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Possible differences

I don't think anybody KNOWS the answer to that, I can make some completely unsubstantiated conjectures though.

I have heard this "uncompressed sounds better than lossless compressed" before. The uncompressed was also converted back to original format and was exactly - byte for byte - the same as the original. I've been trying to figure out what might be the cause of this.

The most likely explanation to me is differences in seek timing between compressed and uncompressed files. If you have an uncompressed file that is layed out contiguously on the disk the time between seeks to the next track should be very regular. With a compressed format there is no fixed relationship between time and location in the file, some parts of music will compress better than others. Thus exactly when the drive has to seek to the next track is going to vary. I'm hesitant to use the word, but there will be jitter in the seek timing.

Since the seek is a mechanical movement caused by fairly strong electrical currents through coils, there will almost certainly be noise induced in the power supply wires and EM fields radiated by the drive. The conjecture here is that this noise can affect DAC conversions and bus transmissions that will be subtly audible. And that noise with a higher "jitter" will be more objectionable than that with less jitter. (note this is different than the more commonly discussed clock edge jitter, but the path of audibility might actually go through clock edge jitter)

Since a SSD does not have the high currents going through coils the assumption is that the PS noise and EM fields it emmits will be less than those of a mechanical disk.

Again I have not done any experiments, I have no data to back up any of this, but it seems to me to be the best explanation of observations.

John S.


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Follow Ups
  • Possible differences - John Swenson 14:04:12 05/21/08 (1)
    • Thanks - Dynaudio_Rules 17:48:33 05/21/08 (0)

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