
Simple?
Audio playback once seemed as
simple as placing a record on a turntable and engaging the
play button. But 20th century memories can be
short.
It wasn't always that simple. For example, the playback
of a vinyl record could include several sizes in one of four
speeds. And prior to 1954 vinyl enthusiast confronted
several playback equalization choices. In addition,
audio tape formats such as the open reel or cassette included
options such as tape size, speed, noise reduction, playback
equalization, and recording bias.
Given this history, it shouldn't
be surprising that the 21st digital century has also generated
yet another collection of audio options wrapped in terms such
as
file and format, compressed or uncompressed, lossless or
lossy, WMA, ACC, MQA.
Files & Formats

Digital audio organizes data into
files and formats. The file is the container. The
format is the storing method.
For example, the compact disc files audio to an optical discs
and uses the Sony/Phillips 16-bit 44.1KHz sampling rate
format.
Digital audio can also be filed to a music server hard drive,
solid state drive, or streamed from an Internet cloud
server.
This type of audio file management must choose between a
compressed or uncompressed format.
Uncompressed Format
An uncompressed format records
the entire audio waveform.
But this format also devours computer storage and Internet
bandwidth.
Uncompressed formats include FLAC, WAV, AIFF, and DSD formats.
Handbook
Note: Codec is shorthand for encode/decode
Compressed Format
A compressed format saves
computer storage and bandwidth. It shrinks data files by
removing "unneeded" data with masking codec software.
Masking records louder lower frequency audio while removing
less loud higher frequency audio data of the same phase. The
missing audio data is said to go unnoticed because its loss is
hidden or masked by the louder audio. There are two
versions of compressed formats, lossless and lossy.
Lossless
Lossless compression reduces
data and data storage by 50%. Lossless can compete with
or improve CD quality audio. Lossless lost redundant
data can be less damaging than CD optical-laser jitter-phase
distortion. Popular lossless formats include ALAC and
FLAC.
Lossy
Lossy compression reduces data and data storage by 90%.
But lossy does not approach CD quality audio. Lossy
audio quality ranges from a cell phone to good FM radio.
MP3, ACC, WAV, OGG are popular lossy formats.
Masking Comment
Masking implies that the lost redundant audio data is
insignificant. However, that data includes essential
HiFi phase information. Sound engineers have proven that the
human ear is more sensitive to phase than frequency. A
friend once explained it was more important for early caveman
to determine which direction (phase) a tiger was coming from
than which tiger (frequency). We are descendants of the
former.
Phase distortion is a well know issue in high fidelity
circles. Phase distortion has long been identified as a
key-hindrance to compact disc fidelity. Masking can also
create audible phase distortion. Check out The Absolute
Sound MQA story "
Musical Origami". Bob
Stuart of Meridian introduced a digital audio format that
eliminates phase distortion.
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