Digital Music
Part 2
Understanding
From the Kindle book
Understanding Digital Music
Disc-based Music
Variety of formats provide the best possible fidelity for music — Streaming music and digital downloads
don’t even compare
Includes standard compact discs and many other formats — CDDA (Compact Disc Digital Audio)
— SACD (Super Audio Compact Disc)
— DVD-A (DVD-Audio)
— Blu-ray Audio
Sampling Rate & Bit Rate
Sampling rate (or sample rate) and bit rate indicate fidelity
Higher numbers = better fidelity — Controversial whether humans can hear an improvement
Music is inherently continuous analog sound waves — Analog sound waves are captured as digital data — Bits and bytes; ones and zeroes
Sample rate = how many times per second a chunk of music is digitally captured
Bit rate = the size of the digital chunk — Number of bits captured with each sample
Sampling Rate
Sampling rate is indicated as hertz (Hz) —Hertz = cycles per second
—In the case of music, data captures per second
Audio discs feature sampling rates in the tens of thousands of hertz —For digital music, hertz denoted as kilohertz (kHz)
—Most common sample rates are 44.1 kHz to 192 kHz
—Standard compact discs (CDDA format) = 44.1 kHz
Bit Rate
“Thickness” of the data slice captured with each sample
— Think of lunch meat from the deli
— Amount of data, or bits, that is actually captured in the sample
Like sampling rate, higher bit rates = better fidelity
— Again, controversial if humans can hear improvement
Rates are either 16-bit or 24-bit
Down with Bits & Bytes Let’s get some perspective about bits, bytes,
and data sizes Eight bits = one byte A million bytes = one megabyte (MB) A billion bytes = one gigabyte (GB) Megabytes (measure for data and file sizes) are
denoted as MB (upper case “B”) Megabits (how internet bandwidth and network
speeds are measured) are indicated as Mb (lower case “b”)
Formats Overview
Standard compact discs —CDDA format: Compact Disc Digital Audio
—Lowest sampling rate and bit rate
—Lowest storage capacity (shortest playback time)
Super Audio Compact Disc (SACD) —High-resolution music format
—High sampling rate and bit rate
—Second highest storage capacity of high-res formats
Formats Overview
DVD-Audio (DVD-A) —High-resolution music format
—High sampling rate and bit rate
—Better-than-CD storage capacity, but only half of SACD capacity
Blu-ray Audio —High-resolution music format
—High sampling rate and bit rate
—Highest storage capacity of high-res formats
Compact Disc Digital Audio
Introduced in 1980 by Sony and Philips
Sampling rate: 44.1 kHz
Bit rate: 16-bit
Storage capacity: 80 minutes
Limited to two-channel music
—No surround sound
Lowest fidelity disc-based format, but still several times better than MP3 and AAC
Super Audio Compact Disc
Introduced in 1999 by Sony and Philips — Intended to be successor to standard CDs
Sampling rate: 2.8 mHz
Bit rate: 24-bit
Storage capacity: 256 minutes — Great for long concerts, symphonies, etc.
Capable of storing 5.1 surround sound — But most albums on SACD are only stereo
Roughly 2-3x the cost of CDDA discs ($20-30)
DVD-Audio
Introduced in 2000 by the DVD Forum —The Guardian called DVD-A “extinct” by 2007
Sampling rate: 44.1-192 kHz (variable)
Bit rate: 24-bit
Storage capacity: 256 minutes
Capable of storing 5.1 surround sound —Most albums on DVD-A are only stereo
Roughly 2-3x the cost of CDDA discs ($20-30)
Blu-ray Audio Introduced in 2013 Piggy backs on the popular Blu-ray video format
— Playable in any Blu-ray player (even cheap ones)
Sampling rate: 96-192 kHz (variable) Bit rate: 24-bit Stores three versions of uncompressed audio
—PCM digital, Dolby TrueHD, and DTS-HD Master Audio —All other high-res music formats are compressed
Capable of storing 5.1 surround sound Average price $20-30 (2-3x the cost of CDDA)
Hybrid Discs
Single disc on which both a high-res and a standard (CDDA) version of an album or concert are stored — Hybrid discs never contain two high-res formats
Can be played in legacy equipment (like car CD players) in addition to home theaters — This makes these discs backward compatible
— Very practical
Like SACD, DVD-A, and Blu-ray Audio, more expensive than CDDA
Player Compatibility
Most CD players, DVD players, and Blu-ray players don’t handle SACD or DVD-A formats
Standard CD and DVD players can’t play any Blu-ray discs (audio or video)
Entry-level Blu-ray players guaranteed to not handle SACD and DVD-A
Universal players are those that can play all high-resolution formats —More expensive
Tommy, Can You Hear Me?
Don’t fool yourself; some people can’t hear the difference between CDDA and high-res formats
2007 study by Audio Engineering Society claims subjects couldn’t perceive difference between CDDA and high-res formats like SACD or DVD-A
If you have to strain or think too hard to hear an improvement…. — It’s a waste of money
— You’re better spending your cash on better gear
— Better gear = any disc, including CDDA, sound better
Wrap Up Biggest advantage of high-res formats = 5.1 surround
sound
SACD and DVD-A formats bombed with consumers — But still available
— About 6,000 SACD titles (more than DVD-A)
Before spending big bucks on expensive high-res discs, test listen
Compare CDDA with a high-res format —Preferably with your own equipment
Not worth spending more money on a universal Blu-ray player if you can’t hear an improvement
These slides are derived from the Amazon Kindle book
Understanding
Digital Music
Other Books by Curt Robbins
Home Theater for the Internet Age
Understanding Cutting the Cord
Understanding Personal Data Security
Understanding Home Theater
About Curt Robbins
Blog: Middle Class Tech
Flipboard magazine: Middle Class Tech
Twitter: @CurtRobbins
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