How Can I Tell If a CD Uses Pre-Emphasis, and How Does It Affect the Sound?

[Michou]

I've been trying to figure out whether any of my CDs were mastered with pre-emphasis.

Is there a reliable way to tell if a CD uses pre-emphasis? Can this be determined from the disc itself, by ripping it with specific software, or from the TOC/subcode information?

Also, if a CD with pre-emphasis is played or ripped without the proper de-emphasis being applied, how much does it affect the sound? Is it a subtle change, or is it usually obvious? What are the typical sonic characteristics of a CD that's missing de-emphasis?

I'd appreciate any advice or recommended tools for checking this.

 

[voodooless]

HOW-TO: CD Pre-Emphasis & Using SoX De-Emphasis. (And the decline of physical media with vinyl revenue > CD now.)

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

 

[linuxfan]

Is there a reliable way to tell if a CD uses pre-emphasis? Can this be determined from the disc itself, by ripping it with specific software, or from the TOC/subcode information?

I answered all those questions in a post last year -
https://www.audiosciencereview.com/...ffect-on-sound-of-cd-rips.67526/#post-2453574

Also, if a CD with pre-emphasis is played or ripped without the proper de-emphasis being applied, how much does it affect the sound?

It will sound quite "bright" - which is to be expected, since pre-emphasis raises the higher frequencies.
The difference is not subtle, but at the same time it might not be obvious, since over the years we have come to expect a wide range of mastering tastes, and at first listen it may just seem that it's a poor mix.

 

[linuxfan]

This online list is an easy way to check -
https://studio-nibble.com/cd/index.php?title=Pre-emphasis_(release_list)
although you will see they list quite a few titles as "?" which I take to mean suspected, but not confirmed.

 

[uliwer]

Here is an older thread about pre-emphasis which also points to some problems:

Pre-/ De-emphasis via S/PDIF

I started the topic in the DX 3 pro+ thread. Meanwhile I made some observations. The DX 3 pro+ decoded the emphasis when fed by a Pioneer BDP 450 (coax) but not when connected with a Marantz CD 5001 (coax or optical) or a Sony D-NE 700 (optical). A Pioneer NC 50 DAB decoded the emphasis when...

www.audiosciencereview.com

Unfortunately the Redbook for CD standards allowed two ways to signal pre-emphasis:
1. The most used was in the CD’s table of content (TOC). You can look into the TOC, e.g. by typing „drutil toc“ in Terminal for MacOS (there should be also ways for Windows which I don‘t know as I don‘t use Windows).
2. Even if the TOC says that there was no pre-emphasis it does not necessarily mean that pre-emphasis wasn’t applied for the recording as it could be also signaled in the CD‘s subcode. I don‘t know how to read the subcode.

The problem is that only CD-players which strictly adhere to the Redbook detect both ways of pre-emphasis in the recording and apply de-emphasis in the replay. Modern players - especially if they can play SACD and/or Blue-Ray-Discs - don’t react if the pre-emphasis is signalled only in the subcode or ignore the pre-emphasis signal at all. With these players you run the risk that the replay is too bright. That is also true if you rip the CD and the ripping software ignores the signal - so you get ripped files which are too bright. Same with some DACs if their processors ignore the signal - that‘s the problem the thread linked above dealt with.

The problem goes even further for some downloads offered by labels which made ample use of pre-emphasis for their recordings. One (bad) example is the Swedish classical label „BIS Records“. They used pre-emphasis not only in the early 80s but way into the 90s - not regularly but also not rarely. When they started to offer their recordings for downloads they didn‘t care about whether pre-emphasis was used and so put them up for paid downloads without de-emphasing them and of course not signalling the fact. When the label was criticized for this practize the former owner Robert von Bahr even admitted that some downloads had a problem and promised they would correct this. Though I am not sure whether they corrected everything. So if you have a download from their recordings they made in the 80s to 90s you only can find out by listening whether they are too bright or not, which may be difficult if you don‘t have a reference without pre-emphasis.

 

[linuxfan]

@Michou if you find any pre-emphasized CD's in your collection, check back here about the different de-emphasis software options.