High-resolution audio

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High-resolution audio (High-definition audio or HD audio) is a term for audio files with greater than 44.1 kHz sample rate or higher than 16-bit audio bit depth. It commonly refers to 96 or 192 kHz sample rates. However, there also exist 44.1 kHz/24-bit, 48 kHz/24-bit and 88.2 kHz/24-bit recordings that are labeled HD Audio.


Research into high resolution audio began in the late 1980s and high resolution audio content started to become available on the consumer market in 1996. [1]


Approximate dynamic range and bandwidths of some high-resolution audio formats High-resolution audio.svg
Approximate dynamic range and bandwidths of some high-resolution audio formats

High-resolution audio is generally used to refer to music files that have a higher sampling frequency and/or bit depth than that of Compact Disc Digital Audio (CD-DA), which operates at 44.1 kHz/16-bit. [2]

The Recording Industry Association of America (RIAA), in cooperation with the Consumer Electronics Association, DEG: The Digital Entertainment Group, and The Recording Academy Producers & Engineers Wing, formulated the following definition of high-resolution audio in 2014: "lossless audio capable of reproducing the full spectrum of sound from recordings which have been mastered from better than CD quality (48 kHz/20-bit or higher) music sources which represent what the artists, producers and engineers originally intended." [3]

File formats capable of storing high-resolution audio include FLAC, ALAC, WAV, AIFF and DSD, the format used by Super Audio Compact Discs (SACD). [4]


Super Audio CD SACDlogo.svg
Super Audio CD
DVD-Audio DVD-Audio Logo.svg

One of the first attempts to market high-resolution audio was High Definition Compatible Digital in 1995. [5] This was followed by three more optical disc formats claiming sonic superiority over CD-DA: DAD in 1998, SACD in 1999, and DVD-Audio in 2000. These formats offer additional benefits such as multi-channel surround sound. Following a format war, none of these achieved widespread adoption. [6]

Following the rise in online music retailing at the start of the 21st century, high-resolution audio downloads were introduced by HDtracks starting in 2008. [6] [7]

Blu-ray Blu-ray Disc.svg

Further attempts to market high-resolution audio on optical disc followed with Pure Audio Blu-ray in 2009, and High Fidelity Pure Audio in 2013. [8] Competition in online high-resolution audio retail stepped-up in 2014 with the announcement of Neil Young's Pono service. [9]

In 2014 the Japan Electronics and Information Technology Industries Association (JEITA) announced a specification and accompanying "Hi-Res AUDIO" logo for consumer audio products. [10] Sony reaffirmed its commitment towards the development in the high-resolution audio segment by offering a slew of Hi-Res Audio products. [11] [ failed verification ]


Whether there is any benefit to high-resolution audio over CD-DA is controversial, with some sources claiming sonic superiority:

...and with other opinions ranging from skeptical to highly critical:

Business magazine Bloomberg Businessweek suggests that caution is in order with regard to high-resolution audio: "There is reason to be wary, given consumer electronics companies' history of pushing advancements whose main virtue is to require everyone to buy new gadgets." [15]

High-resolution files that are downloaded from niche websites that cater to audiophile listeners often include different mastering in the release  thus many comparisons of CD to these releases are evaluating differences in mastering, rather than bit depth. [16]

Most early papers using blind listening tests concluded that differences are not audible by the sample of listeners taking the test. [17] Blind tests have shown that musicians and composers are unable to distinguish higher resolutions from 16-bit audio at 48 kHz. [18] One 2014 paper showed that dithering using outdated methods [lower-alpha 1] produces audible artifacts in blind listening tests. [19]

A 2007 study showed no audio difference between CD quality audio and higher resolution audio. [17] Joshua Reiss performed a meta-analysis on 20 of published tests, saying that trained listeners could distinguish between hi-resolution recordings and their CD equivalents under blind conditions. [20] Hiroshi Nittono pointed out that the results in Reiss's paper showed that the ability to distinguish hi resolution audio from CD quality audio "was only slightly better than chance". [21]


  1. Rectangular unshaped dither, rather than the industry-standard triangular or shaped dither.

See also

Related Research Articles

High fidelity High-quality reproduction of sound

High fidelity is a term used by listeners, audiophiles, and home audio enthusiasts to refer to high-quality reproduction of sound. This is in contrast to the lower quality sound produced by inexpensive audio equipment, AM radio, or the inferior quality of sound reproduction that can be heard in recordings made until the late 1940s.

MP3 Digital audio format

MP3 is a coding format for digital audio developed largely by the Fraunhofer Society in Germany, with support from other digital scientists in the US and elsewhere. Originally defined as the third audio format of the MPEG-1 standard, it was retained and further extended — defining additional bit-rates and support for more audio channels — as the third audio format of the subsequent MPEG-2 standard. A third version, known as MPEG 2.5 — extended to better support lower bit rates — is commonly implemented, but is not a recognized standard.

Super Audio CD Read-only optical disc for high-fidelity audio storage

Super Audio CD (SACD) is a read-only optical disc format for audio storage, introduced in 1999. It was developed jointly by Sony and Philips Electronics, and intended to be the successor to the Compact Disc (CD) format.

An audiophile is a person who is enthusiastic about high-fidelity sound reproduction. An audiophile seeks to reproduce the sound of a live musical performance, typically in a room with good acoustics. It is widely agreed that reaching this goal is very difficult and that even the best-regarded recording and playback systems rarely, if ever, achieve it.

Sound can be recorded and stored and played using either digital or analog techniques. Both techniques introduce errors and distortions in the sound, and these methods can be systematically compared. Musicians and listeners have argued over the superiority of digital versus analog sound recordings. Arguments for analog systems include the absence of fundamental error mechanisms which are present in digital audio systems, including aliasing and quantization noise. Advocates of digital point to the high levels of performance possible with digital audio, including excellent linearity in the audible band and low levels of noise and distortion.

DVD-Audio DVD-based format for storing audio

DVD-Audio is a digital format for delivering high-fidelity audio content on a DVD. DVD-Audio uses most of the storage on the disc for high-quality audio and is not intended to be a video delivery format.

Audio system measurements

Audio system measurements are a means of quantifying system performance. These measurements are made for several purposes. Designers take measurements so that they can specify the performance of a piece of equipment. Maintenance engineers make them to ensure equipment is still working to specification, or to ensure that the cumulative defects of an audio path are within limits considered acceptable. Audio system measurements often accommodate psychoacoustic principles to measure the system in a way that relates to human hearing.

Direct Stream Digital

Direct Stream Digital (DSD) is a trademark used by Sony and Philips for their system of digitally recreating audible signals for the Super Audio CD (SACD).


The DualDisc is a type of double-sided optical disc product developed by a group of record companies including MJJ Productions Inc., EMI Music, Universal Music Group, Sony BMG Music Entertainment, Warner Music Group, and 5.1 Entertainment Group and later under the aegis of the Recording Industry Association of America (RIAA). It featured an audio layer intended to be compatible with CD players on one side and a standard DVD layer on the other. In this respect it was similar to, but distinct from, the DVDplus developed in Europe by Dieter Dierks and covered by European patents.

High Definition Compatible Digital (HDCD) is a proprietary audio encode-decode process that claims to provide increased dynamic range over that of standard Red Book audio CDs, while retaining backward compatibility with existing compact disc players.

Extended Resolution Compact Disc

Extended Resolution Compact Disc (XRCD) is a mastering and manufacture process patented by JVC for producing Red Book compact discs. It was first introduced in 1995.

Audio bit depth The number of bits of information recorded for each digital audio sample

In digital audio using pulse-code modulation (PCM), bit depth is the number of bits of information in each sample, and it directly corresponds to the resolution of each sample. Examples of bit depth include Compact Disc Digital Audio, which uses 16 bits per sample, and DVD-Audio and Blu-ray Disc which can support up to 24 bits per sample.

Digital eXtreme Definition (DXD) is a digital audio format that originally was developed for editing high-resolution recordings recorded in DSD, the audio standard used on Super Audio CD (SACD). As the 1-bit DSD format used on SACD is not suitable for editing, alternative formats such as DXD or DSD-Wide must be used during the mastering stage. In contrast with DSD-Wide or DSD Pure which offers level, EQ, and crossfade edits at the DSD sample rate, DXD is a PCM signal with 24-bit resolution sampled at 352.8 kHz – eight times 44.1 kHz, the sampling frequency of Red Book CD. The data rate is 8.4672 Mbit/s per channel – three times that of DSD64. DXD also utilizes the vast array of plugins also available to PCM-based digital audio workstations, such as Cubase, Logic Studio, Digital Performer, etc.

Super Bit Mapping (SBM) is a noise shaping process, developed by Sony for CD mastering.

Pono (digital music service) Failed high-resolution audio download service

Pono was a portable digital media player and music download service for high-resolution audio. It was developed by musician Neil Young and his company PonoMusic, which raised money for development and initial production through a crowd-funding campaign on Kickstarter. Production and shipments to backers started in October 2014, and shipments to the general public began in Q1 2015.

HDtracks is a high-resolution digital music store offering DRM-free music in multiple formats as well as cover art with Audio CD-quality and high-definition audio master recording quality download selections.

High Fidelity Pure Audio

High Fidelity Pure Audio, occasionally abbreviated as HFPA, is a marketing initiative, spearheaded by Sony Music Universal Music Group, for audio-only Blu-ray optical discs. Launched in 2013 as a potential successor to the compact disc (CD), it has been compared with DVD-Audio and SACD, which had similar aims.

FiiO X3 Portable Music Player

FiiO X3 is a digital music player manufactured and marketed by FiiO Electronics Technology. The player utilizes Wolfson DAC and is capable of reproducing music sampled at 192kHz with a sample size of 24-bits per channel, and to function as a USB audio interface. The X3 is the mid-level member of the FiiO X Series of portable music players. It supports major lossy music formats, such as MP3 and lossless music formats such as FLAC. According to CNET it is affordable and "terrific sounding" music player. According to LA Times FiiO X3 is a better alternative to an iPod. The player received very positive reviews towards price/sound quality ratio, however it was criticized for inelegant interface and confusing placement of buttons.

Master Quality Authenticated (MQA) is an audio codec using lossy compression and a form of file fingerprinting, intended for high fidelity digital audio streaming media and music download. Launched in 2014 by Meridian Audio, it is now owned and licensed by MQA Ltd, which was founded by Bob Stuart, co-founder of Meridian Audio.


  1. 1 2 Melchior, Vicki R. (2019-05-03). "High Resolution Audio: A History and Perspective". Journal of the Audio Engineering Society. J. Audio Eng. Soc. 67 (5): 246–257. doi: 10.17743/jaes.2018.0056 .
  2. 1 2 Aguilar, Mario (June 2013). "What Is High-Resolution Audio?". Gizmodo. Gawker Media. Retrieved 17 March 2014. High-resolution audio is a new industry marketing term
  3. "High Resolution Audio Initiative Gets Major Boost with New "Hi-Res MUSIC" Logo and Branding Materials for Digital Retailers". The Recording Industry Association of America(RIAA). 2015-06-23. Retrieved 21 August 2018.
  4. 1 2 "High-resolution audio: everything you need to know". What Hi-Fi?. Haymarket Publishing. Retrieved 11 October 2016.
  5. "Home Technology eMagazine - Classic Home Toys Installment #19 The Final CD Format: HDCD". HomeToys. Archived from the original on 2014-03-18. Retrieved 2012-08-05. HDCD is capable of higher quality sound reproduction because HDCD encodes the equivalent of 20 bits worth of data
  6. 1 2 "Definition of:high-resolution audio". PCMag. Ziff Davis. Retrieved 18 March 2014. HDtracks (http://www.hdtracks.com) pioneered high-resolution audio via download
  7. Lander, David (2014-10-21). "Norman Chesky of HDtracks and Chesky Records". Stereophile.com. Retrieved 2019-01-09.
  8. "Universal Music bets on consumer longing for quality with hi-fi Pure Audio". DVD & Beyond. Globalcom Limited. Retrieved 4 January 2014.
  9. O'Malley Greenburg, Zack. "How Neil Young's Pono Music Raised $2 Million in Two Days". Forbes. Retrieved 15 March 2014. He’ll have some competition. Already, services like HDtracks.com have seen triple-digit growth in downloads of top-notch digital files
  10. "Japan Audio Society - Hi-Res Audio Logo". www.jas-audio.or.jp.
  11. "Archived copy". Archived from the original on 2018-12-01. Retrieved 2016-12-29.CS1 maint: archived copy as title (link)
  12. "What are the benefits of SACD?". Mariinsky Label FAQ (Press release). Archived from the original on January 1, 2014. Retrieved January 1, 2014. this album is available to buy on SACDCS1 maint: bot: original URL status unknown (link)
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  14. "24/192 Music Downloads and why they make no sense". Xiph.Org Foundation. Retrieved 21 July 2018.
  15. Brustein, Joshua. "Music Snobs, Neil Young Has a Product for You". BLOOMBERG BUSINESSWEEK. BLOOMBERG L.P. Retrieved 17 March 2014.
  16. "Nine Inch Nails' "Hesitation Marks" - Audiophile, or AudioFAIL ?". Production Advice. 4 September 2013.
  17. 1 2 "Audibility of a CD-Standard A/D/A Loop Inserted into High-Resolution Audio Playback" (PDF). J. Audio Eng. Soc. Retrieved 24 March 2015.
  18. Nicolas Six (21 August 2015). "We tested ... the music in high definition". Le Monde.fr.
  19. Jackson, Helen M.; Capp, Michael D.; Stuart, J. Robert. "The Audibility of Typical Digital Audio Filters in a High-Fidelity Playback System". J. Audio Eng. Soc. Retrieved 9 November 2015.
  20. Reiss, Joshua D. (2016-06-27). "A Meta-Analysis of High Resolution Audio Perceptual Evaluation". Journal of the Audio Engineering Society. J. Audio Eng. Soc. 64 (6): 364–379. doi: 10.17743/jaes.2016.0015 .
  21. Hiroshi Nittono (2020). "High-frequency sound components of high-resolution audio are not detected in auditory sensory memory". Scientific Reports. Nature. 10 (1): 21740. Bibcode:2020NatSR..1021740N. doi:10.1038/s41598-020-78889-9. PMC   7730382 . PMID   33303915.