Are some people seriously suggestion, that a different power cord will lower/increase the output by 2 dB?
If that really did happen, it should be no problem to reproduce the effect in a scientific environment. Cables can be measured and these measurements can be publicized (impedance and resistance). That would put a quick stop to this discussion.
But right now there is no way, a power cord can make a difference (imo).
If that really did happen, it should be no problem to reproduce the effect in a scientific environment. Cables can be measured and these measurements can be publicized (impedance and resistance). That would put a quick stop to this discussion.
But right now there is no way, a power cord can make a difference (imo).
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it seems that we agree that the presented facts (for the alledged fraud) aren´t really facts up to this point but just anecdotical description.
<snip>So take it in that context.
I´ll do so....
So at least two observers at a "technical demonstration" or "sales event" noted level differences during the demo, and of those who noted these difference at least two also measured those level differences and obtained similar results. That sounds like confirmation of a repeatable result to me. No one has come forward with contradictory observations.
Now, a wise man once said that we should not attribute to evil that which is adequately explained by incompetence, and it is conceivable that the people running the event were so incompetent that they could not control levels or do not understand the importance thereof.
Just because someone had their thumb on the scale doesn't mean the object being weighed wasn't heavier, but it does mean the test was invald and conveyed no information.
No, it does not. You claim that people come in with prejudice against cables, so they believe it was fake. That's like me taking posting a photo of a pie plate on a string and saying "A UFO flew over my house!" and people defending me and the photo because, you know, we don't want to have any biases.
Yes, the 2dB measurement is open for discussion. Wasn't there someone beside him with a similar measurement? But that's the only detail. That anyone is willing to believe the power cord made an honest, audible difference without cheating, rather than believe someone who made a measurement speaks volumes. It shows the very bias you complain about.
No, so far nobody asserted that; it was just claimed that intentionally a level difference was introduced to demonstrate a better sound quality.
But there exists up to now only anecdotical evidence for the wrongdoing.
If that were true, then the power cables would get hot as hell.
The only way that 16-18 gauge cables could produce a 2 dB insertion loss, is if the power source had a very high frequency - I'm talking megahertz - NOT 50-60 hertz.
And modern electrical distribution systems in no way, shape, or form, are capable of delivering power at such high frequency. Everything - transformers, wire, etc, is designed to work with 50-60 hz and only 50-60 hz.
In other words, the claim is a big steaming pile of horse manure.
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This is the most likely explanation. And if you talk to hi fi sales people, then you can tell that some of them actually believe their fantastic claims. In other words, they're incompetent.
Same thing, right?
As far as I'm concerned, the fact that it wasn't done in a controlled environment by competent, disinterested parties is reason enough to be very skeptical of the claim. And the fact that it doesn't add up from a technical perspective justifies summary dismissal of the claim, in my opinion.
Actually, we have drifted here. The thread is about an iffy seeming demo, and the over reaction by someone with a vested interest to an honest claim of foul. The correct response would have been to check all the facts, not demand a retraction of a carefully worded complaint, along with a threat.
It seems that we are talking past each other. I´ll quote the description i was referring to:
"One guy was from a power cable company and spent 30 minutes talking about the importance of power cords on sound systems. He did the usual things including hooking up an audio circuit to a power outlet and showing us all the incredible amount of noise on the line — noise that never gets converted into the DC power sources used in your components. This is a red herring argument.
He then demonstrated 4 different power cords ranging in price from a few dollars (a typical IEC cable like the ones included in the box) to about $17,000 for the Nordost Odin 2 Power Cable. The two cables from his company were $750 and $4000 — a mere fraction of the price of the Nordost. I brought along a reference quality microphone and portable recording device which I kept out of view as I recorded the music selections powered through the different cables. Actually, I wasn’t the only one using this method to evaluate the presenter’s claims. As I looked to the right, another attendee was using the SPL meter app on his smartphone to do a less rigorous version of the same test! Apparently, I’m not the only skeptic in the audiophile world. Despite the presenter’s insistence that the sound was “much smoother, less harsh, and had a much lower noise floor” with the expensive power cords, my measurements showed otherwise.
I loaded the audio into Adobe Audition and carefully edited each music section to identical lengths. Then I measured the amplitude and plotted the spectra of each. As if by magic, the IEC power cord measured 2.5 dB SPL lower than the others. The most expensive cable — the Nordost Odin 2 — was louder by a substantial amount than the Dragon and Thunder cables the competitors provided. When I asked the other person measuring the SPL in the room, he concurred with me. “I saw about 2 dB difference,” he whispered. I found it curious that the presenter had to kneel down in front of the rig each time after the cables had been switched. Maybe he was adjusting the level of the preamplifier, I can’t say for sure. But I can say with certainly that power cords do not cause a 2-3 dB increase in amplitude and we don’t want them to!"
(Source: High-End Mischief — Again! | Real HD-Audio) (Bold set by me now)
"One guy was from a power cable company and spent 30 minutes talking about the importance of power cords on sound systems. He did the usual things including hooking up an audio circuit to a power outlet and showing us all the incredible amount of noise on the line — noise that never gets converted into the DC power sources used in your components. This is a red herring argument.
He then demonstrated 4 different power cords ranging in price from a few dollars (a typical IEC cable like the ones included in the box) to about $17,000 for the Nordost Odin 2 Power Cable. The two cables from his company were $750 and $4000 — a mere fraction of the price of the Nordost. I brought along a reference quality microphone and portable recording device which I kept out of view as I recorded the music selections powered through the different cables. Actually, I wasn’t the only one using this method to evaluate the presenter’s claims. As I looked to the right, another attendee was using the SPL meter app on his smartphone to do a less rigorous version of the same test! Apparently, I’m not the only skeptic in the audiophile world. Despite the presenter’s insistence that the sound was “much smoother, less harsh, and had a much lower noise floor” with the expensive power cords, my measurements showed otherwise.
I loaded the audio into Adobe Audition and carefully edited each music section to identical lengths. Then I measured the amplitude and plotted the spectra of each. As if by magic, the IEC power cord measured 2.5 dB SPL lower than the others. The most expensive cable — the Nordost Odin 2 — was louder by a substantial amount than the Dragon and Thunder cables the competitors provided. When I asked the other person measuring the SPL in the room, he concurred with me. “I saw about 2 dB difference,” he whispered. I found it curious that the presenter had to kneel down in front of the rig each time after the cables had been switched. Maybe he was adjusting the level of the preamplifier, I can’t say for sure. But I can say with certainly that power cords do not cause a 2-3 dB increase in amplitude and we don’t want them to!"
(Source: High-End Mischief — Again! | Real HD-Audio) (Bold set by me now)
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So, the gain element of the amplifier doesn't run on 120VAC directly. They have power supplies that power DC rails of some voltage. There is step-down, rectification, and sometimes regulation, usually with a ton of filtering. How does changing the AC path for 6 feet or so between the wall outlet and the supply input change the amplitude of the audio produced?
For example, if I had an amplifier that had a straight +20dB gain (looking at you, @Tomchr), would I see +2dB additional gain by swapping out the power cord?
Maybe somebody can explain that part to me.
For example, if I had an amplifier that had a straight +20dB gain (looking at you, @Tomchr), would I see +2dB additional gain by swapping out the power cord?
Maybe somebody can explain that part to me.
It doesn't change the level 2db. You've missed the whole gist of the discussion.
The Audioquest guy conducting the demonstration altered the volume control setting by 2db when making the power cord change.
The scenario here is not about power cords, but rather a fraudulently conducted comparison.
Dave.
Not sure what kind of scientist you are, hopefully not an amplifier scientist. The concept that a 2db loss in acoustic pressure can be directly linked to a 2db loss in the AC voltage is wrong on so many levels... Not that it surprises me. Not at all. What surprises me more is that none of the technically proficient participants in this discussion corrected your obvious wrongness. Now, why would that be?
I didn't miss anything. I've been in several discussions with Mark about these and other issues. I'm simply pointing out that there is no mechanism that I can see where a change in an AC power cord could affect the audio output level by 2dB, and was looking for any mechanism besides alleged fraud for the effect to even occur.
There isn't any mechanism.
Even if we assumed that power cord X dropped the line-voltage by some minor amount, it still wouldn't change the voltage gain of the amplifier.
I'm not sure what sort of explanation would be satisfactory here.
Dave.
Jakob2, you are so right about what people do, and it may be a good way to get people's attention to say it is amazing, but really it isn't amazing at all.
It is how people have fun posting on internet forums, particularly when the people are by in large not trained scientists. Rather people are full of biases that operate constantly, including all the System 1, System 2 stuff, the ease of seeing faults in others, yet the blindness to one's own faults, etc., etc.
I wish you the best of luck, but you are fighting hundreds of thousands of years of evolution.
NO, that is not my point. It was more, that people are just believing in the presented "evidence" - which in fact is up to now purely anecdotical - because it fits their prior beliefs.
But, there is good reason not to accept it because it is _not_ factual evidence. Again, up to this point, there might be enough additional information not yet published to provide corrobation/real evidence for the alleged wrongdoing.
As said above it think we were talking about different stories and i´ve posted the one i was referring to.
You´ll notice that it´s not only one detail - it starts with the first bold statement which is simply wrong - but more the details overall.
As said before Mark Waldrep describes a measured level difference of 2.5 dB between "ordinary iec cord" and "the others" and the Nordost was substantially louder than the two others (from the cable guy) .
I´ll try to avoid believing in such things.
Do you know what audio circuit was used in the demonstration? Or do you know what level of HF was transmitted on the mains grid in the venue?
Does anybody of us know if a real difference was percepted by anyone?
As said before, maybe i missed some facts (so please it would be nice if somebody post it) but up to now we neither know what was really measured nor what was really hear.
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You miss the point, for this thread - it doesn't matter! This is about the unreasonable reaction to a suspicion of "match fixing". I'm sure Mark Waldrep would be happy if proved wrong, or if a genuine attempt to find facts was initiated. But - no one even tried, Bob Levi just threw all the toys out the pram.
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