[shivohum]

From Amp challenge rules, revisions & posts.

"There is no question that all amps are not the same. ... Given the relatively small magnitude of performance differences, there is a giant step between amplifier performance and our ability to hear performance differences. ... To win the $10,000.00, the listener must pass two complete sessions of 12 comparisons. Passing the test means 24 correct responses. [in blind testing]*"

Discussion also on Decware and Harmonic Discord

The challenge apparently used to be open only for car amplifiers, but now it's open to high-end home amps too.

The threads are mostly people whining about how long-term listening results can't be accurately tracked by A/B tests that take place over only several hours, even when people claim differences between amps are absolutely astounding.

 

[Ebonyks]

I'm mainly curious about what amps are being used. For headphones, i'd think it'd be difficult to chose a choice can to be able to accurately detail the differences between amps. I highly doubt i could do a great job wearing AK-1000's.

 

[shivohum]

Ebonyks, I think you can use any amp you like subject to the following conditions:

"... The amp of choice can be compared to the same or a different amp in each session - challengers choice. We have many amplifiers in our demo inventory such as, but not limited to, Alpine, Rockford, Kicker, Phoenix Gold, Precision Power, MTX, Adcom, Kenwood, Pioneer, Sony, etc. You can pick any of them or bring your own.

7. All amps must be brand name, standard production, linear voltage amplifiers. This does not exclude high current amps. Amps can not be modified and must meet factory specs. ..."

For the amp he chooses for the comparison, I think he reserves the right to insert a resistor in series (or parallel?) with the speaker. He claims this mimics the effect of a tube transformer.

 

[Ebonyks]

IMO, i think that providing amps would make the contest more fair. Someone could easily modify their amps to cause audiable differences from eachother. As implied earlier, i think a headphone contest would be more fun though, a few more things to consiter. Just a bunch of provided, common, everyday, high end amps, and a nice set of cans to go with it.

 

[Wodgy]

The guy sponsoring the contest is a troll. If he's as good an engineer as he claims, he'll have enough of a background in statistics to understand just how impossible his test is to win, even if there are fairly major differences between amplifiers.

To win, you need 24 correct responses. A single wrong answer will kill you. Let's assume that 80% of the time you can reliably tell the difference between two amplifiers in double-blind testing. Most sane people would agree that a consistent 80% success rate would be very strong evidence that amplifiers sound different. If you take listener fatigue into account, an 80% success rate would be even more astonishing.

However, using basic statistics, the probability that you'll be wrong at least once in those 24 responses is:
1 - 0.8^24 = 99.5%

Thus, he knows he won't be giving away the money. The challenge proves nothing scientific.

 

[andrzejpw]

Wait, so this is only with speakers? What kind of speakers are these? Do they choose? Heck, if I brought a cmoy and got a blockhead on loan from headroom. . . Tyll, I'll give you $1000 if I win.

 

[shivohum]

Quote:

To win, you need 24 correct responses.

Not exactly true. That's the standard challenge, yes. But, from the rules:
Quote:

* Twelve correct responses in a row is certainly a lot of correct listening but $10,000 is also a lot of money for a few hours of easy listening. The way people describe the differences is that they are like night and day. I would certainly not have any trouble choosing between an apple and an orange 12 times in a row. When compared fairly I believe the differences in amps are much too small to audibly detect and certainly too small to pay large sums of extra money for. If I am wrong someone should be able to carefully take this test and win my money. Even if I am right, if enough people take the test eventually someone will take my money due to random chance. This is the reason for the large sample requirement. If you feel that you can easily pass this test but 12 sequences will give you "listening fatigue" I am willing to modify the requirements. Since the way it is being offered is a challenge and only my money is at risk I am willing to let a confident challenger "put his money where his ears are". If we are willing to make this a bet instead of a challenge, I am willing to drop 1 sequence for every thousand dollars put up by the challenger against my money. This would mean: ____My___________ _ _Your________Trails Required to win__ $10,000 to $0 = 12 Tries $9,000 to $1,000 = 11 Tries $8,000 to $2,000 = 10 Tries $7,000 to $3,000 = 9 Tries $6,000 to $4,000 = 8 Tries $5,000 to $5,000 = 7 Tries $4,000 to $6,000 = 6 Tries I will not do the test with less than 6 trails. It would be statistically meaningless and reduce the challenge to mere gambling

If you can't get two sequences of 6 right with a very high degree of confidence, I don't think you deserve to call the difference a large one, as so many people do.


Andrej, to answer your question regarding speaker choice:

Quote:

1. To make things easy we would prefer to use high quality home type loudspeakers for the test. If our speakers are not acceptable, the listener can provide any commercially available speaker system as long as it uses dynamic drivers. The actual measured impedance cannot exceed the rated load impedance of the amplifiers tested. If, however, the tester would like to perform the test in a car, we will use a car, however, it will have to be provided by the test subject. For practicality we will have to limit the number of amplifier channels to four or less.