Omnia Audio Omnia.9/XE - Manual (Page 99)

The Importance of High Quality Source Audio
There is a saying in the technology world (and in the broadcast plant when it comes to audio) that has
never been truer than it is when applied to streaming audio: “Garbage in, garbage out”.
We have all heard audio streams that sound “swishy” or “underwater”. This is especially true of low-bit
rate encoded streams, but it’s not only the bit rate of the stream that contributes to this sound: It is often
made worse by the source material itself.
Imagine making a copy of an original document on an office copier; the duplicate looks pretty much like
the original, but not quite. Now imagine making a copy from the copy, then another copy from THAT copy,
and so on. Pretty soon you have a document that doesn’t resemble the original at all.
Source audio that has been encoded multiple times (or with poor quality encoders) similarly degrades
with each subsequent encoding. This is called “cascading” data compression.
To put this in an audio perspective, consider that an MP3 file encoded at 128 kbps stereo is usually about
10% of the size of the original, uncompressed, linear audio file. The MP3 files gets to be that small
because the encoder discards an enormous amount of information from the original file. Ideally, the
promise of so-called “lossy” encoders is that it discards only information it determines we won’t miss. The
extent to which this is true is the subject of much ongoing debate, with audio purists on one end who
claim they can hear the tiniest differences (on their $10,000 speakers) and teenagers with iPhones and
cheap earbuds on the other who wouldn’t know good audio if they heard it.
The reality for most listeners is somewhere in the middle, which is why we give recommendations
elsewhere in this manual about the minimum settings for what we consider “broadcast quality” audio.
But one thing is certain: Since streaming audio uses bit-reduced, lossy encoders for the sake of
efficiency in the same way we use these encoders to make manageable music files, using
uncompressed source material is a MUST in our opinion. Neglecting to do so will either result in
audio that has degraded to the point that even the average listening will notice it or being forced to
encode at excessively high bit rates which requires more bandwidth (for you on the server side and your
listeners on receiving side).
Once upon a time, the case could be made for storing a digital music library in a compressed format
because most hard drives were relatively small and the big drives were expensive. At the time this
manual was written, a quality 2 Terabyte external hard drive can be purchased for under $100. What can
you do with 2TB of space? You can store approximately 3,320 hours of 16 bit 44.1kHz linear PCM stereo
audio on it. If you like your information in bite-sized (byte sized?) pieces, that’s nearly 57,000 three-and-a-
half minute songs!
The Importance of High Quality Source Audio
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