Skip navigation
WilliamTael
Currently Being Moderated

Basics about digital audio

Aug 29, 2013 2:22 AM

Tags: #audio #basic

I always wanted to know what means terms like:

 

44100hz

48000hz

Lossy

Sample rate

Bit rate

Bit Depth

 

The more detailed your answer is, the better.

 
Replies
  • SteveG(AudioMasters)
    5,602 posts
    Oct 26, 2006
    Currently Being Moderated
    Aug 29, 2013 2:45 AM   in reply to WilliamTael

    WilliamTael wrote:

    The more detailed your answer is, the better.

     

    So this is 'please tell me everything you know about...' is it?

     

    With the best will in the world, we can't do that - it's far too time-consuming, and Google will easily provide you with answers to some of it. Yes I know that this doesn't differentiate between what's good and bad (and there is definitely some bad). So in an effort to guide you a little in approximately the right direction, try these:

     

    http://www.indiana.edu/~emusic/etext/digital_audio/chapter5_digital.sh tml

    http://en.wikipedia.org/wiki/Audio_bit_depth

    http://en.wikipedia.org/wiki/Lossy_compression

     
    |
    Mark as:
  • Currently Being Moderated
    Aug 29, 2013 4:27 AM   in reply to WilliamTael

    Steve is right that this is not the sort of thing that can be explained in a paragraph or two on a help forum.  Entire books have been written giving detailed answers to your questions.

     

    However, to help set you in the right direction as you read the (very good) sites Steve has suggested:

     

    First, 44,100 and 48,000 are sample rates (like your fourth question).  That the number of times per second you audio is sampled by the device converting your analogue sound to digital.  Those two numbers are very common in the digital audio world because 44,100 is the sample rate used for CDs and 48,000 is commonly used for video work. 

     

    Lossy (as opposed to lossless) describes a type of compression.  MP3 is lossy because the coding algorithm "throws away" permanently changes your digital audio file by filtering off certain high frequencies that most people can't hear and by using psycho acoustic techniques to leave out a lot of the actual information in a way in a way that's not TOO noticeable by the human brain.  Once it's gone, however, the information can never be recreated, hence the term lossy.  Lossy compression is capable making files a LOT smaller.  Lossless compression (for example FLAC) uses techniques that don't permanently lose any information so the file can be completely restored.  However, the resulting compressed files tend to be larger than on a lossy system.

     

    Bit depth is how many bits (i.e. zeroes and ones) that define the audio each time it's sampled.  At 16 bit, you have that number of zeroes and ones which equates to 65,536 different levels of audio that can be defined.

     

    Bit rate is a measure of how big an audio file is for calculation storage or data transmission...the bit rate is the sample rate times the bit depth.

     

    As you can see, even keeping it at its simplest, this is a topic that needs lots of detail for a real answer, hence Steve's links.

     
    |
    Mark as:
  • Currently Being Moderated
    Aug 30, 2013 2:30 AM   in reply to WilliamTael

    There used to be a very useful Digital Primer as part of Audition 1.5's user manual. see Appendix B in the following pdf.

     

    http://www.enloeaudio.com/uploads/7/1/0/7/7107552/adobe_audition_1.5_m anual.pdf

     
    |
    Mark as:
  • SteveG(AudioMasters)
    5,602 posts
    Oct 26, 2006
    Currently Being Moderated
    Aug 30, 2013 2:18 PM   in reply to ryclark

    Also, you might want to look at Charles VW's good video (the one he found - he's not in it!) - and possibly some of the others in the series, especially if they're as good as this one:

     

     
    |
    Mark as:

More Like This

  • Retrieving data ...

Bookmarked By (0)

Answers + Points = Status

  • 10 points awarded for Correct Answers
  • 5 points awarded for Helpful Answers
  • 10,000+ points
  • 1,001-10,000 points
  • 501-1,000 points
  • 5-500 points