High-resolution audio is a popular buzzword in the world of streaming and audio file formats more generally. Streaming services are increasingly advertising this as the next big advancement in digital audio, with hardware manufacturers releasing headphones and music players marketed to be capable of ‘Hi-Res Audio'.
Do High-Resolution (Hi-Res) audio files make a difference? Hi-Res audio formats are objectively better than CD quality regarding their technical specifications, namely sample rate and bit depth. High-resolution audio may make a difference to trained ears through high-end Hi-Fi systems. For most consumers, it's more so marketing than an audible upgrade.
S what does High-Resolution audio actually mean? How does it compare to the audio format we're already using? Is it worth upgrading your hardware to harness Hi-Res audio? Should you export your audio projects in a High-Res format? That's what we'll explore in this article, answering the key question: do High-Resolution (Hi-Res) audio files make a difference?
What Is High Resolution (Hi-Res) Audio?
Unlike other HD standards like High-Definition video, there is no universally agreed standard for Hi-Res audio. Therefore, the exact specifics of Hi-Res audio can vary between implementations. Instead, the Digital Entertainment Group in 2014 defined High-Resolution as:
“lossless audio that is capable of reproducing the full range of sound from recordings that have been mastered from better than CD quality music sources”.
However, generally, the ‘High-Resolution' label in audio refers to the sample rate of the file and bit depth. More specifically, the label is associated with better audio than CD quality (which has a 44.1 kHz sample rate and a 16-bit bit depth).
Sample Rates Of “Hi-Res” Audio
We must first dive into how digital audio works to understand what this means. When an analog sound signal is converted into a digital file, an encoder takes a series of snapshots called samples. If these snapshots are played in quick succession, this accurately represents the original sound wave.
Furthermore, when it comes time to convert the digital audio to analog audio for playback (speaker and headphone drivers require the alternating current of analog audio), the samples are [ideally] converted into a smooth electrical waveform.
As digital files are made up of binary digits – 1's or 0's – digital audio requires a discrete-time signal as opposed to the continuous nature of analog sound waves. Therefore, digital audio is always an approximation of the original sound subject to the number of snapshots taken.
A sample rate – also known as the sampling frequency – is the resolution of these samples. This is measured in kilohertz (kHz) or ‘thousand times per second'.
Samples rates have two effects: it theoretically increases the accuracy of the digital representation of the original file. It also determines the range of frequencies that can be captured in digital audio.
The sample rate of CD-quality audio is 44.1 kHz. Why such a seemingly arbitrary frequency? Due to a phenomenon known as the Nyquist frequency, digital audio can reproduce frequencies at up to half its audio sample rate. This is because the sampling must be able to, at a minimum, capture the high point and the low point of the wave's frequency.
The range of frequencies the human ear can make out is 20 Hz and 20 kHz – and so 44.1 kHz neatly recreates all the possible sounds we could hear.
The Nyquist-Shannon sampling theorem essentially states that, in order to avoid aliasing, a digital sampling system must have a sample rate at least twice as high as that of the highest audio frequency being sampled.
Note that, if aliasing were to occur, frequencies above the hearing range would cause distortion and artifacts in the hearing range.
So with a sample rate of 44.1 kHz, the audio signal's highest frequency is at 22.05 kHz or 22,050 Hz. This gives a small range of frequencies to roll-off frequencies between 20 kHz and 22.05 kHz with a low-pass filter.
Bit Depth Of “Hi-Res” Audio
Conversely, bit depth is the number of bits available for each sample. Therefore, the greater the number of bits, the higher the quality of each audio sample. This primarily concerns the accuracy of the audio file.
The victims of low bit depth are often quieter sounds, as low bit depth leads to lost frequencies. Higher bit depth also allows audio files to be louder. A 1-bit increase in bit depth leads to the dynamic range – the difference between the quietest and loudest sounds in a mix – increasing by about 6 decibels.
CD-quality audio has a bit depth of 16-bits. This usually increases to 24-bits for DVD audio.
That brings us to High-Resolution audio. Hi-Res audio tends to have samples rates and bit depths exceeding that of CD audio. As a reminder, that's a sample rate of 44.1 kHz and a bit depth of 16-bits.
High-Resolution audio files typically use a sampling frequency of 96 kHz or 192 kHz at 24 bits. The most common High-Resolution audio format is the lossless standard FLAC. The format used for Tidal Master Hi-Res is the MQA (Master Quality Authenticated) standard that's quickly growing in use.
Now that we've described how Hi-Res audio files are distinctive, can we actually tell the difference between a Hi-Res file and a so-called ‘low-res' sound?
Do High-Resolution (Hi-Res) Audio Files Make A Difference?
The answer to this question largely depends on the audio setup your listeners – or perhaps you – have.
Using a higher sampling rate doesn't give most people many benefits in sound quality. This is because 44.1 kHz already reproduces the entire sound range that the human ear can perceive. We're then looking at the accuracy of the sound to determine the benefit of a high sample rate.
A higher sample rate reduces audio aliasing – a sampling error when using low sample rates. With 44.1 kHz, a low-pass filter is used to eliminate this. However, a higher sample rate will natively reduce this error without the need for a filter. This will inherently increase the sound quality.
Therefore, a listener may be able to perceive a difference if they have a high-quality Hi-Fi audio setup – like studio-grade headphones or an expensive speaker system.
The dynamic range of a higher bit-depth can really only be enjoyed when using a powerful amplifier that is able to enhance the audio signal so that you can notice the difference.
However, Hi-Res audio isn't as game-changing as companies like Sony are marketing it to be. The reality is that most people won't be able to notice any difference – as most people can't really tell the difference between 320 kbps mp3 and lossless FLACs at CD quality.
There is a clear downside to Hi-Res audio that everyone can notice: file size. As we're increasing the amount of data in each audio file, Hi-Res audio has much larger file sizes than ‘low-res' audio. This takes up more space on a drive and eats up listeners' data allowances and bandwidth.
There is, however, one more key advantage. Hi-Res audio is usually mastered to take advantage of the higher dynamic range, so it is inherently mastered for better sound quality. This works in the same way that HDR video usually leads to better-looking visuals, even in SDR. So, by mastering in Hi-Res, you're creating a better master and, therefore, a higher quality mix.
To learn about digital audio formats in much more detail, check out my article Complete Guide To Digital Audio Formats (MP3, WAV, & More).
Have any thoughts, questions or concerns? I invite you to add them to the comment section below! I'd love to hear your insights and inquiries and will do my best to add to the conversation. Thanks!
This article has been approved in accordance with the My New Microphone Editorial Policy.