How does TuneBrowser handle CD (.wav) files with 'Pre-Emphasis'?

フォーラム TuneBrowser How does TuneBrowser handle CD (.wav) files with 'Pre-Emphasis'?

このトピックには3件の返信が含まれ、2人の参加者がいます。3 週間、 5 日前 Tiki さんが最後の更新を行いました。

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  • #5021

    Andrew ACTON
    参加者

    Greetings Tiki

    I have a question about how TuneBrowser plays back ‘ripped’ Compact Discs (.wav format) with  ‘Pre-emphasis’.

    Questions:

    (1) Does TuneBrowser detect CD (.wav) files that contain pre-emphasis?

    (2) If TuneBrowser can detect pre-emphasis, does it automatically apply (digital) de-emphasis?

    (3) If TuneBrowser can manage (.wav) files with ‘pre-emphasis’ could a new indicator “EMPH” be added (like those for “Tune Samplerate” “Device SampleRate”. It would be very useful to see some dynamic indication in TuneBrowser … regarding pre-emphasis processing.

     

    From my reading, Compact discs ‘ripped’ to a computer (.wav) WILL INCLUDE the 2 pieces of data to tell the playback device (CD player or software program) to apply de-emphasis for a CD that was mastered with Pre-emphasis:

    (1) A setting in the CD TOC.
    (2) CD Subcode data in each track.

    Background:

    In the early years of the Compact Disc, some CDs were encoded with ‘Pre-emphasis’ (particularly those from Japan). When a conventional CD player detected a CD with ‘Pre-emphasis’ the signal was de-emphasised with analogue circuits in the CD player to restore the correct frequency response.

    Some HI-Fi CD players (I personally had one) also indicated “Emphasis” in their graphical display to indicate the playback of a disc with “Pre-emphasis”.

    Perhaps TuneBrowser can be one of the few programs to correctly handle audio (.wav) files, which were encoded with ‘pre-emphasis’  🙂

    With thanks (as always),

    Andrew Acton

     

    Ref: https://en.wikipedia.org/wiki/Compact_Disc_Digital_Audio

    “Pre-emphasis”
    Some CDs are mastered with pre-emphasis, an artificial boost of high audio frequencies. The pre-emphasis improves the apparent signal-to-noise ratio by making better use of the channel’s dynamic range. On playback, the player applies a de-emphasis filter to restore the frequency response curve to an overall flat one. Pre-emphasis time constants are 50µs and 15µs (9.49 dB boost at 20 kHz), and a binary flag in the disc subcode instructs the player to apply de-emphasis filtering if appropriate. Playback of such discs in a computer or ‘ripping’ to wave files typically does not take into account the pre-emphasis, so such files play back with a distorted frequency response.[citation needed]”

    #5023

    Tiki
    キーマスター

    Hi,

    Thank you for your detailed explanation.

    About one year ago, it was talked about pre-emphasis in this forum.

    https://tunebrowser.tikisoft.net/forums/topic/799/ (In Japanese)

    Unfortunately, TuneBrowser is not support pre-emphasis (de-emphasis). I have no resource to do de-emphasis. I’m sorry, but I could not meet your expectation at this time.

    Thanks.

    #5026

    Andrew ACTON
    参加者

    Hi Tiki

    Thank you for your quick reply.

    It is my mistake because I searched the forum in English for “pre-emphasis” and did not find your original answer.  I should have used Japanese language search and locate the old answer regarding “プリエンファシス” !

    Since I can only read my (native) English… normally I use Google translate to read the (mostly) Japanese forum.  🙂

    Many thanks,

    Andrew Acton

    #5027

    Tiki
    キーマスター

    Hi, Andrew

    I know it is not easy to search old topics. Especially by differnet languages. So, off course, it’s not your mistake. Please do not mind.

    And now, I’m going to restart studying Pre-emphasis (and also HDCD). These are old technologies in this Hi-Res days, but I understand that it can not be ignored.(^^)

    Thanks.

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