Re: MP3/Ipod vs. C.D.?
This might go right over some of your heads, other people who have an understanding of electronics or physics will get it.
Anytime you have to convert from analog (sound, vibration) to digital (on/off, 1 or 0), YOU ARE TAKING A LOSS.
Digital to Analog conversion, or D/A is a loss.
This means that anything "Digital" is going to sound worse from the time it was recorded. Unless, somehow, every detail of sound was converted to 1's and 0's and stored perfectly, which is impossible. Sound is analog. Storage on computers, CD's, Mp3's is digital.
This is why some people prefer 1980's or high end Analog sound gear for "audiophile" listening experiences.
The more times you convert from analog to digital, the more loss you have. The recording was most likely done on an analog tape machine at the studio or digital recording studio operating at a lot higher rate than your 44Khz CD (referring to bandwidth)....more likely 192Khz or so bandwidth in the studio. More ability to capture sounds.
Now the CD has been compromised because it only holds so much sound information in its digital state. It's 44Khz instead of 192Khz or infinite (analog).
The sound has been converted at least 2 times from analog to digital at this point.
Ripping music from CD's to MP3, even at 320Khz....at least one more conversion. This time, digital to digital (usually). Another loss, especially when compressing music. Something has to be lost to convert from a 40MB WAV file to a 7MB MP3.
Now you are playing the MP3 through your HU using an Aux cable.... Aux is analog (headphone) to analog (line in). Another loss.
The HU converts the analog signal from the Aux port back to Digital one more time. Another loss.
If you use your USB cable, at least your iPod/Mp3 player is going digital to digital to your HU....eliminating 1 loss.
Without counting the above losses, you are converting the audio from analog to digital at least 3 - 5 times just playing music from your iPod/MP3 player into your head unit. Each time is going to take a noticeable hit.
Play an original recording (master) or Download a FLAC recording from an artist or even a good quality CD. Play that through your home stereo. Now hook up your MP3 player through some RCA cables and play your average 192Kbps MP3 and listen to the cymbals any horns or high pitched instruments. Notice a huge loss of decay and detail? Now try a 320Khz MP3. Hear the difference?
If you don't, its not going to matter for you anyway.
Here is some good reading about the subject:
"CD audio is not good enough"
CD audio is not good enough - Hydrogenaudio Forums
Why Neil Young Hates MP3
'65 VW Bus
MA Hippo 122, (2) Aura Sound 8's, (2) SoundStream 6.5 coax, (2) Alpine Type-S 6x9's [rear fill], MBQ DSC1500.1D, RF 501X
'02 BMW 330xi (AWD coupe), every option
Harman/Kardon 12-speaker System Option + Dayton HO D4 10" and PPI Ion 650.1 in sealed box
And many more car audio goodies in storage