differences is concerned.
Sayonara
Re: I should know better ....
Hmmmm...ok thennn
If I take a thousand turns of #10 magnet wire, form them into a solenoid 1 foot across, then pump 100 amps rms at 60 hz into it..then put this coil with the pc/pc/ic loop, the smoke and fire that results because of the generated loop current causes all the loop conductors to fry in the ic and pc's.....is ...well..hmmmm...inaudible...
If I did that while the system was on, I'd clip the amp output...yes, my example is extreme, but 100 amp sines are not that far from what is going in that system..a 5 amp draw from a power amp is in the form of haversine pulses, starting at 180 hz. Loop inducted voltages are proportional to the frequency..
And, even though the hot/neutral of the amp pc is twisted, is it the same pitch as the pre cord? Meaning the ground of the pre cord can pick up integral non zero flux....
It would appear that it is not possible to focus on the actual electrical details on this forum..
Oh well, I tried..toodles..
Cheers, John
PS...how many of you have measured the voltage at the socket between the neutral and ground? I just measured between half a volt and 250 milli..
Anybody care to guess what is causing it?? Don't forget, they are tied together back at the panel..and saying it is loop pickup from the current being drawn by some other item sharing the line is no fair..you peeked at my post..
mefinnis said:
So ..... to the question ...... can a PC significantly affect sound?
1. Let's assume what reaches your house is perfect sine-wave, in phase power (highly unlikely actually, but then).
2. Let's forget we are going to rectify this to DC.
3. From your meter box you have maybe 15-20 meters of standard house-hold electrical cable. This has all the faults "claimed" in standard power cords. I expect the vast majority have little knowledge of what is actually in their ceilings.
4. On the end of this 10+m "low audio quality" cable we are going to place 1-2m of either standard power cord, or 0.5-1.0m of "audiophile power cable".
Hmmmmm .....
All logic would suggest that any real difference here is extraordinarily small.
Hmmmm...ok thennn
If I take a thousand turns of #10 magnet wire, form them into a solenoid 1 foot across, then pump 100 amps rms at 60 hz into it..then put this coil with the pc/pc/ic loop, the smoke and fire that results because of the generated loop current causes all the loop conductors to fry in the ic and pc's.....is ...well..hmmmm...inaudible...
If I did that while the system was on, I'd clip the amp output...yes, my example is extreme, but 100 amp sines are not that far from what is going in that system..a 5 amp draw from a power amp is in the form of haversine pulses, starting at 180 hz. Loop inducted voltages are proportional to the frequency..
And, even though the hot/neutral of the amp pc is twisted, is it the same pitch as the pre cord? Meaning the ground of the pre cord can pick up integral non zero flux....
It would appear that it is not possible to focus on the actual electrical details on this forum..
Oh well, I tried..toodles..
Cheers, John
PS...how many of you have measured the voltage at the socket between the neutral and ground? I just measured between half a volt and 250 milli..
Anybody care to guess what is causing it?? Don't forget, they are tied together back at the panel..and saying it is loop pickup from the current being drawn by some other item sharing the line is no fair..you peeked at my post..
Interpreting results
Sure they can be taken seriously. They fail to show there is a difference. A lot of those failed tests taken together suggest that if there is a difference, it is very small. Where's the faulty assumption in that?
How big a difference do you think there is? How often do you think you would be able to "pass" an ABX test of one of these differences? 55% of the time? 65%? 75%?
Kuei Yang Wang said:
Sure they can be taken seriously. They fail to show there is a difference. A lot of those failed tests taken together suggest that if there is a difference, it is very small. Where's the faulty assumption in that?
How big a difference do you think there is? How often do you think you would be able to "pass" an ABX test of one of these differences? 55% of the time? 65%? 75%?
Re: Interpreting results
Konnichiwa,
The ones I quoted as my "personal calibration"? If the test setup is correct I'd have at least 8/10 on all, unless I was having a night out with loads of drinkies the night before. And if I didn't, I'd suggest the setup is insufficiently revealing.
Sayonara
Konnichiwa,
Rob M said:
The ones I quoted as my "personal calibration"? If the test setup is correct I'd have at least 8/10 on all, unless I was having a night out with loads of drinkies the night before. And if I didn't, I'd suggest the setup is insufficiently revealing.
Sayonara
Re: Re: Interpreting results
With a sample size of 50, you'd have a 0.25% chance of incorrectly failing to find an effect that strong. That doesn't seem to me like deliberately rigging the test for failure.
As I posted on another thread, here are some nifty calculators for figuring out the sample size necessary to reliably find a given effect:
http://calculators.stat.ucla.edu/
Look under "Power calculators".
Kuei Yang Wang said:
With a sample size of 50, you'd have a 0.25% chance of incorrectly failing to find an effect that strong. That doesn't seem to me like deliberately rigging the test for failure.
As I posted on another thread, here are some nifty calculators for figuring out the sample size necessary to reliably find a given effect:
http://calculators.stat.ucla.edu/
Look under "Power calculators".
Re: Re: can a power cord influence the sound
I did. And it sounds MUCH better!
se
dutch diy said:A definit Yes:
Try removing it
I did. And it sounds MUCH better!
An externally hosted image should be here but it was not working when we last tested it.
se
How power chords affect haromonics:
From this web site:
http://tranchant.plus.com/guitar/power-chords
From this web site:
http://tranchant.plus.com/guitar/power-chords
Re: Re: Re: I should know better ....
But it is in my wiring...it's not conduit
Plus, as I hinted...it is changing tremendously...actually, I didn't really say that at all..just re-looked at my post..
If it were simply non equidistant capacitive coupling, it would remain pretty constant..mine depends heavily on other pieces of equipment in the local area. Hmmmm...I wonder if other equipment contactors alter the capacitive ratio?...I think I'll load the neutral/ground with some arbitrary resistor, see if it's a low impedance pickup due to loops, or high impedance due to capacitance..
Cheers, John
Steve Eddy said:
But it is in my wiring...it's not conduit
Plus, as I hinted...it is changing tremendously...actually, I didn't really say that at all..just re-looked at my post..
If it were simply non equidistant capacitive coupling, it would remain pretty constant..mine depends heavily on other pieces of equipment in the local area. Hmmmm...I wonder if other equipment contactors alter the capacitive ratio?...I think I'll load the neutral/ground with some arbitrary resistor, see if it's a low impedance pickup due to loops, or high impedance due to capacitance..
Cheers, John
Re: Re: Re: Re: I should know better ....
What's conduit to do with it?
Ah, I thought you put that out as a general question rather than a specific situation.
Well any leakage current on the safety ground lead due to equipment on the line will have a voltage drop across it due to wire resistance which would show up if you measure between neutral and safety ground.
se
sully said:
What's conduit to do with it?
Ah, I thought you put that out as a general question rather than a specific situation.
Well any leakage current on the safety ground lead due to equipment on the line will have a voltage drop across it due to wire resistance which would show up if you measure between neutral and safety ground.
se
Re: Re: Re: Re: Re: I should know better ....
Conduit you ask?? glad you did..
In conduit, the relation between conductors and ground may physically be different ....waiddddaminute...
Ground is a #12 or #14 to the neutral..total round trip resistance...what, .1 ohm...???
To get half a volt drop would require capacitive currents in the 2 to 5 amp range..that ain't gonna happen through the insulation..
Any equipment leakage is gonna be in the 50 microamp range (general spec for 5Kv hipot). Again, the drop will not be measureable at the outlet..
Thanks Steve..you at least support the Geek part of the threads..
And the bad pun part...quite well, I must add..
Cheers, John
Steve Eddy said:
Conduit you ask?? glad you did..
In conduit, the relation between conductors and ground may physically be different ....waiddddaminute...
Ground is a #12 or #14 to the neutral..total round trip resistance...what, .1 ohm...???
To get half a volt drop would require capacitive currents in the 2 to 5 amp range..that ain't gonna happen through the insulation..
Any equipment leakage is gonna be in the 50 microamp range (general spec for 5Kv hipot). Again, the drop will not be measureable at the outlet..
Thanks Steve..you at least support the Geek part of the threads..
And the bad pun part...quite well, I must add..
Cheers, John
li_gangyi said:
I build 5 to 15 tesla superconducting magnets with Lts(niobium titanium) superconductors...niobium tin, and HTS (yibco and bisco).
I design 11 axis computer controlled ultrasonic wiring machines..
I build and test 6000 amp cryogenic diodes as quench protection devices...and test superconducting accelerator magnets at 4.5 Kelvin, in liquid helium..
Why would I debate ""that weather cyro treated tubes or mains sockets sound better??""
To what end have you posted this particular crap???
I use maxwell's equations daily...work with entities you have no clue about..in fact, most engineers on this planet have no clue about...and you ask this garbage????
I ask only for intelligent discussion...and...what do you provide?
Cheers, John
li_gangyi said:
Li..my apologies...
But if I wanted to deal in BS...I could find quite a few forums that deal in that particular type of garbage..
If you have anything constructive to add to what I have posted, please do so..I would love to read it..
Otherwise...what in the name of sam hill are you doing here???
I would be more than willing to answer your questions regarding the hypothesis I have provided..I of course assume, that you are interested..Am I wrong in my assumption?? Do I have to more fully explain the hypothesis I have provided???
Cheers, John
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