I had to learn about ripping CDs that have pre-emphasis a few months ago when I bought an original issue C2K version of "The Wall". I ripped it and played it and it didn’t sound right. Played it on a home stereo system and it was good. Played it on the computer from the DVD drive and it sounded wrong. Played the rip and it sounded wrong. What was going on? So began my journey.
CD emphasis was implemented in order to get better linearity in the high-frequency range given the capabilities of old school A/D and D/A converters. The CD gets mastered with pre-emphasis and a flag indicating pre-emphasis is present. At playback the DAC applies de-emphasis. Pre-emphasis adds a high-frequency boost. De-emphasis applies a complimentary high-frequency cut to get the signal back to flat.
There is a good explanation of CD emphasis in an article at audioXpress OnLine. The article is in their PDF archive. Direct linking to the PDF file doesn't work so go to the PDF archive and search for "A De-Emphasis Test CD" by Gary Galo.
Ripping a CD bypasses the DAC in the CDR drive and since it is the DAC that is responsible for applying de-emphasis, the de-emphasis doesn't get applied unless the ripper software does it.
A few older rock CDs from the 80s have pre-emphasis. A larger number of classical music CDs from the 80s have pre-emphasis and some classical releases today continue to have pre-emphasis. If you have a collection that includes classical music you likely have a few CDs with pre-emphasis. In my collection of classical music I found that most of the BIS recordings had pre-emphasis, a few of the Delos recordings had pre-emphasis, a Deutsche Grammophon and a Telarc had pre-emphasis.
How to rip a pre-emphasis CD the easy way
iTunes does the right thing and automagically applies de-emphasis if it detects that you are ripping a CD that has the pre-emphasis flag. It is the only ripper that I know of that does that automatically for you.
But there is a downside to that easy way. Apple's de-emphasis process causes a loss of soundstage or stereo separation. I compared a rip of Pink Floyd's "The Wall" done with iTunes (version 8 for Windows) and a rip processed manually using SoX to do de-emphasis, and the version done by SoX sounds better. So the easy way isn't going to do for those who want the best possible sound quality.
How to rip a pre-emphasis CD the hard way
Both EAC and dBpoweramp can tell you if a CD has pre-emphasis. EAC has a column on the far right hand side in the UI. You'll likely have to scroll over to see that column unless you have a large monitor and the EAC window is expanded. Unfortunately that column is hidden for most people and easy to miss.
dBpoweramp also has a column that tells you if a CD has pre-emphasis. Unfortunately that column is not displayed by default. You have to manually add that column to the UI. Right-click on the column display and select the "Track Technical" field. That will add the column that will tell you if a CD has pre-emphasis.
Unfortunately both EAC and dBpoweramp may tell you that there is pre-emphasis, but they don't make that information obvious or alert you that you are about to make a rip that won't sound correct. I saw a forum post by the developer of dBpoweramp that the next version may include a process for de-emphasis. We can hope.
The easiest workflow I came up with is to use EAC to create a CUE file
1) Rip the CD using EAC to a single WAV and CUE file
2) Process the WAV file with SoX to apply de-emphasis
Use the command: sox "foo.wav" "foo_deemph.wav" deemph
3) Edit the CUE file in a text editor to point to the foo_deemph.wav file
4) Load the CUE file in Foobar2000
5) Select the tracks from the CD, right-click, and select Convert. Convert to FLAC or your favorite format.
SoX is a command line program. It is available on SourceForge: SoX - Sound eXchange
To run SoX you will have to know the basics of how to change directories and run programs in a command prompt window. If you are a command line geek you can add the SoX files to your path. If you don't know what a path is you can copy the sox.exe and cygwin1.dll files to the directory where the WAV file is.
The EAC Ripping Guide has a page on pre-emphasis. The guide also uses SoX. But the process described can be simplified. The current version of SoX for Windows no longer has problems with file names that have spaces. So the section in the guide about renaming the files to remove spaces can be avoided.
Ripping to a single WAV and a CUE file also simplifies things. The single WAV file means there is only one WAV file that needs to be processed with SoX. The CUE sheet contains the basic tagging information like album and tracks so when you load the CUE file in Foobar2000 you'll get basic tagging info done when you convert the tracks to FLAC. Only one file to process and automatic tagging of the converted files.
The EAC Ripping Guide links to a command line tutorial to help those who are not familiar with running commands from a command prompt.
And a little something so forum searches can find this thread
pre-emphasis de-emphasis preemphasis deemphasis preemph deemph