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Thread: Digital equalization/audio degradation

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    Digital equalization/audio degradation

    Hello,
    I'm playing FLAC-encoded music through a laptop, using its optical output connected to a DAC. I use Winamp and Shibatch Super Equalizer (incorporates 16383th order FIR filter) to correct room modes. Am I being right that this kind of equalization does not make sound quality any worse? After all, everything is done digitally and the EQ is very accurate. Could there be any bottleneck in this setup?

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    Senior Señor boputnam's Avatar
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    Quote Originally Posted by lofi-ear View Post
    ...(incorporates 16383th order FIR filter)...
    I have no idea what that is, but I want it...

    That "Super EQ" offers more filters than the normal Winamp EQ - that's why it is "better". But it is still only a 1/2 octave EQ. Winamp's EQ has some other problems (as noted on various websites) and is only an approx. 1 octave EQ - that alone is undesireable.

    Quote Originally Posted by lofi-ear View Post
    After all, everything is done digitally and the EQ is very accurate.
    Filter accuracy is one thing; distortion to phase is quite another...
    bo

    "Indeed, not!!"

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    RIP 2013 Rolf's Avatar
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    Quote Originally Posted by lofi-ear View Post
    Hello,
    I'm playing FLAC-encoded music through a laptop, using its optical output connected to a DAC. I use Winamp and Shibatch Super Equalizer (incorporates 16383th order FIR filter) to correct room modes. Am I being right that this kind of equalization does not make sound quality any worse? After all, everything is done digitally and the EQ is very accurate. Could there be any bottleneck in this setup?
    There is no way one can get the same quality from a computer, as you can get from a good CD player. And I mean a CD player, not a player that can play CD, DVD, MP3, picture viewing .. or whatever it can play. Use a CD player that only plays CD's.

    One can get an "All playing Unit", but I don't think you want to pay the price.

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    Quote Originally Posted by Rolf View Post
    There is no way one can get the same quality from a computer, as you can get from a good CD player.
    But as long as the signal is digital what difference does it make? I think computer is the best digital audio source, since reading bits from a spinning disc could be a precarious process..

    It looks like a fir filter does not distort phase, so maybe there's not much to worry about. If there were better EQ's than the shibatch one I'd gladly like to know about them.

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    Senior Member Ducatista47's Avatar
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    Quote Originally Posted by lofi-ear View Post
    But as long as the signal is digital what difference does it make? I think computer is the best digital audio source, since reading bits from a spinning disc could be a precarious process..
    A hard drive is a spinning disk that bits are read off of. Just not optically, like a disc spelled with a "c" a la Phillips.

    You never know until you hear for yourself what something digital is going to sound like. When you burn a disc from a no loss compression source on the fly it should sound the same as burning after decoding, but it does not sound the same to me. There is a difference in fidelity that an excellent playback system will reveal.

    Likewise, an analogue master does not sound like a digital master. Who can say why, but it is easy to hear the difference. Ears trump specifications every time, since we have to use them to hear anything.

    Clark
    Information is not Knowledge; Knowledge is not Wisdom
    Too many audiophiles listen with their eyes instead of their ears


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    RIP 2013 Rolf's Avatar
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    Quote Originally Posted by Ducatista47 View Post
    A hard drive is a spinning disk that bits are read off of. Just not optically, like a disc spelled with a "c" a la Phillips.

    You never know until you hear for yourself what something digital is going to sound like. When you burn a disc from a no loss compression source on the fly it should sound the same as burning after decoding, but it does not sound the same to me. There is a difference in fidelity that an excellent playback system will reveal.

    Likewise, an analogue master does not sound like a digital master. Who can say why, but it is easy to hear the difference. Ears trump specifications every time, since we have to use them to hear anything.

    Clark
    Exactly. The same digital music signal does not sound the same with different sources. The best sounding is from an original CD. The signal is on the original CD printed, not burned.

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    Heather [Senorita member] hjames's Avatar
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    Quote Originally Posted by Rolf View Post
    Exactly. The same digital music signal does not sound the same with different sources. The best sounding is from an original CD. The signal is on the original CD printed, not burned.
    And where do you think the data that is "printed" to the CD comes from?
    Its from digital sources - on hard drives and such!

    The real thing is to be sure no downgrade or translation to lower bit rate occurs when the digital file is copied - THATS what bites most folks when they rip CDs to their hard drives ...

    That and, as Scott mentioned, the converter chips used for playback ...
    2ch: Oppo, Acurus RL-11, JBL 240ti, Heath AS101, Carver TFM-25,Von Schweikert VR4
    7: Oppo BDP103D, B&K, UREI 809A, JBL B460,

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    RIP 2013 Rolf's Avatar
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    Quote Originally Posted by hjames View Post
    And where do you think the data that is "printed" to the CD comes from?
    Its from digital sources - on hard drives and such!

    The real thing is to be sure no downgrade or translation to lower bit rate occurs when the digital file is copied - THATS what bites most folks when they rip CDs to their hard drives ...

    That and, as Scott mentioned, the converter chips used for playback ...
    I have not been in a studio for years, so I can't tell you witch media the recording is stored. After what I have read on the net most use a digital tape recorder. Remember, in a studio the signal comes directly from the source.

    This is not my point. There is a difference in printing a cd vs burning a cd. They do not sound the same. Don't ask me why, it is just what I can hear when playing a direct copy of a cd vs the original. The same with playing from a computer, squeeze box or whatever media.

    Yes, converters do things differently. That is one reason why cd players sound different. Other things are error correction circuit , the drive gear? (not sure if this is the correct word in English). This is why a expensive cd player (up to a point) sound better than a cheaper one.

    EDIT: In the "old days" with just analog recordings, you do know that the original master tape sounds better than the LP?

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    Well, moving parts are moving parts. Tape deck, CD transport, turntable, computer hard drive--all have latency, flutter, reading/tracking errors, etc. Sure the specs are better on some than others, but moving parts are moving parts.

    Now that solid state storage is coming into its own, it can eliminate the weak link of moving parts, and the errors and latency problems become a magnitude of order smaller. Perfect? No, but much closer to perfect as it becomes a mature technology.

    Combine instantaneous transfer with the next generation of DACs and OpAmps, and you're not in Kansas anymore, Toto.

    Star Trek may have had it right. Drop in a ceramic or crystal chip and there's a universe of uncompressed data or sound right there.
    Out.

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    Senior Señor boputnam's Avatar
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    Quote Originally Posted by Ducatista47 View Post
    ...When you burn a disc from a no loss compression source on the fly it should sound the same as burning after decoding, but it does not sound the same to me. There is a difference in fidelity that an excellent playback system will reveal.
    Hi, Clark...

    Your post challenged my experience and memory - it cause me to research two old threads on the topic: Both the "uploading music library suggestions" and the "Anyone had experience with Squeezebox" threads dig pretty deep into the topic.

    In both these, Don took many to task with his research and experiences. It got me to challenge and test my own slant, so-much-so that lately I've gone to FLAC file type for live recording on my SoundDevices 722. I cannot tell any loss of quality whatsoever.

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    Senior Member Ducatista47's Avatar
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    Hi, Bo,

    There are two things at work here. Firstly, as usual, there is always the possibility that I am full of crap. If I am not, I should clarify that I meant to allude to decoding errors, not any degradation due to FLAC encoding. I agree that FLAC is the best storage tool I have ever worked with. I like it better than Wavpack, and wv better than APE. My prejudices, I can't defend them.

    Where I either really did hear differences or imagined them was in burning back to full audio files. When I compared CD's I burned from FLAC on the fly to those from the same files when I first decoded the FLAC and then burned in two distinct processes. I attribute any degradation I think I hear to the burning software's native decoding abilities being inferior to the stand alone FLAC tools handling of the task.

    From Don:
    I'm not sure if it is clear, but lossless compression has all of the benefits of .wav files but at half the space. When played back, the file is uncompressed and becomes a bit for bit equivalent of the .wav file from which it was created. If need be, you can burn the files back to a CD in .wav format and they will be exactly the same as the original.
    I always took this as gospel, but now I am not so sure. At this point I think there is room for theory and practice to diverge. Software and/or hardware could be at fault.


    I would think computer based burning software would lack accuracy/abilities as compared to professional decoding or encoding hardware like your 722 in any case. The only question - is the difference audible? What I think I hear is not digital errors of the gross kind, but lower fidelity, a less smooth rendering of the music. Like a typical American CD vs the Japanese product (with Obi) of the same recording, but more subtle. It is also possible that it is a burn issue, but I burn at the lowest available rate and use data verification. One would think that would be sufficient to guarantee accuracy, so I am probably all wet.

    I should add that I never use a computer or portable music system for playback or music library work. I will probably never have any need for digital storage of music in any form other than CD's and DVD's. I am more or less incapable of casual listening.

    Clark, always open to correction
    Information is not Knowledge; Knowledge is not Wisdom
    Too many audiophiles listen with their eyes instead of their ears


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    Super Moderator jblnut's Avatar
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    For the curious and open-minded, there is some great info on this website. I'm not taking sides here, as I've mostly decided that LP's sound superior to CDs on my equipment in my room. Your mileage may vary of course...



    http://www.computeraudiophile.com/

    jblnut

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    Senior Member Ducatista47's Avatar
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    Here is a basic question. When burning software verifies written data, and the FLAC (or Wavpack or APE or mp3) file has been decoded on the fly during the burn, is the written data being compared to a metafile, the FLAC, the results of the decoding, or what?

    In other words, if the decoding process produces errors, it is still the output of the decoding that is being verified since the uncompressed source is not available for comparison? I don't know what else there would be to compare to. If this is so, then data verification could not spot decoding errors.

    This would also apply, I believe, to music servers playing compressed files. Unless there is a check sum type verification going on during decoding. I think maybe ordinary CD playback does this?

    Clerk
    Information is not Knowledge; Knowledge is not Wisdom
    Too many audiophiles listen with their eyes instead of their ears


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    RIP 2013 Rolf's Avatar
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    Quote Originally Posted by Ducatista47 View Post
    Here is a basic question. When burning software verifies written data, and the FLAC (or Wavpack or APE or mp3) file has been decoded on the fly during the burn, is the written data being compared to a metafile, the FLAC, the results of the decoding, or what?

    In other words, if the decoding process produces errors, it is still the output of the decoding that is being verified since the uncompressed source is not available for comparison? I don't know what else there would be to compare to. If this is so, then data verification could not spot decoding errors.

    This would also apply, I believe, to music servers playing compressed files. Unless there is a check sum type verification going on during decoding. I think maybe ordinary CD playback does this?

    Clerk
    Interesting question. Since I really don't know all of this, this is my 2c about this.

    If you make a direct copy of a CD, the program first store the files on the hard drive, then make a copy on a CD-R. In this case I believe the program can compare the original CD with the copy on the hard drive. If the original and the copy are in a certain range for errors (guess it depends on what the programmers of the program has decided what is acceptable) it will be burned on the CD-R.

    Why the burned copy does not sound as good as the original MUST have to do with printing vs burning.

    In the second example that is if the original CD is is transferred directly from the CD's original files, decoded to f.ex. FLAC, there is nothing to compare, as the format of the files are different.

    Then, if one is downloading files in FLAC or other decoded formats, there is no way to be sure how good the copy is, and that is probably why I have heard that music copied this way sound terrible.

    When you play a original CD in your CD player, the error correction circuit will correct the errors +- ? %. Some CD players accept more errors that others. As a general rule on can say that a less expensive player allows more errors than an expensive one. But all players have a limit, and at a certain point the disk is unusable.

    Here are some "facts" I have picked up along the way:

    Note is that the more errors needed to be corrected, the more bad the sound. That is why most CD's today sound terrible. Not enough care is taken in production, where ever in the line the "bad things" happen.

    If the digital signal always are 100%, the error checking would not be needed. Reality is most CD's have a lot of errors, making them sound bad.

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