Learned something new today and it isn't good.


I have been in this crazy hobby for over five decades and thought I knew most of the basic information regarding audio quality.

That was before this morning.

Today I learned about the practise of applying "pre-emphasis" to CDs that was around during the late '70's and early '80's. Apparently this practise was developed as a way of reducing the signal to noise in digital audio. The problem is this was a two-part process and required the CD player to have a "de-emphasis" capability to allow the disk to play properly. Without the application of de-emphasis, cd's would sound "bright".

My question would be, "Does everyone else know about this?"

If you do, "How do you deal with it?"

I still listen to CDs and this is not something I need in my life.

128x128tony1954

Pre-emphasis is very likely dead IMHO, because ripped CD's data doesn't carry pre-emhpasis bit. A lot of people use servers and music with pre-emphasis would sound bad (+9.5dB@20kHz) without de-emphasis.  Some ripping programs might contain plug-in to de-emphasis if needed. There are programs (like SoX) to de-emphasis digital data, but it is additional hassle (to find out if it is needed and convert every song).

(In common CDP to DAC setup  S/Pdif carries pre-emphasis bit to DAC)

I have not played a CD disk that I would have suspected Not having such de-emphasis.  Like I hear playing a record without RIAA de-emphasis.  Or Dolby encoded tapes.  It's not broken.  You don't have to deal with it.

This has nothing to do with noise or noise reduction. Why does that keep getting repeated??

It was a necessary step to deal with the natural operation of early DACs.

One of my colleagues sent this. It is not light reading but the concept seems easy to understand.

https://www.analog.com/en/technical-articles/equalizing-techniques-flatten-dac-frequency-response.html

I read about this years ago and now am using a Audiolab 6000CDT. Before the 6000, I was using an Oppo and never noticed anything saying something was emphasized or deemphasized, so I just ignored that about one in a hundred disks sounded a bit bright.

@erik_squires 

Thanks. Nice to get a response that is based on actual research and facts, as opposed to a lot of guesses and hypothesizing.

Researching information about any topic.

Wasn't that what Google was for, before they tried to take over the world?