My attempt to compare an Outlaw 7500 and a Parasound A51

[Irvrobinson]

FMW, I am not incensed at all and I do know what negative points are.
I centainly did not give you any knowingly.

- Rich

And, FWIW, fmw, I did not give you any negative reputation points either. I hate it when a certain someone does that to me.

 

[PENG]

You've nailed exactly how I feel about it. We're going around in circles only because we're both stubbornly convinced we are correct.

And you thought I was difficult to be agreeable, glad you admitted to being stubborn..

 

[mtrycrafts]

... Just like listening to different types of paint drying.
... Why is blind testing only questioned by some in audio?

You mean you don't listen to paint drying?
When someone doesn't like the answers, they object to the test resuts and the test itself. Easy way out instead of changing one's mind.

Ah yes, the other DBT worshipper, mtycrafts. Just for starters, you need to improve your reading skills, or at least your comprehension skills when someone says your idol is flawed. What I said very specifically was that using listening tests, sighted or blind, to detect subtle differences between audio system components is flawed, because of the nature of hearing and auditory memory, and the fact that one is measuring human perception, not an observable phenomenon. A DBT for determining if your pimples go away is a different testing problem. The key word in my concern is subtle, and I advocated focusing on measurements for determining relative merit. I've participated in blind listening tests, I've talked to others who participated in blind listening tests, and the low quality of the answers, how many were just guesses versus definitive were always so low, that I simply disregard them, and that isn't total nonsense.

By the way, DBT comparison tests are not used for the detecting the thresholds of hearing.

Actually, I read your post carefully and know you included both tests. Unfortunately Journals don't include the latter( sighted testing) so I didn't bother to comment.

As to subtle difference, that is absolutely the reason to use blinded testing to discover the smallest difference possible.
I guess Florentine didn't write the paper on JND thresholds of detection or is that not the threshold of hearing? I could be confused.

 

[mtrycrafts]

... Imagine comparing a short musical passage to the same passage with various amounts of pink noise added to it. Listeners would hear music + 0%, 5%, 10%, 15%, 20%, etc. (I'm just spit balling here, I haven't done this.) The tester could then determine what level of added pink noise is readily heard by listeners, and this would be the lower limit of detection. Remember that it may very well be that half the listeners comparing music vs. music + 0% pink noise might report hearing differences. So the tester has to learn what level of added pink noise can be heard by significantly more than half the listeners. Only after doing this, can a tester conclude that differences in sound from two amplifiers is or isn't detectable. That's what I mean by a properly designed listening test.

Others beside what Peng named have done this with distortion audibility. Level matching is at .1 dB for a good reason as it is below the threshold of detecting level differences with very sensitive test tones; certainly this is well below detection with speech, music, etc. I bet if someone can detect that, the level will be .05 or .01

That makes sense to me and by the way Bob Carver, Julian Hirsch and others found out 0.15% crossover distortion was detectable if a single tone is used, with more and for complex musical material, the number increased, such as 6% for complex musical material. So much for the class A thing..

Why is sub testing at 10% distortion? Because it is not audible in that band and some is hard to detect at 100% from what I have read.

 

[RichB]

Problem solved.

I just asked my wife if she thinks amps sound differently.
She said yes.

If that does not clinch it, I will be forced to ask the owl.

[video=youtube;Jhjb4P_jnKk]http://www.youtube.com/watch?v=Jhjb4P_jnKk[/video]

- Rich

 

[PENG]

Problem solved.

I just asked my wife if she thinks amps sound differently.
She said yes.

If that does not clinch it, I will be forced to ask the owl.

[video=youtube;Jhjb4P_jnKk]http://www.youtube.com/watch?v=Jhjb4P_jnKk[/video]

- Rich

That's fair, and lucky you, now tell her you need to buy a pure class A high power amp (you know Krell has those) because it will sound more different.