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High-Resolution Audio: The Next Generation? Or Fake News?

While lossless media streaming services and advance digital audio playback systems proliferate, audiophiles maintain their reverence for analog sound sources.

High-resolution audio (HRA) is gaining strength as the audiophile-preferred format for music recording and playback. While its acceptance and use promise to revitalize a multimillion-dollar market, there remains confusion as to how the standard is defined and what distinct advantages it offers over “CD Quality.”

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How we feel about the music we play may be tainted by the knowledge about the music files available to us. The bulk of our music files are compressed to minimize the storage space required, and the width of the data pipes enabling download from the Internet. Does that fact trigger a prejudice about what we hear when we listen carefully to a music source? One argument suggests there are noticeable differences in sound quality between high-resolution audio and current-generation Compact Audio Discs (CDs)—and this difference is discernible to even the most casual audio listener. At the other side of the discussion, listeners may question the value of HRA, as human hearing does not extend much beyond 20 kHz; most adults, in fact, do not hear much beyond 11,000 hertz. An extreme form of this argument—the audiophiles’ version of “Fake News”—insists HRA is a hoax intended to spur the market for overpriced music download services.

“A DSP can model an audio stream sampled at 5.1 MHz—roughly 256 times greater than Nyquist.”

Can High-Resolution Audio Be Heard?
In principle, high-resolution audio recordings use a much higher bit resolution and sampling frequency to record analog audio and convert it to digital. Compared to standard CDs, recorded with a bit resolution of 16 bits and a sampling rate of 44.1 kHz, HRA files use a sampling frequency of 96 kHz or 192 kHz at 24 bits.

While the sample rate refers to the number of times per second, an analog-to-digital converter captures slices of the audio analog waveform; the bit rate refers to how much “bits of data” each of the slices contains. The bit rate of the sampling for Compact Audio (CD) discs is 16 bits; that is, each audio sampled sliver is converted to digital bit words, and that word is divided into 16 bits. The bits represent 2n slices of the bit pattern, some 65,536 of them, where n represents the number of bits (16), or 16.8 million of them (with n=24 bits). The 16- or 24-bit slivers divide up the amplitude of the recorded audio signal. The higher the bit rate, HRA advocates believe, the greater resolution of the sound you will hear.

There is on-going debate as to whether listeners discern the difference in bit rate. It could expand the sound stage for orchestral music in a 3D sound space. Alternatively, it could be inaudible. A June 2016 Audio Engineering Society (AES) paper suggests that ordinary people—not just Golden Ears critics—can hear the difference between compact discs and high-resolution playback. Test subjects were asked, does it make a difference? Conclusions where a “soft” yes: untrained, a small proportion of respondents did respond to it. A greater “yes” response was obtained when the listeners were “trained” what to listen for. However, that also introduced the concern as for whether the differences were psychosomatically induced. That is, respondents believed they could hear differences and consequently did.

An Opening for Hi-Res Service Providers
Media streaming services (rather than HiFi equipment makers) appeal to listeners looking for (free, lossless audio codec (FLAC) files to play on their smartphones or dedicated MP3 players. The existing streaming services offer higher bit rates; some are promoting “HiFi’ with higher subscription costs. A sampling of FLAC file vendors includes the following:

Spotify, which is preparing to launch a hi-resolution streaming service, to supplement its monthly $9.99 service. Spotify allows listeners to stream “normal” quality audio (96kbps), “high” quality (160kpbs) and “extreme” quality (320kbps).

Tidal is promoting a “lossless” streaming service for the iOS or Android mobile operating systems. Its “premium” service costs $9.99 per month and offers 320 kbps streaming. Tidal’s Apple-compatible service offers a bit-rate improvement over iTunes 256 kbps bit stream. Tidal promises access to a “Hi Fi Master,” with 30,000 available tracks (read “Songs”) with Master Quality Authenticated (MQA) encoding.

Qobuz, a French company offers a “CD Quality” Service that streams at 320 kbps (for $9.99 per month). Its “hi-fi” service rents for $19.99 per month, is specified at 24-bit/192kHz for Android or iOS devices but demands an up-front annual subscription payment.

Yet one more, Deezer, promises lossless streaming of 43 million available tracks for $9.99 per month.

Pay Most Attention to the Source Material
The proliferation of digital audio playback systems obscures the reverence audiophiles still maintain for analog sound sources. As with many things audio, it could be perceived as a religious sentiment: that analog audio, without digital artifacts, provides the best sound quality. It serves as the reference for evaluating sound quality.

High resolution/high-speed data converters and digital signal processors (DSPs) using delta-sigma conversion processing effectively replace amplitude sampling in modern recording studios. A DSP can model an audio stream sampled at 5.1 MHz—roughly 256 times greater than Nyquist. The DSP effectively exchanges time sampling for amplitude sampling. With digital processing, the recording hardware can effectively extract 24-bits—over 16 million slivers. This contributes to the reproductive “authority” of the recording, even if the boost in its audio sound quality is not immediately obvious. Enthusiasm for high-resolution audio, experts advise, should be tempered concerning its source.


Photo-RudyRamos_webRudy Ramos is the project manager for the Technical Content Marketing team at Mouser Electronics and holds an MBA from Keller Graduate School of Management. He has over 30 years of professional, technical and managerial experience managing complex, time critical projects and programs in various industries including semiconductor, marketing, manufacturing, and military. Previously, Rudy worked for National Semiconductor, Texas Instruments, and his entrepreneur silk screening business.

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