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Cable

MRC_Hans said:
But now Get seems to insist on his own gear for fear of rigging the other way around. Both would be avoided by using gear from an independent source.

Hans
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It could all be avoided by the age-old trick: The simple and informal self-test. Feared and shunned by prospective challengers for decades for some reason. :p
 
MRC_Hans said:
But now Get seems to insist on his own gear for fear of rigging the other way around. Both would be avoided by using gear from an independent source.

Hans
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Get seemed to be somewhat agreeable to that idea earlier in the thread. There are practical issues like buying (and then returning) a new system. I also don't know that the skeptical group in Belgium would insist on such a thing. I was just trying to think like a skeptical testing group to warn Get about obstacles that might have to be overcome.

Ward
 
Get said:
I haven't done blind tests, but the differences are so great most of the time that I don't need that reassurance.
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Seriously, get a friend to help you with a blinded and randomised test. Listen to something 20 times, with it randomly (not just swapping each time) either going via the cheap or expensive cable, and see how many you can get right.

"The first principle is that you must not fool yourself - and you are the easiest person to fool." - Richard Feynman

You will always tend to "hear" what you expect to hear.
 
Mojo said:
Seriously, get a friend to help you with a blinded and randomised test. Listen to something 20 times, with it randomly (not just swapping each time) either going via the cheap or expensive cable, and see how many you can get right.

"The first principle is that you must not fool yourself - and you are the easiest person to fool." - Richard Feynman

You will always tend to "hear" what you expect to hear.
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Protocol:

Set up the gear, so your helper can swap the cables. Put up a screen so you can't see your helper or what he/she is doing.

Label you cables A and B.

Make two lists, with three columns. One for you, one for your helper.
No A B
1
2
3
.
.
.
20

Take the same piece of music (or whatever).

Now, your helper rolls a dice, and if it is even connects cabel A, if uneven cable B, marks his/her list A or B as appropriate, calls out "Number one", and starts the music. When you have decided which cable you are hearing, mark your list accordingly, and say "Done".

You helper now disconnects the cable, rolls the dice, etc. till all 20 tests are done.

Now you compare your lists. Count the right and wrong.

10 right is random chance
11 right is 25% random chance
12 right is 12.5% random chance

etc...

If you get better than 15 right, do the test again. If you still get better than 15 right, apply for the MDC.

Hans
 
MRC_Hans said:
Protocol:

Set up the gear, so your helper can swap the cables. Put up a screen so you can't see your helper or what he/she is doing.

Label you cables A and B.

Make two lists, with three columns. One for you, one for your helper.
No A B
1
2
3
.
.
.
20

Take the same piece of music (or whatever).

Now, your helper rolls a dice, and if it is even connects cabel A, if uneven cable B, marks his/her list A or B as appropriate, calls out "Number one", and starts the music. When you have decided which cable you are hearing, mark your list accordingly, and say "Done".

You helper now disconnects the cable, rolls the dice, etc. till all 20 tests are done.

Now you compare your lists. Count the right and wrong.

10 right is random chance
11 right is 25% random chance
12 right is 12.5% random chance

etc...

If you get better than 15 right, do the test again. If you still get better than 15 right, apply for the MDC.
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Or better than 15 wrong. If he can get it wrong significantly more than half the time, he could still apply on that basis.
 
Also, turn all power off between swaps: there could be some artifact on the connector that gives some kind of telltale buzz or click upon connect.

ETA: Unless you're using an A/B switch - though that might not be a good idea, since the wires from there could be blamed for some testing failures.
 
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Call me cynical, but i think the op is one of those " i found a flaw in the MDC" applicants.

Once the concept of not using his system ( which would be a priority. ) was brought up he seems to have quickly went away.

I tend to distinguish these people by lack of information on the challenge, ( usually they hear about it from a friend and do not look beyond what they think they can beat. In this case " tell the difference between two cables.") , lack of interest in setting up a proper trial ( differentiated from the deluded by the fact they usually will quibble at length. While these folks tend to have their "challenge breaker" setup already in mind and if its not used , they know they won't win. ) , and general " just stumbled into here" nature.

Can't blame a person for trying. But the mdc is designed to weed out people who think they have found a flaw. I would suggest, to anyone who thinks they have, don't waste the posts. Your trick will be thwarted, and more than likely before you even apply.
 
Blue Mountain said:
I'd recommend an unblinded test first, to determine the difference between the A and the B cables that you believe you should be listening for.
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Which is why the right test method is an ABX test. A and B are always "cable A" and "cable B". The listener ALWAYS has the reference to knowing exactly which is A and which is B, and never has to wonder or doubt this.

All the listener has to do is to identify 'X', presented in a blind fashion, directly.
 
Blue Mountain said:
I'd recommend an unblinded test first, to determine the difference between the A and the B cables that you believe you should be listening for.
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This is an acceptable step, but not part of the test.

Hans
 
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jj said:
Which is why the right test method is an ABX test. A and B are always "cable A" and "cable B". The listener ALWAYS has the reference to knowing exactly which is A and which is B, and never has to wonder or doubt this.

All the listener has to do is to identify 'X', presented in a blind fashion, directly.
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I'm not sure I understand what you mean. What is cable X? There are only two cables.

Hans
 
MRC_Hans said:
I'm not sure I understand what you mean. What is cable X? There are only two cables.

Hans
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The listener listens to three recordings; one with cable A, one with cable B and one with either cable A or B (selected using randomised double blind means). The third cable is cable X, the listener needs to decided if cable X was cable A or B.
 
brodski said:
The listener listens to three recordings; one with cable A, one with cable B and one with either cable A or B (selected using randomised double blind means). The third cable is cable X, the listener needs to decided if cable X was cable A or B.
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No, that is not a good method. It gives a 50/50 chance of guessing right.

The listener should be tasked with discering which cable sounds 'best', and this should conicide with the 'right' cable a sufficient number of times, in order to rule out coincidence.

Hans
 
MRC_Hans said:
No, that is not a good method. It gives a 50/50 chance of guessing right.

The listener should be tasked with discering which cable sounds 'best', and this should conicide with the 'right' cable a sufficient number of times, in order to rule out coincidence.

Hans
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How does your option not also give a 50/50 chance of guessing right?

ABX tests can be repeated often enough to rule out coincidence in the same way that AB tests can.
 
brodski said:
How does your option not also give a 50/50 chance of guessing right?

ABX tests can be repeated often enough to rule out coincidence in the same way that AB tests can.
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If you repeat the ABX test, how is it different from the protocol I suggested?

Do you suggest a reference listening every round, like A-B-X; A-B-X; ...etc?

I fail to see the purpose of that; it will only make the test take 3 times longer.

Hans
 
MRC_Hans said:
If you repeat the ABX test, how is it different from the protocol I suggested?

Do you suggest a reference listening every round, like A-B-X; A-B-X; ...etc?

I fail to see the purpose of that; it will only make the test take 3 times longer.

Hans
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To be honest you would have to ask JJ, he's the expert here.
 
MRC_Hans said:
This is an acceptable step, but not part of the test.

Hans
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While not, perhaps, necessary during a self test, this is an important step in any official challenge test. It is important for the applicant to demonstrate that he or she can do what is claimed in an unblinded test first, in order to rule out a later claim that there were confounding factors preventing success during the test.
 
MRC_Hans said:
No, that is not a good method. It gives a 50/50 chance of guessing right.

The listener should be tasked with discering which cable sounds 'best', and this should conicide with the 'right' cable a sufficient number of times, in order to rule out coincidence.

Hans
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Sorry, Hans, this is a terribly insensitive test you suggest. You're testing preference, rather than difference. If you read the literature, you'll find out that difference testing is more sensitive. If you want a sensitive test, do not test preference. It's really that simple.

As far as replication, of COURSE you have to repeat this the same number of trials you'd have to repeat an AB preference test. Duh... Why would you imagine otherwise?

But an ABX test has shown better sensitivity. That's the point.

Do I expect this cable to show up? Not unless it's got some kind of network in it, implicit or explicit, no, not a chance. I've seen a lot of cable tests, and except (as I said above) for one where a deliberately too-small speaker cable was used, everyone was inside of the 25% space, which is just random.

I have had connectors show up in a blind test, but they were, to use a simple word, defective. So, again, no shock there, yes? What's more, unplugging them and plugging them in again scraped off the oxide layer, and then they sounded the same as everything else. The joys of RCA connectors, some of the lousiest, and ubiquitous, connecters around.

Tasking the listener with determining which sounds "best" is nothing more than a way to desensitize the test. Period. If you do that, and the subject agrees, well, fine. I don't expect any results there, either, unless the cable has actual, testable, measurable electrical properties. Some do, of course, and you should be on the lookout for that. Nothing paranormal in too-small conductors, series resistors, etc.

I've even made such a cable to yank somebody's chain a long time ago. Just put a 1/8 watt, 220 ohm resistor INSIDE the barrel of the RCA connector and soldered it in series. Presto. Lowpass filter (cable capacitance).

I guess I also have to be clear, I have heard an audible difference in one other speaker cable case. An early set of "matched impedence" speaker cables that had an undogly amount of capacitance were connected to a highly acclaimed amplifier known to be marginally stable. The result was audible (crackling of burning parts), visible (smoke rising from the amp) and olfactory (PHEEEEW). I didn't touch the burning parts or try to taste them. :)
 
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