DAC IV stages Reply #75 – 2013-03-04 16:28:58 Quote from: Arnold B. Krueger on 2013-02-27 15:30:59Quote from: John_Siau on 2013-02-27 14:10:26In the tests we ran (Macbook vs. DAC1), the gain control was 16-bit undithered due to the fact that iTunes 7.X was not available at the time. The iTunes volume control was used in the test. The existence of 16-bit truncation was verified with an AP System 2, and can be heard in the fade-out at the end of the samples I posted on this forum.Can this be summarized as saying that those tests wouldn't produce the same results if repeated today using up-to-date iTunes software?The results may be different. The truncation artifact would be eliminated if it was caused by iTunes. The operating system may also need to be updated to eliminate the truncation. These changes should eliminate the truncation artifact (one of two artifacts that made ABX detection easy). The second artifact (noise) probably would not change.One could argue about which artifact is more objectionable, but I have no intention of doing that here. ABX tests are intended to detect audible differences and do not tell us anything about which "sounds better" when a difference is detected.