CD Pre-emphasis and ripping

I was looking into why a few of my older CD rips sound bright and thin, say compared to a Tidal stream etc…
And then I discovered, pre emphasis. This is a method kind of like the vinyl RIAA curve but for CD but a mastering option… it was more popular in the late 80s and early 90s… and still occasionally used… apparently with some Indie labels…
However I have discovered my rips of such discs (thankfully only a few) are not playing back correctly, ie they sound incorrectly thin and bright… as either my ripper has not detected the TOC flag or subcode flag and then even if it did, and passed the flag along in the SPDIF Protocol, I don’t believe any of my DACs would recognise this and apply the de-emphasise filter… as really it’s a CD specific thing, even though SPDIF supports it.

My solution would appear to be I need to manually modify the rip by applying the appropriate filter response to the file so the music eq plays back as intended.

So question, what does the Unifi Core do? Does it modify the rip to correctly apply the de emphasis, or does it ignore it providing a rip that will incorrectly play back? Or what do others do?

Try ripping with iTunes, as I understand it, it modifies the rips to remove pre-emphasis. May not give the results you’re after, but worth a try on one CD.

An alternative is

  1. Rip CD with XLD to single WAV & CUE file
  2. Process WAV file with SoX to apply de-emphasis (sox “name.wav” “name_deemph.wav” deemph)
  3. Edit CUE file to point to name_deemph.wav file
  4. Load revised CUE file in XLD
  5. Convert to FLAC as separated tracks.

Sorry no idea what a Uniti Core might do. Hopefully something like the above.

Hi, thanks… yes the main issue is the correction. Cue file etc will be created by the ripper, but unless you process the file some how it will still be wrong.
So are you suggesting sox is a filter programme that applies the correct filter curve?
If so then that is what. I mean, I would need to manually apply the filter
I had understood iTunes no longer applies de emphasis filter to a rip but I could give it a try…

I have never seen anything about the way the Core handles pre-emphasis and I do read most everything I come across about the Core. Maybe @Stevesky will tell us the answer if he happens to see this thread.


Some rippers will identify it and report it but not remove it. I think you use Sox to remove it.

Apparently it’s method can rob the soundstage according to headfi. But I guess it’s worth a punt.

Yes SoX, Audacity or any quality digital filter application.

I wonder if you could create one to be used in Roons DSP?

You certainly can, but there is no way to switch it in automatically as far as I can see

It’s been asked for a few times by the community to apply DSP based on tags and on specific sources but it’s not been implemented. So yeah it would need to be manual and turn it off when done so requires a set routine.

Hi @davidhendon

The Core nor Unitiserve will do the de-emphasis filter for these very early cd’s that were mastered in this way.

It’s a bit of a pain to detect as the TOC is unreliable to use, so the ripping engine has to track the Q subcode information that is embedded in the CD sub-channel data.

This all stems from the days when the ADC’s and DAC’s were 14bit and the pre-emphasis helped on the signal to noise, but was killed off as soon as 16bit DAC’s came out.

Due to there are so few original CD’s that exist that need this, we decided not to do a custom implementation to handle it. The effort vs return isn’t worth it. Typically better off just get a newer mastered version of the CD.


Steve Harris
Software Director

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Simon, could you please list a couple of those albums?

I believe my copy of Dare has pre emphasis, and I have a copy of the James Taylor Quartet, Mission Impossible that sounds like it it has pre emphasis… I suspect I have others

Thanks Steve… yes I guess it’s just easier to manually apply a filter to the rip if required

Which James Taylor Quartet album? I have a few of theirs. Thankfully Dare I only have on Vinyl :slight_smile:

Mission Impossible

Doh! Read you post wrong how did I miss that.

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SoX is a cross-platform (Windows, Linux , MacOS X, etc.) command line utility that can convert various formats of computer audio files in to other formats. It can also apply various effects to these sound files, and, as an added bonus, SoX can play and record audio files on most platforms.

Thanks, it would be interesting to understand how the filter it uses to achieve de emphasis is designed and implemented … that will make a big determination on ultimate sound quality, and it’s performance on micro detail, transients etc

Sound Exchange aka SOX applies the IEC 60908 de-emphasis treble attenuation shelving filter.