In Reply to: Question RE: Atkinson - DBT/Absolute Signal Polarity posted by bjh on December 16, 2007 at 13:30:27:
Trying to follow this is getting confusing. I'll try to shed some light on it, but I'm still not able to completely unravel the situation. Here's what I have so far.
I was able to dig up one of the references cited in the Stereophile article mentioned by bjh above. That reference is:
"On the Audibility of Midrange Phase Distortion in Audio Systems" (with John Vanderkooy and Mark Pocock), JAES, Vol.30 No.9, September 1982
I don't have access to the BAS publication referenced in the Stereophile article, only AES articles.
Part of the confusion is that the Lipshitz AES article is concerned with the audibility of the nonlinear phase response caused by all-pass filters such as what result when the high-pass and low-pass outputs of a Linkwitz-Riley loudspeaker crossover are summed. Absolute polarity is not the subject at all, but it is mentioned briefly in passing. Here is what I believe to be the relevant quote from the Lipshitz paper:
"The authors have demonstrated the two-tone experiment described above to numerous people on different systems. No one has ever failed to hear the timbral change with phase, and discern the polarity reversal on this signal with unvarying accuracy. Indeed, in a double-blind demonstration to eleven members of the SMWTMS audio group [13], the accuracy score was 100% on the summed 200-Hz and 400-Hz tones over loudspeakers, and overall, including musical excerpts, the results on the audibility of the polarity inversion of both loudspeaker channels were 84 correct responses out of 137, this representing confidence of more than 99% in the thesis that acoustic polarity reversal is audible."
So it can be seen that this test was apparently a mixture of musical excerpts and the test signal, not just music alone. The reference [13] is as follows:
B. F. Muller, "Third World: The Scientific Subjectivists," Audio Amateur, vol. 11, p. 64 (1980 Jan.).
I'd love to get this article if anyone has it. It's not at all clear to me whether Lipshitz had anything at all to do with the tests in that article, or if he's just referencing somebody else's results. Some other questions arise from this also, namely, "What fraction of the tested samples were 'musical excerpts'?", and "How did the individual scores on music and test tones break down?".
It looks like those questions can be answered by the info on the ABX site . These are broken down as follows:
Test signal: 24 / 24 = 100%
Music: 60 / 113 = 53%
These numbers match up with Lipshitz's reference of 137 total trials.
So this brings us to the statement made by John Atkinson in the referenced article, which I quote below.
"Work by Stanley Lipshitz in the late '70s (footnote 9), using carefully organized double-blind testing, confirmed that a reversal of absolute signal polarity will be subtly audible on music to a 99% confidence limit!" (Italics by JA).
Footnote 9 is as follows:
Footnote 9: "A little understood factor in A/B testing," The BAS Speaker, March 1979, followed by "On the Audibility of Midrange Phase Distortion in Audio Systems" (with John Vanderkooy and Mark Pocock), JAES, Vol.30 No.9, September 1982
The second reference in Footnote 9 is the Lipshitz article I quoted above. What's missing here is the BAS Speaker and Audio Amateur articles.
Even though I don't have all the pieces of the puzzle, I do have enough information to conclude that the statement in the Stereophile article referenced above is a misrepresentation. That was what TSP's point was in a post that has unfortunately been deleted.
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Follow Ups
- RE: Question RE: Atkinson - DBT/Absolute Signal Polarity - andy_c 12/17/0709:03:46 12/17/07 (130)
- RE: Question RE: Atkinson - DBT/Absolute Signal Polarity - rdf 09:30:04 12/17/07 (4)
- RE: Question RE: Atkinson - DBT/Absolute Signal Polarity - andy_c 09:40:15 12/17/07 (3)
- RE: Question RE: Atkinson - DBT/Absolute Signal Polarity - tlyyra 09:43:26 12/17/07 (2)
- RE: Question RE: Atkinson - DBT/Absolute Signal Polarity - andy_c 09:55:48 12/17/07 (1)
- RE: Question RE: Atkinson - DBT/Absolute Signal Polarity - tlyyra 10:04:11 12/17/07 (0)
- BTW... - bjh 09:26:39 12/17/07 (3)
- Atkinson has been offered many chances to set the record straight. - tlyyra 09:52:31 12/17/07 (2)
- What does he have to set straight? If he examines what he wrote - bjh 10:48:13 12/17/07 (1)
- Blessed be the faithful. - tlyyra 11:04:22 12/17/07 (0)
- I seems clear to me that Atkinson *was not in error* based upon the relevant quote. - bjh 09:21:58 12/17/07 (119)
- RE: "I believe..." - tlyyra 09:27:14 12/17/07 (118)
- To be entirely clear the Retraction I mention should come from you. - bjh 10:03:31 12/17/07 (117)
- RE: To be entirely clear the Retraction I mention should come from you. - John Atkinson 13:56:49 12/17/07 (110)
- Would you now also care to point out... - tlyyra 14:07:53 12/17/07 (108)
- More Remedial Statistics - John Atkinson 14:35:18 12/17/07 (107)
- Thank you. - tlyyra 15:12:38 12/17/07 (10)
- RE: Thank you. - John Atkinson 16:26:12 12/17/07 (1)
- RE: Thank you. - tlyyra 17:07:52 12/17/07 (0)
- Yes or No session... - bjh 15:25:55 12/17/07 (7)
- Nice, thanks for helping out. - tlyyra 15:52:46 12/17/07 (6)
- RE: Nice, thanks for helping out. - bjh 16:35:11 12/17/07 (5)
- The lesson learned is simply that... - tlyyra 17:22:15 12/17/07 (4)
- A story about a manufacturing engineer I used to work with... - andy_c 09:16:22 12/18/07 (1)
- Good one... :-) - tlyyra 10:55:43 12/18/07 (0)
- Well at least I would have to say that ... - bjh 17:39:28 12/17/07 (1)
- Now I'll put it really simply. - tlyyra 03:40:40 12/18/07 (0)
- RE: More Remedial Statistics - andy_c 14:45:43 12/17/07 (95)
- RE: More Remedial Statistics - rdf 15:22:44 12/17/07 (94)
- RE: More Remedial Statistics - andy_c 15:59:28 12/17/07 (11)
- RE: More Remedial Statistics - rdf 18:10:37 12/17/07 (4)
- Does it say ANYWHERE in the BASS article... - tlyyra 02:24:19 12/18/07 (2)
- RE: Does it say ANYWHERE in the BASS article... - rdf 08:02:35 12/18/07 (1)
- RE: Does it say ANYWHERE in the BASS article... - tlyyra 11:24:32 12/18/07 (0)
- RE: More Remedial Statistics - andy_c 18:36:48 12/17/07 (0)
- If I may add one more explanatory note re: that "circumstantial" connection. - tlyyra 16:18:14 12/17/07 (5)
- Understood. - andy_c 16:29:04 12/17/07 (4)
- That would indeed be great. - tlyyra 17:26:08 12/17/07 (3)
- RE: That would indeed be great. - andy_c 17:58:40 12/17/07 (2)
- OK, though I'm not sure what's still uncertain. - tlyyra 02:29:02 12/18/07 (1)
- RE: OK, though I'm not sure what's still uncertain. - andy_c 07:50:33 12/18/07 (0)
- More stuff if interested. - tlyyra 15:35:15 12/17/07 (81)
- "...in plain olde English. " - robert young 17:24:16 12/17/07 (80)
- RE: "...in plain olde English. " - John Atkinson 03:56:17 12/18/07 (42)
- Then it seems neither do you. - tlyyra 04:05:59 12/18/07 (41)
- RE: Then it seems neither do you. - John Atkinson 08:32:16 12/18/07 (40)
- RE: Then it seems neither do you. - tlyyra 12:46:39 12/18/07 (39)
- "efforts to undermine the questioner's character" - robert young 13:00:34 12/18/07 (38)
- Except that I have not said any of that. - tlyyra 13:09:49 12/18/07 (37)
- Au contraire! - bjh 16:49:49 12/18/07 (36)
- One more time, but then I won't play your game any more. - tlyyra 02:58:17 12/19/07 (35)
- No, that's right. - robert young 05:00:39 12/19/07 (34)
- That's your conclusion and I am not objecting. - tlyyra 06:00:30 12/19/07 (33)
- " point of grammar????" - robert young 07:58:25 12/19/07 (32)
- Point of semantics. - tlyyra 02:59:25 12/20/07 (10)
- "Is that all you've got left????". - robert young 05:35:39 12/20/07 (9)
- RE: "abuse of language" - tlyyra 06:22:21 12/20/07 (8)
- Please help with a clarification. - robert young 07:00:39 12/20/07 (7)
- Can you describe what the point would be? - tlyyra 08:19:35 12/20/07 (6)
- No, it is at the heart of the point. - robert young 09:35:36 12/20/07 (5)
- RE: No, it is at the heart of the point. - John Atkinson 10:54:33 12/20/07 (4)
- I believe you were expected to give up a limb, - bjh 13:11:29 12/20/07 (1)
- I'm afraid JA stopped patting on your back some time ago already. - tlyyra 13:50:11 12/20/07 (0)
- RE: "I have acknowledged that I may have made an error." - tlyyra 11:30:31 12/20/07 (0)
- Yes, it's time to move on. Nothing to be gained here. - robert young 11:15:29 12/20/07 (0)
- RE: " point of grammar????" - John Atkinson 08:38:22 12/19/07 (20)
- "[Your] Assumed Guilt"? Are you trying to become an Audio Asylum martyr? - tlyyra 02:58:14 12/20/07 (17)
- Why is this so hard for you?? - robert young 05:30:34 12/20/07 (14)
- Just one substantive question left. - tlyyra 06:28:24 12/20/07 (13)
- Administrivia: Stop spreading falsehoods or ... - Ted Smith 11:45:16 12/20/07 (0)
- RE: Just one substantive question left. - pande 08:40:47 12/20/07 (5)
- You are overly dramatic. - tlyyra 08:46:37 12/20/07 (4)
- RE: You are overly dramatic. - pande 09:33:57 12/20/07 (3)
- So was I... - tlyyra 05:12:23 12/21/07 (2)
- RE: So was I... - pande 11:13:02 12/21/07 (1)
- Good for you. - tlyyra 10:05:24 12/22/07 (0)
- If you believe what you wrote, then you are ... - robert young 06:48:27 12/20/07 (5)
- Re: "Intelligent debate..." - tlyyra 06:55:36 12/20/07 (4)
- "leave us intelligently debating!" - robert young 06:59:04 12/20/07 (3)
- That was a parody, Robert dear. - tlyyra 08:28:27 12/20/07 (1)
- All your exclamation points gave away the parody. - robert young 09:29:28 12/20/07 (0)
- My only regret is that I wasted my - bjh 07:57:48 12/20/07 (0)
- Sigh... - John Atkinson 04:19:30 12/20/07 (1)
- RE: Sigh... - tlyyra 05:22:33 12/20/07 (0)
- RE: " point of grammar????" - andy_c 19:28:38 12/19/07 (1)
- Thanks - John Atkinson 04:22:49 12/20/07 (0)
- I rather prefer... - tlyyra 03:12:34 12/18/07 (36)
- RE: I rather prefer... - morricab 04:27:23 12/18/07 (35)
- According to which thesis? - tlyyra 04:41:14 12/18/07 (34)
- It's from your own link!!! - robert young 04:52:27 12/18/07 (33)
- "You can't have your cake and eat it too. " No? - bjh 07:04:37 12/18/07 (0)
- What are you talking about? - tlyyra 06:22:38 12/18/07 (31)
- RE: What are you talking about? - morricab 08:33:44 12/18/07 (30)
- Fine. - tlyyra 13:02:15 12/18/07 (29)
- RE: Fine. - morricab 02:29:24 12/19/07 (28)
- RE: Fine. - tlyyra 03:22:03 12/19/07 (27)
- RE: Fine. - morricab 09:03:55 12/19/07 (26)
- Debunking / Policing on AA / Correcting Errors - tlyyra 04:12:31 12/20/07 (9)
- Administrivia: Stop spreading falsehoods or ... - Ted Smith 11:41:29 12/20/07 (3)
- RE: Administrivia: Stop spreading falsehoods or ... - tlyyra 12:09:25 12/20/07 (2)
- RE: Administrivia: Stop spreading falsehoods or ... - Ted Smith 12:16:06 12/20/07 (1)
- RE: Administrivia: Stop spreading falsehoods or ... - tlyyra 14:03:19 12/20/07 (0)
- Correcting Errors - John Atkinson 04:29:46 12/20/07 (4)
- Correcting More Errors - tlyyra 05:39:35 12/20/07 (3)
- RE: Correcting More Errors - John Atkinson 06:41:51 12/20/07 (2)
- Why not just answer the questions? They would settle it all so very quickly. - tlyyra 08:17:37 12/20/07 (1)
- I'm only replying so you can't delete it. - robert young 10:14:03 12/20/07 (0)
- RE: Fine. - andy_c 20:47:09 12/19/07 (12)
- RE: Fine. - morricab 02:19:23 12/20/07 (11)
- Yes, you are missing something. - tlyyra 03:25:06 12/20/07 (10)
- RE: Yes, you are missing something. - morricab 03:15:50 12/21/07 (9)
- 'Interpretation' and 'reinterpretation' - tlyyra 04:06:27 12/21/07 (8)
- RE: 'Interpretation' and 'reinterpretation' - John Atkinson 11:50:25 12/21/07 (6)
- RE: 'Interpretation' and 'reinterpretation' - tlyyra 11:30:02 12/22/07 (5)
- RE: 'Interpretation' and 'reinterpretation' - John Atkinson 14:57:16 12/22/07 (4)
- RE: 'Interpretation' and 'reinterpretation' - tlyyra 05:37:18 12/23/07 (3)
- RE: 'Interpretation' and 'reinterpretation' - John Atkinson 08:01:18 12/24/07 (2)
- "Semantic forests" and still no evidence you can cite? - tlyyra 08:59:06 12/26/07 (1)
- More mindreading, it appears - John Atkinson 13:51:11 12/27/07 (0)
- RE: 'Interpretation' and 'reinterpretation' - morricab 06:23:28 12/21/07 (0)
- Objection, Your Honor - bjh 09:37:39 12/19/07 (2)
- Right, you have no arguments... - tlyyra 03:27:33 12/20/07 (0)
- RE: Objection, Your Honor - morricab 02:16:49 12/20/07 (0)
- You can thank member andy_c for the research, - bjh 14:03:47 12/17/07 (0)
- Basic math, and another friendly suggestion for you. - tlyyra 10:11:41 12/17/07 (5)
- You again need reminding that your charge of "totally false" pertaining to - bjh 10:28:26 12/17/07 (4)
- 99% instead of 53% is not totally false? - tlyyra 10:46:38 12/17/07 (3)
- Remedial Statistics? - John Atkinson 13:49:47 12/17/07 (1)
- Is it just me or ... - bjh 15:05:02 12/17/07 (0)
- As to the matter at hand I have said all I have to say. However on another point ... - bjh 11:01:41 12/17/07 (0)
- Exactly. - tlyyra 09:19:23 12/17/07 (0)