trose49,
There are certain things that can be changed within a sound file, that no human can ever detect. A high end microphone can essentially hear everything, and record it. What does this mean? It means sounds that are very quiet, even near silent, are picked up by the microphone just as equally as the extremely loud sounds. If you place a microphone in a concert, it will record all sounds within it's frequency range, and organize them together accordingly. Imagine this---you are at a rock concert, the sound levels are loud enough to almost hurt---a person 10-15 rows away sneezes. Will you hear it? The microphone will, and it will be recorded as background information in the track. A lossy compression format will remove this sound from the signal, since it will determine it is essentially impossible for you to hear it, so it can save space by removing it. You can say, "BUT I WANT EVERYTHING KEPT!". I agree with this mindset, which is why I use FLAC. But to say, "I can hear that man sneeze with the FLAC, and I can't hear it with the AAC", is just plain wrong, since 99.9999999% of the time, you WILL NOT hear that sound, whether you use lossless or not. Follow?
Now to address a few things regarding your belief of "always being able to pick them out".
This is actually very common. That is, people claiming they can hear a difference on an iPod or other portable-player-based setup, but fail when the source is their PC. Ipods (and other portable players) have different decoding filters for different file types. It is not only possible, but commonplace, to hear a difference between, say, a WAV file and a 256kbps AAC file simply because they are decoded differently on the portable player. One may sound a fraction of a decibel louder (or lower) as a result of this. Equalizers are also applied differently, so if you use any EQ settings for playback, those DSP effects will be different for different formats. This can cause lossless and a lossy format to sound different from the iPods decoding or filtering alone, so I have no doubt that it is possible for you to hear some difference on this platform----I have done it myself.
Having said that, if you are set on not using the PC, the test can still easily be done.
First, you need to rip a handful of tracks (using EAC, Secure Mode) to WAV. Archive the uncompressed WAV's somewhere. After ripping them to WAV, compress the WAVs to 256 or 192kbps AAC files. Then, using Foobar2000, decode the AAC files back to WAVs. You should now have 2 wavs for each track---one which is truly lossless, and another which is lossy. Put them into 2 different folders, "AlbumName-Lossless" and "AlbumName-AAC", then put both of these folders on the iPod.
Once this is done, you need someone else to select the tracks for you. You should have your backs turned to each other, so they cannot in any way influence you. You select which song from the album you wish to attempt to ABX. They will play that song at random from 1 of the folders, not telling you which one. They play one, you guess which it was. They do NOT tell you if you were correct or incorrect, they merely write down whether you were right or not. Do this multiple times. Guessing once does not count---you have a 50-50 chance. So you need to guess correctly several times in a row--at least 12-16 minimum. If you can do this with the test setup exactly as I described, then it could be declared that you do genuinely hear a difference.
I have always been happy to organize such tests for people who claim to have "Golden Ears". Remember---if you can truly hear the difference, no one can fool you, and you will always know which is which, so you should feel perfectly comfortable letting someone else organize and run the test. If you can hear the difference, you are in control no matter what. But it is very important that someone else be in control of administering the test, in order to keep results relevant. If you used an ABX program on your PC, this need is met, since the program is in control of the test and randomly selecting tracks. Using your iPod setup however, you will need another person to assist. A person who understands how the test needs to be done, and gives it to you accordingly.
