ABX Double Blind Comparator Data
May 7, 1977
The Original SMWTMS ABX Test Results
| Power Amplifier Comparison | Result | Correct | p less than | Listeners |
|---|---|---|---|---|
| 10 Watt Tubes vs. Dyna 400 |  |
63 / 80 = 79% | 0.0005 | 10 |
| Paoli 60M vs. Dyna 400 | |
78 / 126 = 62% | 0.005 | 9 |
| Swartz 40* vs. Dyna 400 |  |
41 / 84 = 49% | - | 6 |
| These were the first three audio double blind tests ever done. |
| * The Swartz 40 is a 20 Watt per channel power amplifier with quasi-complementary ouputs built exactly to the five transistor per channel design in the RCA Transistor Manual. By the espoused standards of subjectivists, nothing should sound worse than this amplifier. |
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The different symbol means it is unlikely the percent correct score occurred by chance and thus the null hypothesis was disproven, which substantiates a real difference in sound quality. |
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The same symbol means that it is likely the correct score occurred by chance, the null hypothesis is not rejected, which means no difference was found. It does remain possible a difference may be substantianted with further testing. |
Send questions or comments on the ABX Web Page to David Carlstrom.