Power Cable for a Bass Amp Question

[Bob Lee (QSC)]

Originally posted by MKS
As a qualified statistician I would be very pleased to help design a blinded test of these cables.

Unfortunately it can't be double blind unless you can make two different power cables look identical. Double blind means that the person hearing the results and the person switching the cables does not know which cable is which.

My thought would be that you need to have two or more testers / listeners who will listen to and rate the results. You ought to use one standard test rig with an identical signal going through the rig each time - this could either be a looped signal or a standard test signal. Presumably you would have a some kind of standard signal that covers a variety of frequencies... Then you need to listen to this test signal a number of times (10+?) while switching the cables *randomly* for each listening but making sure that each cable gets used the same number of times (viz. Cheap cable 5 times, Tara Labs cable 5 times). The person switching the cable should not be one of the listeners and if possible should not be visible by the listeners (so that they don't know if that person "switches" between one cable and the same one. i.e. that the same cable is used in two adjacent tests). The listeners decide whether what they are hearing is the Tara Labs cable or the cheaper cable. They don't *have* to rate what they like about the sound etc. Simply A or B will be enough.

Once the ratings have been completed it is a really simple statistical test to test if the listeners are guessing which cable is which and if they can hear a difference.

If you would like to take more in-depth measurements or qualitative measurements, then I'd be happy to provide input to the design and analysis.

Hi Mike,

We have QSC ABX comparators at our disposal, and they track results for up to 25 trials in a session.

For the sake of completeness, I would plan also to do "same-different" tests. Tom Nousaine has used those for situations where ABX testing was not practical.

You are correct that it first has to be established either that there is an audible difference, or that no evidence exists that there is. Only if an audible difference can actually be demonstrated can anyone truthfully judge whether one sounds "better" than the other.

A major fallacy of most comparative listening "tests" is the a priori assumption that the change will cause an audible difference, leading to an abundance of false positives. That's why the stories of audio "experts" claiming to hear great differences when they think the speaker cables have been changed, but in fact the cables haven't been, ring so true with anyone who's been involved with comparative listening tests.

 

[PhatBasstard]

Originally posted by rcz
...and also while drunk. i think that is a powerful mitigator of circumstances.

robb.

You, like too many TBers, assume too much.

 

[robb.]

fair enough.

robb.

 

[Pajama_Bottoms]

Originally posted by natrab
Ladies and Gentlemen, this is Chewbacca:

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Chewbacca is a giant hairy wookie. However, Chewbacca lives on the planet Endor. Now that does NOT make sense.

Why would a six foot tall wookie like Chewbacca want to live on a planet full of a bunch of little Ewoks?

THAT DOES NOT MAKE SENSE.

Does this cable make you sound better? I don't know, but IT DOES NOT MAKE SENSE.

Ladies and Gentlemen if Chewbacca is a six foot tall wookie who lives on Endor and none of this makes sense, then you have to buy this Tara cable because you don't know what you may be missing!

Silly, Chewbacca is from Kashykk, not Endor! This just makes your whole logic seem deeply flawed!

Sorry, my nerd side kicked in there

 

[Mark Reccord]

Originally posted by SMASH
Audio Snake Oil

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Yup. I'd tend to agree. I notice that my posts concerning the DBTs I was involved in get ignored by the proponents of the esoteric cables. Wonder why?

 

[NJL]

i guess no tests yet?

 

[pkr2]

Originally posted by NJL
i guess no tests yet?

Anyone really believe that Tara Labs will really send cables for an honest test?

How about the tooth fairy and santa claus?

If they follow through with thier promise to send cables,I will be almost as astounded as I would if the tests came out in thier favor.

Thier ammended offer will include a blind test set up at thier convenience using thier test subjects. As I've said before, Tara Labs will never submit to such a test even if Long Ly were willing. They have WAY too much to lose.

how long since the challenge was accepted? well over a week and still no cables in hand. They must be delivering them by santa claus.

I am assuming that the cables haven't arrived. Is my assumption correct, Tim?

Harrell S.

 

[NJL]

Bob,

have you talked to any of those guys yet?

 

[robb.]

actually, it was my understanding that the testing is waiting on Pat Quilter (the "Q" in "QSC") to free up some time to attend the listening party.

if you have been keeping up with the posting, you'd know this to be the case. thanks for the pre-christmas anger, though. it brightened my day.

robb.

 

[NJL]

Originally posted by rcz
actually, it was my understanding that the testing is waiting on Pat Quilter (the "Q" in "QSC") to free up some time to attend the listening party.

if you have been keeping up with the posting, you'd know this to be the case. thanks for the pre-christmas anger, though. it brightened my day.

robb.

is this directed towards me?

 

[robb.]

Originally posted by NJL
is this directed towards me?

no. check it out:

posted by pkr2
how long since the challenge was accepted? well over a week and still no cables in hand. They must be delivering them by santa claus.

I am assuming that the cables haven't arrived. Is my assumption correct, Tim?

Harrell S.

happy holidays!

robb.

 

[pkr2]

And you were offended by exactly what?

If you had been keeping up with the posts you would know that I was talking to Tim about the cables that were supposed to be being shipped to him.

I'm glad to have brightened your day!

Harrell S.

 

[ModulusFan]

Doh, sorry for the late reply, I've had a ton of things to take care of this past week. Long contacted me the other day, and said cables would be in their way at the end of this week, or Monday at the latest. I'll without a doubt post here on their arrival, and announce the testers, and we can come up with a roadmap and schedule for their tour.

 

[HeavyDuty]

Originally posted by rockindoc
Threads usually die when I post.

Let's try it again, then.



Serously, I anxiously await the test results. I sincerely doubt there will be any difference, but I'll keep an open mind...