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In Reply to: Forget storage comparison. Even the same storage can sound different with different file copying methods posted by Windows X on August 21, 2016 at 14:07:24:
When you hear differences in two digital files, the first thing to check is that the two files have the same contents. Without doing this, any further discussion is pointless. The proper way to do this is to use a software tool to calculate a cryptographic checksum of the file, such as MD5. This will catch every bit in the file that a player application will see. If the checksum doesn't match then there is a further check to see if the differences involve the audio samples as well as the file block structure and metadata. Exact Audio Copy has a utility that does this, and any audio editor can create a difference file of the audio samples by mixing out of phase. There are real examples where two files have different file checksums, but identical audio samples. (This happens sometimes when using dbpoweramp to convert WAV to FLAC and then FLAC back to WAV. The two WAV files will have identical audio samples, but different content, either in metadata or file headers and chunk structure.) Note also that even if the file contents are identical, the operating system metadata may not be. This will certainly be the case if two files reside on the same volume, as they will have different file names and reside in different locations.
The real problem is that DAC manufacturers do not use known methods of isolating the digital input side of their product from the analog output side of their product. A related problem is that reviewers of high end DACs do not review these products with low end transports and computers, which they should do, because a high-end DAC should come with the best possible isolation.
Designers of analog to digital converters and digital to analog converters were aware of the necessity for isolation back in the early DACs. In 1961 I used an analog computer coupled to a digital computer and there were lots of rules as to how these machines were to be connected so as to reduce digital noise in the analog gear.
Bottom line: bits should just be bits. They are not and this can easily be shown by measurements as well as by listening.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
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Follow Ups
- RE: Forget storage comparison. Even the same storage can sound different with different file copying methods - Tony Lauck 08/22/1606:57:43 08/22/16 (1)
- RE: Forget storage comparison. Even the same storage can sound different with different file copying methods - Windows X 07:08:20 08/22/16 (0)
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