Audio Myths

Dispelling common misconceptions and misleading truths
Spring 2019 - Audio Tech Talk Series
February 19, 2019

Condenser microphones “pick up” more of the room than dynamic microphones

Neumann TLM 103

Condenser

Shure SM58

Dynamic

Polar Patterns

Neumann TLM 103

Condenser

Shure SM58

Dynamic

Frequnecy Response

Condensers “pick up” more of the room than dynamics

False

You can hear high-resolution audio

What is high-resolution audio?

Music files that have a higher sampling frequency and/or bit depth than that of Compact Disc Digital Audio, which is specified at 16bit/44.1 kHz.

From the high resolution audio page on Sony.com

From the high resolution audio page on Technics.com

Digital audio does not contain stairsteps

Sampling rate only affects bandwidth
(highest frequencies)

Bit depth only affects dynamic range
(noise floor)

16 bit vs. 24 bit (96 dB vs. 144 dB)

44.1 kHz vs. 96 kHz (22.05 kHz vs. 48 kHz)

Support of high-resolution audio

Criticism

  • "If they [the music business] cared about sound quality in the first place, they would make all of the releases sound great in every format they sell: MP3, FLAC, CD, iTunes, or LP." — cnet

  • "Impractical overkill that nobody can afford" — Gizmodo

  • "A solution to a problem that doesn't exist, a business model based on willful ignorance and scamming people." — Xiph.org

You can hear high-resolution audio

Mostly false

MP3 audio sounds bad

What is mp3 audio?

MP3 compression works by reducing (or approximating) the accuracy of certain components of sound that are considered to be beyond the hearing capabilities of most humans. This method is commonly referred to as perceptual coding or as psychoacoustic modeling.

Temporal Masking

Listening Examples

uncompressed WAVE - 2.5 MB

320 kbps MP3 - 563 KB [x4.4 factor] - Fs = 44.1 kHz

128 kbps MP3 - 225 KB [x11.1 factor] - Fs = 44.1 kHz

96 kbps MP3 - 169 KB [x14.8 factor] - Fs = 44.1 kHz

16 kbps MP3 - 29 KB [x86.2 factor] - Fs = 8 kHz

MP3 audio sounds bad

Mostly false

Power conditioners will
improve sound quality

Furman PL-8 Power Conditioner

$200.00

Furman M-8x2 Power Conditioner

$100.00

AudioQuest Niagra 7000

$7999.50

AC-DC Power Supply

Power conditioners will
improve sound quality

Mostly false

Cables improve sound quality

How expensive could cables be?

Very

Moon Audio - Sliver Dragon XLR interconnect

$500

Cardas - Clear Beyond Speaker Cable

$6,840

Siltech Cables - Emperor Double Crown Speaker Cable

$45,000

Transmission Line Theory

'Short' vs. 'long' connections

Speed of light - 299,792,458 m/s

100 ft. (~30.5 m) audio cable - 101 ns propagation delay

20 kHz -> T = 50 μs and ~10,000 m wavelength in copper

"Cables connecting an audio amplifier to speakers would have to be over 1.55 miles in length before line reflections would significantly impact a 20 kHz audio signal"

What matters in a cable?

  • Connectors - well made for good contacts

  • Cable insulation - durable

  • Correct gauge for application

Cables improve sound quality

Mostly false

Next Talk - March 5

AI in Audio

Part I: Automated music generation and production