Resample at the end or the beginning?

Discussion in 'Mastering' started by Jemvie, Jan 31, 2005.

  1. Jemvie

    Jemvie Guest

    Greetings ppl.
    I extracted some music tracks from a concert DVD and these are in PCM 24Bit/48Khz .wav files, so I'm going to make them CD-ready (16Bit/44.1Khz) in SoundForge 7.0 but I was wondering if there is any impact on quality if I lower the bit-depth first and then do the SRC or should I do it the other way around?
    I'm thinking If I change the bit-depth when the songs are still in 48KHz the noise can be shaped to frequencies even higher away from 20KHz (24KHz+, instead of 22KHz+) this is the only advantage I can think of doing the bit-depth convertion first, but I'm kind of noob in this so I could be totally wrong, maybe someone can put me out of my doubts?

    btw these are the settings I'm using

    Resampling:
    Interpolation Accuracy = 4
    Apply and anti-alias filter during resample = yes

    Bit-depth converter:
    Dither = HighPass Triangular
    Noise shaping = High-pass contour :D
     
  2. Michael Fossenkemper

    Michael Fossenkemper Distinguished past mastering moderator Well-Known Member

    Well you theory would be somewhat valid if you were able to custom tailor your dither. But they are fixed curves so you are not going to have a difference. Plus dither is very low in level. What i tend to do is process everything at it's native resolution and SRC at the end capturing it at 24/44.1. From there I bit reduce. The reason I do it this way is 1) Sometimes the SRC can cause an overshoot in regards to level, this allows me to correct for it if it does. 2) I believe that SRC increases the wordlength so if you go to 16 bit then SRC, it will go back up to 24 bit and then technically you would have to go back down to 16 bit. Hopefully the SRC will do this automatically. So I would SRC and then bit reduce.
     
  3. Ed Littman

    Ed Littman Guest

    uh oh...some folks here may jump on you for believing that.... :lol:
    Ed
     
  4. Michael Fossenkemper

    Michael Fossenkemper Distinguished past mastering moderator Well-Known Member

    Maybe it does... Maybe it doesn't... in some plugs or boxes. But I think it should. And thanks Ed for making me think about it.
     
  5. Jemvie

    Jemvie Guest

    Well, I resampled the tracks and then lowered the bit-depth and they sound great in my stereo, the sound doesn't fall short to any other officialy released DMB concerts imo (yeah they're Dave Matthews Band songs)

    I tried SRC -> bit-depth reducing first and then bit-depth reducing -> SRC and I couldn't tell any difference but I sticked to SRC -> bit-depth reducing in the end. It just seemed a more logical order to me, I dunno why. My guess is if you resample while the file is still at 24bit the computer has more data to work with and achieve a better resample.

    Then again I could be wrong, ...still, things turned all alright I don't hear anything weird or blatantly forced in the sound.
     

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