Excerpt from November, 2004 Stereophile review of Indigo I/O soundcard
"I used iTunes as my primary playback engine, with Apple Lossless Compression applied to the test tracks to keep file sizes manageable. As I wrote in September, ALC compresses AIF files to about 40% of their original size without losing any information. Some readers have asked if ALC changes the sound. But think about it: If the reconstructed file data with ALC are the same as the original AIF, the data presented to the DAC for decoding are the same and the sound must be the same, other than the effects of word-clock jitter. However, though jitter will depend on the stability of the computer's master clock, it will affect ALC and AIF files equally. If the data are the same and the jitter is the same, then the sound should be the same. I certainly heard no differences between an ALC file and the AIF file from which it was made."
Presumably the actual commentary on measurement was in the September, 2004 issue. Unfortunately it does not seem to be online.
"I used iTunes as my primary playback engine, with Apple Lossless Compression applied to the test tracks to keep file sizes manageable. As I wrote in September, ALC compresses AIF files to about 40% of their original size without losing any information. Some readers have asked if ALC changes the sound. But think about it: If the reconstructed file data with ALC are the same as the original AIF, the data presented to the DAC for decoding are the same and the sound must be the same, other than the effects of word-clock jitter. However, though jitter will depend on the stability of the computer's master clock, it will affect ALC and AIF files equally. If the data are the same and the jitter is the same, then the sound should be the same. I certainly heard no differences between an ALC file and the AIF file from which it was made."
Presumably the actual commentary on measurement was in the September, 2004 issue. Unfortunately it does not seem to be online.