You take me to task about introducing variables, but, in the end, variables are what it's all about in most things. Variables can be good and they can be bad. Each of us makes a choice about the variables we can live with.
Sounds like some cloudiness. What would some of these "variables" be? Once you throw unknown external variants into the mix, comparing audible qualities between lossy and lossless compression formats becomes invalid. Comparison between
any two formats is in fact invalid at that point.
Yes, you are correct that it is unlikely that I will change my mind, but not because I refuse to accept the facts as you and Matt may present them, but because I see and hear the "facts" differently. This doesn't necessarily mean that one of us must be wrong. Two + Two = 4, but so does 1+1+1+1.
"see" the facts differently? Since you brought it up. . .how about something like this:
- Start with 2 channel, 16 bit, 44KHz PCM audio sample (.WAV)
- Use the best MP3 encoder you can find at its highest setting (.MP3)
- Use the best APE encoder you can find (.APE)
- Use an audio spectrum analyzer to compare all three
- Use MC to play all three via digital out from the same sound card in the same PC. Capture the output and compare the results from all three.
The capture of the PCM stream from the audio cards will be difficult for most home users, but the first comparison will work just as well.
You should find that the APE and WAV graphs are identical and the MP3 graph will differ. This has been done and this is the case. If you "hear" a difference between APE and WAV then there is another factor involved that is unrelated to the lossless format.
PC DRAM adds another layer of variability, as does the hard disc with write errors
Hard disk with write errors? Any non-detected write errors on a hard disc, cdrom (
not cd-audio format, which would be a typical music CD), or other permanent storage device is considered a
failure and results in corruption. If your hard disc did not reliably store data your OS (windows, linux, macos, etc) would fail. Drive circuitry is responsbile for ensuring that what gets written to it is exactly what gets read. . .with an indication when this is not possible.
I also don't necessarily accept that an APE compressed file = CDA uncompressed file, and hence sounds 100% transparent. If there is a perfect compressor out there, I have yet to hear any authoritative group proclaim its existence.
Now I'm totally lost. What do you consider a "perfect compressor"? A "lossless" compressor (of which APE is one) takes a source and simply stores it in another format using less space with no loss of information. Period. In other words, start with file 'A'. Compress with APE to create file 'B'. Decompress 'B' to create file 'C'. Compare 'A' and 'C'. By definition 'A' and 'C' will be bit-for-bit identical. As Matt has already said - if they are not then there is something else wrong.
If you try this using MP3 instead of APE, you will find that 'A' and 'C' are absolutely different. MP3 is a 'lossy' format and by definition it throws away information to reduce size.
Given that the D/A converters and analog circuitry are common when playing WAV, APE, MP3, then any audible differences between APE and WAV are purely psychological. The source into the D/A is identical, and everything beyond that point is common. An MP3 will result in a difference since the source will be different. The extent of the
audible difference is purely subjective when dealing with lossy formats and there have been many works written about this subject.
So, if being able to recreate the original source bit-for-bit identically does not meet your definition of 'perfect compressor' what is your definition?
When playing APE files from the computer though my stereo system vs. playing the pressed CD on my standalone equipment, the differences are more noticable every time. Since we can't burn and play native APE files on standalone players, there is no way to tell if APE would sound the same as a pressed CD on a stereo system outside of the computer environment.
Ah - but this difference is not due to APE vs WAV - it is due to completely different sets of DACs, cables, and possibly other analog equipment. It is known that even two same-part DACs from the same manufacturer can produce slightly different analog waveforms from the same digital source (though not likely audible) so unless everything including and between Digital/Analog conversion and the listener's ears is common you absolutely can not make any claims about the digital source sounding different. This is a fundamental of conducting testing/experiments. Your testing has far too many variables to make any claims about any single component.
While you may not be able to play APE on your standalone player you certainly can play WAV on your PC. RIP a CD to your PC. Encode to APE. Use MC to play both the ripped WAV and the encoded APE.
Better yet - perform a proper double-blind experiment and see if you can still hear a difference.