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Author Topic: De-emphasis and pre-emphasis.  (Read 3758 times)

AndyU

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De-emphasis and pre-emphasis.
« on: September 18, 2014, 11:59:40 am »

I discovered long after I ripped my cds that some of them might have been issued with the pre-emphasis flag set, and so need de-emphasis on playback for the correct balance. This seems to have been an issue with some early jazz and classical cds, and would explain how a few of my rips sound horridly bright in a way I don't recall the cds sounding. I've had a dig about the forum without any clear result - what I'm really after is a de-emphasis DSP option to apply the correct equalisation. Or a plug-in or some-such. foobar (cough,cough) recognises the PRE_EMPHASIS tag and corrects; iTunes (believe it or not) applies de-emphasis on ripping. But I'm dyed-in-the-wool Media Center user .. anyone got any ideas?
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6233638

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Re: De-emphasis and pre-emphasis.
« Reply #1 on: September 18, 2014, 02:00:20 pm »

You can apply de-demphasis processing to albums using SoX.
http://sourceforge.net/projects/sox/files/sox/14.4.1/sox-14.4.1a-win32.zip/download
 
To make this process easier, edit the "batch-example.bat" or create a new batch file using:

Code: (Batch File) [Select]
cd %~dp0
mkdir converted
FOR %%A IN (%*) DO sox %%A -b24 "converted/%%~nxA" deemph
pause

Then you can just drop tracks onto the batch file one at a time, and they will automatically be converted to a 24-bit file with de-emphasis applied, and placed in the "Converted" folder.
 
 
Unfortunately neither Media Center nor dBpoweramp (the tools I use) report whether a disc is using pre-emphasis or not, but it is generally very rare and only applies to older CDs.
 
Here is a list of discs known to use pre-emphasis, though I don't know how comprehensive it is:
http://www.studio-nibble.com/cd/index.php?title=Pre-emphasis_(release_list)
 
As far as I am aware, only two discs in my library use it - one of which is not on the list.
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gappie

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Re: De-emphasis and pre-emphasis.
« Reply #2 on: September 18, 2014, 02:14:46 pm »


Here is a list of discs known to use pre-emphasis, though I don't know how comprehensive it is:
http://www.studio-nibble.com/cd/index.php?title=Pre-emphasis_(release_list)
 
As far as I am aware, only two discs in my library use it - one of which is not on the list.
hmppfff i have this little alarm bell going.  :o and i did some panic reading, but i do not understand. so there are apparently cd's that have a pre_emphasis flag (  ? ) and it is set in the tags (where, on the cd, or the ripping program, but then, where did they got the info from). i have a bunch from what is on that list.. do i have to search in my attic for them to see if it are indeed the same cd's and do something with them and wash my ears.. i ripped all with mc..  :P

 :)
gab
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6233638

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Re: De-emphasis and pre-emphasis.
« Reply #3 on: September 18, 2014, 02:23:49 pm »

Generally it's only discs produced in the 80s that use it, and they're usually quite grating to listen to without the de-emphasis.
 
It's not something to be too concerned about.
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AndyU

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Re: De-emphasis and pre-emphasis.
« Reply #4 on: September 18, 2014, 02:34:13 pm »

You can apply de-demphasis processing to albums using SoX.
http://sourceforge.net/projects/sox/files/sox/14.4.1/sox-14.4.1a-win32.zip/download
 
To make this process easier, edit the "batch-example.bat" or create a new batch file using:

Code: (Batch File) [Select]
cd %~dp0
mkdir converted
FOR %%A IN (%*) DO sox %%A -b24 "converted/%%~nxA" deemph
pause

Then you can just drop tracks onto the batch file one at a time, and they will automatically be converted to a 24-bit file with de-emphasis applied, and placed in the "Converted" folder.
 
 
Unfortunately neither Media Center nor dBpoweramp (the tools I use) report whether a disc is using pre-emphasis or not, but it is generally very rare and only applies to older CDs.
 
Here is a list of discs known to use pre-emphasis, though I don't know how comprehensive it is:
http://www.studio-nibble.com/cd/index.php?title=Pre-emphasis_(release_list)
 
As far as I am aware, only two discs in my library use it - one of which is not on the list.

Thanks for the sox magic. Will probably have to go that way. But notice that since version 14.2 dBpoweramp DOES show whether a disc is using pre-emphasis or not. It will show it in the "Track Technical" column of the main view, but this is not displayed by default. So, if you set the PRE_EMPHASIS tag appropriately, and use a player like foobar that applies de-emphasis all is well with playback. I agree that this might not affect many cds, but I suspect I have a good handful of classical rips and a few  Jazz that are affected and I'd prefer to play them back right!
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gappie

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Re: De-emphasis and pre-emphasis.
« Reply #5 on: September 18, 2014, 02:35:43 pm »

Generally it's only discs produced in the 80s that use it, and they're usually quite grating to listen to without the de-emphasis.
 
It's not something to be too concerned about.
ok.. cool.. my wife always says, that when she met me 27 years ago i was cool because i had 10 cd's and a broken cd player (and a lot of vinyl  ::) )...

thanks... i can live with that

 :)
gab
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6233638

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Re: De-emphasis and pre-emphasis.
« Reply #6 on: September 18, 2014, 03:38:50 pm »

But notice that since version 14.2 dBpoweramp DOES show whether a disc is using pre-emphasis or not. It will show it in the "Track Technical" column of the main view, but this is not displayed by default. So, if you set the PRE_EMPHASIS tag appropriately, and use a player like foobar that applies de-emphasis all is well with playback.
Good to know - I must have missed that change.
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