High-fidelity audio — or HiFi, for short — is audio that’s reproduced from the original recording with as high a degree of exactness as possible. Short of staging a live show or concert in your living room, a HiFi audio setup should deliver the best sonic quality you can experience at home.

But the term ‘HiFi’ is subjective. It depends as much on personal taste as it does on technical factors. Some might consider the quality of a standard CD to be HiFi, as it hovers near the crispest sound the human ear can perceive. Others thirst for even purer levels of playback, unwilling to forgo the subtle pleasure of picking out a single voice from a choir, or hearing a finger gently settle on a guitar string.

In this guide, we’ll define HiFi audio in more depth, focusing on everything from sound waves to the components involved in a typical home setup. Just as important, we’ll help you define what HiFi means to you. Because what’s the point of HiFi audio if your ears don’t enjoy it?

What is HiFi audio?

HiFi audio is audio that reproduces the sound of an original recording with minimal levels of distortion and a full, accurate range of audible frequencies. If the human ear is unable to discern any difference between an in-person performance and an audio reproduction of that performance, the latter would generally qualify as HiFi audio.

You might assume that the evolution of audio technology in the last century has been one long, uninterrupted march toward HiFi perfection — but you’d be wrong.

A brief history of HiFi

The term ‘HiFi’ was introduced in the 1950s to describe newer at-home audio systems that often involved multiple components. Such setups achieved levels of sonic accuracy that far surpassed the phonographs and AM radio frequencies of yore.

The development of stereophonic equipment, which brings a greater sense of width and spaciousness to recorded sounds, marked an especially important breakthrough in HiFi audio. Another milestone came in the 1980s with the explosion of CDs, a new digital format that reduced noise without compromising much in terms of quality.

But audio quality actually got worse in the 2000s with the advent of streaming, which compresses audio files so that they take up less storage space. This compression often comes at the expense of fidelity. Newer streaming formats have shown better results, but before we get too far ahead of ourselves in talking specs, let’s establish what we’re actually hearing when we listen to HiFi audio in the first place.

Five key elements of HiFi audio

If you were to say that HiFi audio is audio that ‘sounds good’, well, you’d technically be right. But what elements of a recording contribute to its sounding good?

There are a lot of nooks and crannies we could dive into, but here are five major factors to pay attention to when evaluating the fidelity of a digital audio recording:

1. Minimal noise and distortion.
   
   The greater the number of bits in a digital audio recording, the greater the dynamic range. This means less ‘white noise’ during quiet moments, and less distortion of sounds during loud moments.
   
2. Width and spaciousness.
   
   Sound is a vibration that propagates across space. The illusion of this space can be created by stereo equipment that makes the sound from a set of speakers feel more encompassing, and less like it’s coming from a single direction.
   
3. Instrument separation.
   
   The space between sounds in a recording matters, too. HiFi audio should have good separation between instruments and vocalists, so that you can clearly hear the unique characteristics (including the physical space) of each.
   
4. Tonal balance.
   
   The balance of bass, treble, and mid-range in a mix is essential. Too much bass can make a track sound muddy and underwater, too much treble can make it sound tinny and harsh. Most audiophiles prefer a more neutral or natural tonality, with a delicate balance of tonal emphasis.
   
5. Personal taste.
   
   How does it sound to you? This is arguably more important than anything else, and may lead you to a definition of HiFi that differs from the rest.

Now that we’ve reviewed the basic elements of HiFi audio, let’s discuss how two important measurements — sample rate and bit depth — can help you achieve higher fidelity in digital audio formats.

Understanding sample rate and bit depth

Most people these days listen to audio on digital formats, such as streaming services. These formats can be incorporated into a HiFi audio system with help from a digital-to-analogue converter, or DAC.

Beyond converting digital audio into an analogue waveform, a DAC’s job is essentially to fine-tune the tonality and overall sound quality of the digital audio source recording.

It does this by taking tiny snapshots, or samples, of the original soundwave and stitching these snapshots together into an analogue waveform. This follows the same principle as a film camera, which takes tiny snapshots of a live image and stitches them together to make a film.

The sample rate describes the number of snapshots taken of the original soundwave. The higher the sample rate, the closer the reproduction resembles the original. A CD’s sample rate of 44.1 kHz is standard for recorded music, and means that 44,100 samples are taken per second.

If the sample rate represents how many snapshots are taken of a soundwave, then bit depth describes how much each of those snapshots can capture. Greater bit depths mean a wider dynamic range; in other words, a wider difference between the loudest sound you can play back without distortion and the quietest sound you can record before losing resolution.

CDs have a bit depth of 16 bits per sample, which can record over 65,500 amplitude values. This figure isn’t random. The standard sampling frequency of CDs was chosen because it was thought that 16 bits covers the full range of quiet-to-loud sounds that humans can hear. A 2016 study by Joshua Reiss at Queen Mary University of London challenged this notion, suggesting that some people can detect the difference between CDs and high-resolution audio tracks that can achieve up to 24 or 32 bits per sample.

HiFi audio combines a high sample rate with a high bit depth, resulting in a ‘lossless’ and accurate reproduction of the original recording. Whether you can actually hear the difference may help determine which audio quality meets your personal standards.

How to bring HiFi audio into your home

If you’re interested in building a HiFi audio setup of your own, there are a few ways to go about it depending on your budget and desire for customisation.

Many audiophiles prefer to build modular systems that combine a number of different pieces (CD player or turntable, pre-amplifier, DAC, power amplifier, speakers, subwoofer, etc.) from different manufacturers. Alternatively, you could opt for an integrated system that combines several of these components into a single unit.

Audio source

First, you’ll need a CD player, turntable, or streaming platform that delivers your audio. Be aware that certain streaming platforms (like Spotify) don’t have a HiFi audio option, though others (like Apple Music and Tidal) do offer lossless, hi-res audio at certain subscription tiers.

DAC

As noted above, a DAC converts digital audio into analogue. Many HiFi products, such as Sonos Port, have a DAC built-in. This DAC ensures that any streamed audio is converted and reproduced to sound as clear as possible.

Amplifier

An amplifier enhances and increases the audio signal that comes out of your DAC. It boosts the signal enough to power speakers without distorting its quality.

Speakers

Speakers are what sound comes out of. Most HiFi systems have at least two loudspeakers and are intended to be listened to in stereo.

Some individual speakers allow for a stereo experience by configuring multiple loudspeakers within the same enclosure; Sonos Five, for example, houses three high-excursion woofers (low and mid-range frequencies) with three tweeters (high frequencies). And you can pair two Sonos Five speakers for an even more expansive experience.

Room acoustics

The unique acoustics of the room matters, too. It’s amazing what you can achieve just by adding a few sound-absorbing curtains or bookshelves. And if you’re using a Sonos system, Trueplay™ tuning technology analyses every contour of your space to optimise the speaker’s EQ.

You can always add more to a HiFi system (and many people spend their whole lives doing just that). But these essential components should be enough to get you started.

Pros of HiFi audio

Better audio quality.

Some people don’t know what they’re missing until they’ve heard a HiFi system in action. If you’re used to listening through a tiny laptop speaker or even high-quality Bluetooth headphones, you may be amazed by the depth and detail of the sound you’ll hear on a true HiFi system.

It recreates the artist’s intent.

Films are created for big screens and loud speakers. No musician or composer envisions their masterpiece playing through a trebly cassette player. HiFi audio lets you hear these works the way they were intended to be heard.

A deeper listening experience.

HiFi audio can enhance the emotional experience of hearing a piece of music. In some cases, it’s even like hearing it for the first time.

Cons of HiFi audio

You need special equipment.

Not any old headphones, speakers, or streaming service is capable of producing a HiFi audio experience. You will need to invest in some equipment. And skimping on just one component — speakers, an amp, etc. — can ruin the effect of the stuff you do invest in. With that said, HiFi is becoming more and more accessible, and Sonos even offers ready-made sets at different price points to get you started.

Not commonly available on streaming services.

The most popular streaming service, Spotify, still doesn’t offer hi-res audio tracks. Others do, but their hi-res libraries may be limited. This situation is improving, but it explains why so many audiophiles haven’t thrown away their vinyl and CDs.

Larger file sizes.

We’ll get to this in the next section, but since most HiFi audio formats are uncompressed, they tend to take up a lot of space on a hard drive. If you’re serious about streaming HiFi audio, you may want to think about upgrading your disk space.

HiFi file types

Not every file format is capable of reproducing HiFi audio. MP3s, for example, can only achieve anywhere from 96 to 320 kilobits per second (kbps) — a steep drop-off from standard CDs. Here are some formats that can do the job:

Waveform Audio File Format (WAV):

WAV is an uncompressed format that uses the same coding format as CDs. Because it’s uncompressed, file sizes can be quite large.

Audio Interchange File Format (AIFF):

WAV was originally developed by Microsoft, and Apple’s answer was the uncompressed AIFF format. Compressed, lossy variants of AIFF also exist. These take up less space at the expense of quality.

FLAC (Free Lossless Audio Compression):

FLAC is another lossless format that is widely compatible with different systems. Some audiophiles consider it something of a gold standard for combining lossless compression with smaller file sizes than competing formats.

ALAC (Apple Lossless Audio Codec):

Another proprietary format from Apple, ALAC has similar sound quality to FLAC but may be less compatible with non-Apple ecosystems.

Master Quality Authenticated (MQA):

This proprietary format is used primarily for Tidal tracks. Though technically lossy, it may achieve sound quality indistinguishable from other HiFi file types with significantly smaller file sizes.

Is HiFi worth it?

Whether HiFi is worth it to you depends on your answers to a few questions.

Can you actually detect the difference between an uncompressed file format and an MP3? Not everyone can, and it’s not something to feel bad about. Many adults suffer from minor hearing loss that hinders their ability to detect compression.

Do you care? Even some people who can hear the difference between compressed and uncompressed files don’t really mind the former. Others can hardly listen to MP3s after experiencing true lossless quality, deriding the experience as something akin to having mud in your ears.

Do you have the budget to upgrade? HiFi sound doesn’t come free, and you can certainly pour hundreds or thousands of pounds into different components without achieving a sound you think is worthy of your ears. But there are more affordable ways to achieve a perfectly respectable HiFi sound, and it need not break the bank.

Sonos is a great pathway to a HiFi lifestyle. Our popular HiFi set features two Sonos Five speakers that provide a premium multi-room sound experience with detailed left and right channel separation. It may well be all you’ll ever need.