結果 The Results

The complete Excel spreadsheet with all test results and participant comments can be accessed herein.After the test, Manny spent quite some time analyzing the results and responses to a post-session questionnaire he composed. I owe much of the following analysis to him.

The total number of correct answers was 73 out of 149, which amounts to 49% accuracy. That is no more accurate than flipping a coin, and therefore, no statistically significant detection of power cable differences.

Test participants were asked to rate themselves as to how much of an audiophile they considered themselves to be. The scale was 1 to 5 where 1 = “I’m not an audiophile at all” and 5 = “I’m a hardcore tweak.” (“Tweak” is the word Manny chose; I would not have used such terminology, which I find belittling in this context). The self-proclaimed hardcore audiophiles got 48% correct; the rest got 50% correct. Again, no significant differences based on whether or not a listener felt he was an audiophile or not.

Those above the median age of 50 scored 43% as a group; those 50 and younger scored 53% as a group. Those who frequently attend concerts of un-amplified music scored 44%, those who don’t scored 50%. Those who play a musical instrument scored 47%, those who don’t 50%. The 9 out of 15 participants who have invested in after-market power cords scored 48%.

Twelve of the 15 participants gave themselves a 3 or better on the 1 to 5 scale of degree of audiophile dedication. Half of the listeners gave themselves a 3 or better regarding their belief that they could hear difference between power cords. Those who rated themselves above the median for their perceived ability to discern differences between power cords scored 49%, the same as those who rated themselves below the median.

Those who on the post-test survey felt most strongly that they had heard differences between cords during the test did not perform better than those who rated their abilities at or below the median. Those who thought they did best scored 45%, while those who thought they did so-so or poorly scored 50%.

The participant who scored best in the first group of 9 was a BAAS member who complained afterwards that it took him half the test to just become comfortable with the music and the sound. He rarely listens to classical music, and found the four selections off-putting. He also expressed a desire for more funk and rock-and-roll. Yet he scored the best of the lot in his test group, with 6 out of 10 correct responses.

二番目のグループ6人の中で二番目の参加者はBASSメンバーで「HONE Your Listening Skills」に出席していました。彼は10個中7個が正解でした。Mannyによると10個中7個は充分満足な数値ではないということです。
The participant who scored best in the second group of 6 is a BAAS member who participated in Hone Your Listening Skills. He got 7 out of 10 right. According to Manny, even 7 out of 10 is not high enough to be statistically significant.

On the post-test survey, 14 out of 15 test participants (93%) answered “Yes” to the question, “Do you feel that the test procedure was reasonable in its attempt to answer the question of the audibility of power cords?”

12 out of the 15 participants (80%) felt that the length of the musical selections was “Just right.” Two felt they were a little long, and 1 felt that they were a little short.

Participants were 80% correct in their responses to the selection from the Berlioz Requiem. Manny calls this “very close to the threshold between chance and perception. None of the other selections produced responses higher than 60%. This phenomenon correlates with John Atkinson’s experience that his participants fared best on massed choral music. If any of us were mad enough to conduct another blind test of this nature, I would choose audiophile recordings of massed choral music for at least 50% of the musical selections. It would be interesting to discover if it would make a difference.

In post-test discussion, several of us noted that we had great difficulty remembering what A had sounded like by the time we got through with X. Several participants said that the way they dealt with this phenomenon was by ignoring A entirely and simply comparing B to X without giving thought to A.

I wish I had tried that. I wish the felt hadn’t been there. But I don’t know if it would have made a bit of difference.

After each session, Manny privately told individual participants who wished to know how well they had performed on the condition that they wouldn’t share the information with anyone in the other group. Needless to say, many of us were dumbfounded. I got only four out of 10 right. Our dog has been licking pie off my face ever since.

Pre-Test Survey:

  1. あなたは自分を「オーディオマニア」だと思っていますか?
    Do you consider yourself an “audiophile?”
  2. これまでにオーディオ用の「プレミアム」もしくは「スペシャル」な電源コードを購入したことがありますか?
    Have you ever purchased “premium” or “specialty” power cords for you audio equipment?
  3. あなたはオーディオ用の「普通の電源コード」と「プレミアムな電源コード」の違いを聞き分ける自信がどれぐらいありますか?
    How strongly do you believe that you you can hear differences between “standard” and “premium power cords in audio equipment?
  4. あなたは現在、楽器を演奏できますか?
    Do you currently play a musical instrument?
  5. あなたはどれくらいの頻度でアンプを通していない生演奏を聞きますか?
    How often do you hear unamplified musical performances?
グループ シート 年齢 性別 質問1 質問2 質問3 質問4 質問5 正解率
1 2 59 男性 5 YES 4 YES 5 40%
2 8 41 女性 2 NO 1 NO 3.5 40%
1 5 43 男性 3 NO 3 NO 2 50%
1 3 62 男性 4 NO 2 YES 5 40%
2 2 34 男性 4 YES 4 NO 2 60%
1 8 45 男性 4 YES 4 NO 3 50%
1 4 47 男性 4 YES 4 NO 3 33%
2 6 50 男性 4 YES 4 NO 3 70%
1 6 51 男性 3.9 YES 4 NO 4 40%
1 7 53 男性 3 YES 3 YES 3 20%
2 5 29 男性 3.5 NO 1 YES 2 60%
2 9 50 男性 3.5 NO 1 NO 2 50%
2 1 57 男性 2 NO 2.5 YES 5 60%
1 1 44 男性 2.5 YES 2.5 YES 60%
2 3 52 男性 3 YES 2 NO 2 60%
50 3.5 3 49%


Test Results:

Post-Test Survey:

  1. あなたは「電源コードを聞き分けられるか」に対する答えを出す試みが、今回のテスト手順で妥当だったとおもいますか?
    Do you feel that the test procedure was reasonable in its attempt to answer the question of the audibility of power cords?
  2. あなたが聴いた違いはどれぐらいの大きさですか?(1=私は違いを全く聞き取れなかった;5=非常に大きい)
    How large were the differences that you heard? (1 = I heard no differences; 5 = Huge)
  3. あなたは音楽の長さは適切だったと思いますか?(1=短すぎる;5=長すぎる)
    Do you feel that the length of the musical selections was … (1 = much too short; 5 = much too long)?
グループ シート 年齢 性別 スコア 質問1 質問2 質問3 コメント
1 2 59 男性 40% はい 4 3 私は聞き慣れたサウンドの聞き慣れた9枚のディスクだったので、幕があることにより、正確にシステムの違いを聞き分けるのが難しくなりました。
The scrim made it much harder for me to hear differences on my system precisely because I am so accustomed to its sound and the sound of nine of the discs.
2 8 41 女性 40% はい 3.7 3 1)アマチュアとして、私は明瞭にAvBを言うことができました。区別の特性を覚えているのはすごく厳しかったです。
1) Though as an amateur I could distinctly tell A V.B. Remembering the distinguishing characteristics was darn tough.
2)本当に、音楽の種類によりました。例えば#7では何も聞き分けられませんでした。#10は明確に違いがありました。テノールの声を聴けたら面白かったでしょう。多様性を持たせるため、ホームシアター用の音楽を聴くのも興味深いと思います。例えばJohn Williamsの7(Seven Years In Tibetのこと?)などの映画音楽。
2) Truly depended on the piece of music. E.g., #7. couldn’t hear anything. #10 distinct difference. Would have been interesting to hear a tenor. Like the diversity, would have been curious to hear maybe music oriented for he “home theatre” end of the spectrum e.g.. john Williams 7 other film scores
1 5 43 男性 50% はい 3 4 音圧を合わせるべきでした。基本的にはテストは成功だったと思いますが、しかしボリュームの違いによりケーブルの正体が分かりました。
SPL should have been matched. In the most basic sense the test was successful, but the difference in volume made the cable identifiable.
1 3 62 男性 40% はい 3 3 X,A,Bは面白いかも知れません。
X,A,B might be interesting
2 2 34 男性 60% はい 3 3 エレクトロニック・ミュージックを使わないでください。ナチュラルでないと違いが分かりません。ベストは小編成のアンサンブル、ブルース・ジャズ・ファンクなど。
Don’t use electronic music; nothing natural to cue on … Best was small ensemble, blues/jazz/funk/ etc.
1 8 45 男性 50% いいえ 3 3 Aの音を記憶しておくのは良くありません。私は結局、BとXを対比しました。
sonic memory of A not to good. I ended up doing B vs. X
1 4 47 男性 33% はい 3 3 幕があると通常の音ではなく実際は別の音でしたが、そう言うものとして、私は別のメソッドを見つけるでしょう。
The scrim was an element in the actual sound that wouldn’t be there normally, as such, I’d find another method.
2 6 50 男性 70% はい 2.5 4 ケーブルを変えるのに時間が掛かりすぎていました。
It was too time consuming changing the cables
1 6 51 男性 40% はい 2.5 2 私自身の選択を幾つか入れて欲しかったです。違いを特定するのは非常に難しかったですが、私が選んでいれば、好みを特定できたと思います。
Would have liked some of my own selections included. I found it extremely difficult, not only to identify differences but, when I could, to identify preferences
1 7 53 男性 20% はい 2.5 3
2 5 29 男性 60% はい 2 3 非常に難しい。選択の間に時間差があったが、状況を考えると分からなくもありません。
Very difficult! Time gap between selections was long, but understandable given the circumstances!
22 9 50 男性 50% はい 2 3 楽しめた。ただちょっと… 右手にあった鏡が、わずかにバランスを崩していました。
Enjoyed it. Small point… the mirror to my right was slightly messing with the balance
2 1 57 男性 60% はい 2 3 ケーブルを変える時間が長くて、例を保有するのを難しくしていました。検眼を行うように「同じ」「違う」というやり方も考えられます。
The length of time to change the cables made it difficult to retain the example. You might think of doing it like the optometrist does. same or different.
1 1 44 男性 60% はい 2 3 最初は「ある」、途中は「いくらかある」、最後は「全く確信が持てない」。難しい課題でした!
1/3 of the time: certain; 1/3 of the time: somewhat certain; 1/3 of time: totally uncertain; difficult exercise!
2 3 52 男性 60% はい 2 3 良いアイディアでした。実際には違いを判別するのはとても難しかったです。
Great idea. Very difficult to determine any differences in reality.
50 2.5 3.0