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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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