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Sonos is a leading American audio technology company that is best known for pioneering wireless multi-room audio systems, which make it easy for listeners to stream music and other content throughout their homes. The company continues to innovate, creating wireless speakers, home theatre systems, headphones, architectural components, and integrated home audio solutions that revolutionise how people listen and connect to sound.

A speaker amplifier, or ‘amp’ for short, is an electronic device that boosts an audio signal’s power to a level that can be heard through speakers or headphones. Some form of a speaker amp is necessary regardless of whether you’re playing music from a turntable, a laptop, or a CD player. But that doesn’t necessarily mean you’ll need to invest in a standalone amp, as many amps these days are built in to the speakers themselves.

In this guide, we’ll review the basics of speaker amplification and help you decide if you need an amp for your setup.

To explain the job of a speaker amp within the context of a home audio setup, let’s start with an example of what an audio signal can sound like 

If you play a vinyl record before connecting or turning on your speakers, you’ll notice a faint sound of music emanating from the turntable itself. Sometimes referred to as ‘needle talk’, this sound is actually the vibration of your record player’s stylus as it runs along the record’s groove. Without amplification, this vibration can sound high-pitched and as quiet as a whisper. Before you can enjoy it as music, it must be converted into an electrical signal and made louder. Much louder.

A speaker amp is the device responsible for boosting — or 

 — this electrical signal so that it can be heard from your speakers as music. Think of an amp as the muscle of your audio setup, taking a weak signal from your audio device and boosting it to a level that can drive your 

So, the speaker amplifier’s primary job is to increase the volume of your audio. But an amp also has other responsibilities. It helps to regulate the level of power supplied to your speakers so they don’t get pushed beyond their limits and damaged. An amp can even shape your sound in various ways, from reducing distortion to adjusting the audio signal’s tone and frequency to suit your preferences (a process known as equalisation or EQ).

A speaker amplifier works by taking a weak electrical signal from your musical source — like a turntable or CD player — and increasing its 

. Amplitude is a measurement of a sound wave’s strength, with higher amplitude sound waves creating louder sounds and lower amplitude sound waves creating quieter sounds.

Once the audio signal is amplified, the amp sends it to the speakers. The powered signal then creates vibrations in the speaker cone, which generate sound waves that your ears hear as music.

Most amps come with controls that allow you to fine-tune the sound and adjust the gain, which refers to how much the audio signal is boosted before it’s sent to the speakers. More gain means more volume, but too much gain can distort the sound quality and result in a phenomenon called ‘clipping’, whereby the tops and bottoms of the sound wave are chopped off because the amp can’t handle the full breadth of the signal. Not only can this sound unpleasant, but it can also damage your speakers by pushing them beyond their maximum capacity.

Fortunately, most high-quality amplifiers have built-in protections to prevent any damage resulting from excessive gain. These amps may limit the amount of power sent to the speakers to avoid issues like overheating and tearing of the speaker cone.

One point to underline here is that, regardless of its type, an amp relies on electricity to work, so it will need to be either plugged into an electrical socket or powered by a battery.

Amp placed next to a turntable on a shelf

 to listen to music or watch films with your 

. But if you’re looking for the amp in your home audio setup and can’t find it, there may be a good reason.

While an amp is always a necessary component, it isn’t always a 

 component. Most Sonos speakers, for example, include a built-in amp so they’re ready to play right out of the box. These are called 

, or powered speakers, because they actively generate their own power and don’t require an external amp.

Speakers without built-in amplifiers are commonly referred to as passive speakers. These speaker types are often used in 

, where the speakers are discreetly installed into a room’s walls or ceiling. Passive speakers require power from an external amp, like our WiFi-enabled 

 will largely depend on your audio setup and your willingness to pair your speakers with an external amplifier. A 

 with in-ceiling or in-wall speakers will likely require a separate amp for power. But you can also achieve phenomenally realistic surround sound with, for example a pair of Sonos 

 speakers, each of which includes six class-D digital amplifiers to power your sound experience.

If you’re set on including architectural or outdoor speakers in your home audio system, you’ll need a high-quality amplifier that can deliver enough power for multi-room listening. That’s where 

 can help. With 125 watts per channel, it has more than enough power to produce high volumes with clear, undistorted sound. Whether your goal is a 

 or a smart home with seamless control, Amp is all the amp you’ll ever need.

What Is a Speaker Amplifier (And Do You Need One)?

High-resolution audio — or hi-res audio, for short — is a term you come across a lot when comparing different speakers or audio formats. As you’ve likely guessed, it indicates a high level of audio quality. But high relative to 

 The answer is not simply in the eye (or ear) of the beholder.

Let’s start with some points of comparison. High-resolution audio sounds better than MP3-quality audio. It even sounds better than standard CD quality audio, which was once considered sufficient to capture every aspect of sound perceivable to the human ear. We now know that many people can perceive differences in quality beyond what a CD is capable of reproducing, which brings us to a working definition of high-resolution audio.

Put simply, if a digital audio track manages to 

surpass the quality of a standard CD track

, it qualifies as hi-res audio. ‘Quality’ may seem like a subjective term, but we can evaluate the quality of an audio track using two objective measurements — bit depth (expressed in ‘bits’) and sample rate (expressed in kilohertz, or ‘kHz’).

High-resolution audio is generally defined as audio that captures more of the original track’s subtle nuances and details than is possible with standard CD quality. In practical terms, this means a more immersive listening experience, with greater detail and clarity. In technical terms, it means 

 — higher than a standard CD’s quality of 16 bits and 44.1 kHz.

Those may just sound like numbers to you. But it’s important to understand bit depth and sample rate if you’re interested in enjoying the best possible listening experience.

Bit depth and sample rate: The key components of audio quality

When we talk about audio quality, we’re really talking about how fully and accurately an audio track captures the live sound of a recording. The better the quality, the more you feel like you’re actually in the room listening to a song performed live.

, sound engineers generally want to capture as much dynamic range and frequency response as possible. 

 is the difference between the quietest and loudest sound a recording can produce. 

 measures how well an audio track can produce frequencies from the lowest bass to the highest treble.

Each of these qualities corresponds to a specific measurement: bit depth and sample rate, respectively.

 describes how many tiny pieces of information (i.e. ‘bits’) make up a single snapshot of a soundwave. The higher the bit depth, the more dynamic range the sound has — in other words, the more you can hear the loudest and quietest sounds.

 describes how many snapshots (i.e. ‘samples’) are taken from the original soundwave. The higher the sample rate, the more the track captures the details of the original recording. Higher sample rates also capture and reproduce higher frequencies of sound.

As noted above, hi-res audio files typically feature a 24-bit bit depth and a sample rate of 48 kHz or higher. Both measurements are significantly higher than standard CD quality, which features a 16-bit bit depth and a sample rate of 44.1 kHz.

The below graphic visualises how a 24-bit recording actually captures a wider dynamic range of sounds. You might compare it to using a bigger net when fishing to catch more fish. We’ll get to that in a moment.

Depiction of how 16-bit captures the full range of loudness, while 24-bit captures more than the full range.

What audio file types support hi-res audio?

If hi-res audio is so great, why haven’t we been listening to it forever? 

The answer comes down to technology. More specifically, it comes down to what different audio file types can support — and how big they must be to fit all that audio data.

One of the major differences between audio file types relates to a process called compression. This process takes the original audio waveform of a recording and shrinks it down to a smaller size that’s easier to transfer and store.

Compression can be split into two general types:

 loses some of the data contained in the original audio recording, which may result in a perceivable loss of audio quality.

 retains all of the audio information from the original recording, while still managing to shrink the file size. This is the type of compression associated with hi-res audio.

Some audio file types are uncompressed, and these also retain every aspect of the original recording. The downside is that these file sizes can be huge! So, historically, there’s been a real trade-off between audio quality and storage/convenience. This is beginning to change with the evolution of new file formats that support lossless compression.

To better visualise this, let’s trace the path of how a song recorded in hi-res (24-bit, 48 kHz) makes its way to the listener in the form of an audio file:

Illustration depicting the evolution of a song, from the studio to mastering (24-bit and 16-bit) and compression (lossy and lossless), through streaming.

As you can see, the original recording is typically split into two versions for distribution: an uncompressed raw audio format, and a standard CD format. Data from the uncompressed format can then be used to create lossless file formats like FLAC and ALAC, as well as lossy formats like MP3 and AAC.

Another thing you may have noticed from the above diagram is that both hi-res and CD quality are labelled ‘lossless’. Audio encoded in the CD format is indeed considered lossless because it represents a precise and accurate snapshot of the analogue waveform. Though it may not have the same dynamic range or frequency response of a live performance, a CD doesn’t compress the data in a way that distorts or loses information from the original recording.

, the salient point is that hi-res audio isn’t simply about whether data is lost in compression. It refers specifically to audio that offers higher bitrates and sampling rates than what standard CD quality can achieve. So, a lossless audio track 

The short answer is yes. But not everyone can really tell the difference.

Remember, standard CD quality (16-bit, 44.1 kHz) was once thought to include the full range of frequencies humans can hear. It’s since been shown that some people can actually hear frequencies beyond what CD quality is capable of reproducing. For these people, hi-res audio will almost certainly sound better. But for people whose hearing is damaged or not as good as it once was, it may sound no different from a CD or even an MP3.

If you’re wondering whether you can hear the difference, 

 is a good starting place. For the most accurate results, be sure to listen to it through a pair of quality headphones like 

, or through a system that’s capable of 

More streaming services are beginning to offer lossless or hi-res audio options. Amazon Music, for example, now has many songs available in Ultra High Definition, which they define as “better than CD quality audio (up to 24 bits, 192 kHz).” Apple Music’s ALAC file format is also capable of delivering up to 24-bit/192 kHz hi-res audio, though you’ll have to switch it on in your settings.

A true hi-res audio experience requires not just a particular streaming service or file type, but also equipment that’s capable of accurately reproducing the depth and detail of original recordings.

You can actually stream lossless audio over Bluetooth with 

 headphones — and it’s sure to sound incredible. But for the most accurate hi-res playback experience, you’ll need to connect to a WiFi-enabled speaker, or use Sonos Ace’s included 3.5 mm cable to plug your headphones into an audio source.

It’s not just music that benefits from hi-res audio. A Sonos 

 brings hi-res sound quality to your favourite films and TV shows. A 

 such as Arc Ultra not only supports hi-res audio, but beams sound around the entire room for a more immersive experience.

As the capabilities of streaming and file types continue to expand, Sonos is keeping pace with products capable of doing justice to hi-res audio. You can see which streaming services support hi-res playback (such as Apple Music and Amazon Music) in our support article 

 feature several premium options capable of hi-res playback, including 

 offer a first-class high-res audio experience, thanks in part to 

 and their ability to create an immersive, multi-dimensional soundstages that redefine the possibilities of 

. And our premium over-ear Sonos Ace headphones plug in with a 3.5 mm for a hi-res experience that’s all your own. (Sonos Ace can also achieve lossless quality via Bluetooth or a USB-C connection.)

If you’re interested in upgrading your home audio setup to hi-res, get in touch with a Sonos expert by 

Couple lounging on a sofa with a pair of white Era 300 speakers behind them

The Beginner’s Guide to High-Resolution (Hi-Res) Audio

Though some listeners prefer their shelves of vinyl and stacks of CDs, most music libraries now exist in digital file formats that are more convenient to store and easier to access on the go. But it’s not particularly helpful to simply describe an audio file format as “digital” because that can mean different things — and different levels of sound quality. In fact, audio files come in multiple formats, and not all of these formats are made equal.

One of the major differences between audio file formats relates to a process called 

. As its name implies, compression makes file sizes smaller. This can be useful for saving storage space on a hard drive, but it can also have consequences for the quality of the original audio recording.

The compression process essentially reduces the amount of data contained in an audio waveform, and this loss of data may result in noticeable loss of quality to the listener. Some audio file formats that undergo this 

 type of compression include MP3, AAC, and Ogg/Vorbis.

However the compression process doesn’t 

 diminish audio quality. Some newer compression technologies manage to shrink the file size while retaining all of the audio information from the original recording; audio files that undergo this type of compression are known as 

Finally, there are audio files that undergo no compression. These 

 audio files are generally much larger in size, but they avoid the audio quality issues that plague some compressed formats.

To summarise, digital audio files can be 

. Let’s dive deeper into each type and explore some common examples.

Lossy audio files are compressed in such a way that some of the original recording’s fidelity is lost. You may find it strange that 

 would prefer a lossy audio file to one that retains all of the richness and complexity of an uncompressed file. However, lossy files tend to take up much less bandwidth and storage space, which makes them a good compromise for music-streaming services.

Before you think “lossy” automatically means “bad quality,” consider whether your ears will even notice the difference. Many people find it difficult to detect any difference between CD quality (16 bits/44.1 kHz) and higher bitrate standards, which some lossless file formats technically achieve. If it makes no difference to your ears, it makes sense to opt for a smaller file size when possible.

On that note, let’s look at four lossy audio file types you may come across.

The MP3 audio file format became immensely popular in the early 2000s. At the time, it was among the most efficient ways to get an audio track from a CD and store it on a digital hard drive or on a “burned” CD. The MP3 file format is much smaller than that of an uncompressed CD audio track.

MP3s were revolutionary for their time and led to a huge leap forward in portable listening, as they were the basis for early digital audio players. You may even still have some MP3s stored on your hard drive, but the format is lossy and some people may be able to pick out the difference between an MP3 and a CD-quality track.

AAC stands for Advanced Audio Coding, which is another lossy coding standard used in audio track compression. AAC quality doesn’t rise to the level of 

 but it is a step up from the MP3, delivering better quality at a comparable file size.

Though perhaps not quite as ubiquitous as the MP3, the AAC format is everywhere and you’ve probably encountered it yourself. It was the preferred format of the iTunes music store and continues to be available on AAC-compatible devices.

OGG is a versatile and open-source multimedia compression technology. You may have heard of Ogg/Vorbis, which is an OGG format typically used for audio compression. Spotify frequently uses this format for its streams.

Though lossy, OGG audio files retain quite good sound quality. Their size and quality are both advantages over other lossy compression formats, and they are widely used for streaming audio over the internet.

WMA is short for Windows Media Audio — a hint that this is a proprietary format developed by Microsoft. Though it achieves slightly better quality than MP3, the lossy WMA format is not widely compatible with non-Microsoft devices and thus has limited utility.

Person seated in a chair listening to a white Era 300 placed on a console

 are those that are compressed in such a way that the quality of the original recording essentially stays intact. In other words, no discernible aspect of the audio is lost in the process of compression.

Just be aware that “lossless” does not mean uncompressed. A lossless track is still compressed, though it uses a data algorithm to retain all of the original recording’s quality. Lossless quality generally equates to about 16 bits/44.1 kHz or higher, which means it sounds at least as good as a CD.

Below are some of the most common lossless file types.

FLAC stands for Free Lossless Audio Codec. A “codec” is basically a process that compresses and decompresses digital files, so the name here basically says it all: This was developed as a free way to achieve lossless compression.

Many audiophiles consider FLAC the gold standard of digital audio formats, as it achieves a much smaller size than a raw uncompressed audio file without sacrificing any discernible audio quality.

ALAC stands for Apple Lossless Audio Codec. It was developed by Apple as a lossless successor to AAC. The company currently offers its entire Apple Music catalogue in ALAC resolutions ranging from CD quality to higher.

There is indeed a lossless alternative to the lossy Windows Media Audio format mentioned above. It isn’t as common as FLAC and Apple’s ALAC, and it doesn’t stand out in terms of compression efficiency or audio quality. With that said, this WMA format does offer a lossless audio experience to (primarily) Microsoft users.

Person outdoors listening to Soft White Sonos Ace headphones

As the name suggests, uncompressed audio files do not undergo any type of compression. This means that there is no data lost in the process of compression, and every aspect of the original recording is preserved.

Many audiophiles hold uncompressed file types up as the holy grail of digital audio, but these file types come with a few of their own disadvantages. For one, they tend to be quite large; if you store a ton of uncompressed files locally, you’ll likely need additional hard drive space. Their cumbersome size also means it may be difficult to find truly uncompressed files on many streaming services.

Let’s check out three of the most common uncompressed audio formats.

WAV (Waveform Audio File Format) is a hi-res audio format used for encoding CD audio data. Though WAV files can technically store compressed data, they are typically used for uncompressed audio.

WAV files are known for their excellent sound quality, but they’re also notorious for their very large file sizes.

AIFF, or Audio Interchange File Format, is similar to WAV in many ways. (In fact, it was developed by Apple around the same time Microsoft and IBM were developing the WAV format.)

AIFF audio files are comparable to WAV files, and both are generally compatible with Microsoft and Apple systems. However, AIFF files are rare and suffer from large file sizes, so you probably won’t see them much.

The DSD (Direct Stream Digital) format is another one that’s popular among audiophiles. It aims to capture the original analogue waveform in a way that replicates what you might hear coming out of a high-quality record player. Though beloved among a small subset of listeners, DSD hasn’t caught on with the mainstream and uncompressed DSD files are simply too large to make sense for internet-dependent streaming applications.

At the end of the day, the audio file type you use is only as good as the equipment you play it on. If you don’t plan to invest in a HiFi sound system with quality components, it might not matter whether you use an MP3, AAC, or lossless audio file format.

 isn’t as unattainable as you may think. With a premium speaker like 

 or the spatial audio capabilities of a soundbar like 

, you’ll be more likely to discern the differences between lossy and lossless audio quality.

From there, the file format you choose depends mostly on how you listen to music. If you mostly stream music but want the best quality possible, look for services that feature FLAC and ALAC encoding. If storage space isn’t an issue and you play mostly files from your CD library, WAV could make more sense.

Of course, it helps to be honest with yourself about how much quality really matters. Some people are just fine with lossy formats, and sometimes the convenience of smaller file sizes outweighs any difference in audio quality.

Experience multiple audio formats with Sonos

At this point, you may be wondering what audio formats Sonos supports. Our 

 include many of the formats mentioned in this guide. This includes high-quality lossless and uncompressed audio encoded using FLAC and ALAC, with a maximum bit depth ranging from CD quality to higher.

White Five next to a walnut turntable placed on a console

Beginner's Guide to Audio File Types (And Which to Use)

Perhaps you’ve noticed a recent uptick in music streaming services advertising “lossless audio.” As technology improves, more of these services have been able to improve their song libraries by supporting higher-resolution formats. That’s good news for the millions of music lovers who have adopted streaming as their go-to means of listening to music. However, to take full advantage of this shift, it helps to know what lossless audio actually is and whether your preferred streaming service actually supports it.

Lossless audio can be a confusing term, especially since so many streaming services are now beginning to offer tiers or packages that distinguish between “lossy” and “lossless” file formats. The idea is that lossless audio means higher quality, and this is generally true — though it helps to understand the 

 before you rush to upgrade your audio setup.

Let’s define lossless audio and walk through what you need to listen to it at home.

The term “lossless audio” describes compressed 

 that retain all of the audio information from the original recording. This is in contrast to “lossy audio,” which describes compressed file formats that delete some of the original audio information.

It’s important to note that both lossless and lossy audio files go through a process called compression, which involves shrinking the size of the file so that it takes up less storage space. Compression certainly has its benefits — it makes files easier to store locally and requires less internet bandwidth for uninterrupted streaming. But the compression process can result in the loss of some audio data, which some people may be able to detect as inferior quality.

What’s lost in a “lossy” audio file?

To understand what’s lost in a “lossy” file, it helps to know how sample rate and bit depth work. Together, these two measurements tell us something about a digital audio file’s sound quality.

 Digital audio files take a certain number of snapshots of a recording’s original soundwave, then stitch these together to form a reproduction of the original recording. The more snapshots taken, the higher the sample rate — and the higher the sample rate, the higher the quality.

It also helps if each of these snapshots is capturing the entire soundwave, or just a portion of it. Digital recordings that capture more of the range between loud and quiet are said to have a higher 

Combine a high-enough sample rate with a high-enough bit depth, and you get a compressed digital reproduction that’s basically indistinguishable from the original recording. In other words, you get “lossless audio.” But if the compression process favours a lower sample rate and bit depth in favour of a smaller file size, it may result in a “lossy” audio file.

Person doing yoga in front of a white Beam placed under a tv

Lossless audio is already available on a number of popular streaming services. Apple Music, for example, touts a proprietary lossless audio compression technology called 

. Amazon Music subscribers can also find lossless audio at two tiers of quality: 

High Definition and Ultra High Definition

Both Apple Music and Amazon Music define “lossless audio” as starting at CD quality (or 16-bit). You may not think of CDs as the most cutting-edge technology, but standard CD quality audio was originally determined to be high enough that the human ear could not detect a difference between CD quality and the original recording. 

 show that some people may be able to hear beyond that with training, but if you’re looking for the shortest path to lossless audio, consider dusting off your old CD collection.

Is lossless audio better than regular audio?

The short answer is yes. Lossless audio offers a better and richer sound experience than lossy audio alternatives, which have become the “regular audio” standard thanks to the rise of streaming services.

But for the best listening experience, nothing beats a quality speaker. The difference between an Apple ALAC file and an Amazon Ultra High Definition file is relatively small, but your cell phone’s built-in speaker won’t do either of them justice. To really benefit from lossless audio technology, you’ll need equipment that can handle it.

What do I need to listen to lossless audio?

Lossless audio is much more attainable than it used to be, and a quality speaker or headphones should be all you need. Since lossless audio covers a wider range of frequencies than lossy audio, your speakers should be able to handle frequencies within the full range of human hearing (generally 20 Hz to 20 kHz).

You can even listen to lossless audio wirelessly with Sonos products. Our 

Yes, though this hasn’t always been the case. It’s exceedingly difficult to transmit audio data over Bluetooth without at least a bit of compression, so most Bluetooth speakers and earbuds don’t support lossless audio. Sonos Ace is among a relatively small class of headphones that can achieve lossless audio with a Bluetooth connection. For other headphones and speakers like 

, Bluetooth can still deliver impressively clear sound, though you’ll want to connect via WiFi for the best audio experience.

Person lounging outdoors while listening to Soft White Sonos Ace headphones

You may have heard of other terms used to describe high-quality audio, but how do terms like “HiFi” and “spatial audio” relate to lossless? Let’s take a look.

Because the term “lossless” relates specifically to digital file compression, lossless audio typically describes audio formats that don’t lose any of the original signal in the process of compression. You’d describe an audio coding format such as Apple Lossless Audio Codec (ALAC) as “lossless,” but you wouldn’t use the term to describe, say, a set of premium speakers.

, or HiFi for short, usually describes a full system or setup that’s capable of reproducing audio from the original recording with a high degree of exactness. So, a HiFi setup would include speakers, an 

What Is a Speaker Amplifier (And Do You Need One)?

The Beginner’s Guide to High-Resolution (Hi-Res) Audio

Beginner's Guide to Audio File Types (And Which to Use)

What Is Lossless Audio — And How To Stream It at Home

What Are Height Channels for Speakers and Home Cinema?

How to Hear Dialogue Better When Watching TV Shows and Films

The Beginner’s Guide to Cleaning Headphones

What Is the Bluetooth Range for Speakers and Headphones?

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What Is a Speaker Amplifier (And Do You Need One)?

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Beginner's Guide to Audio File Types (And Which to Use)

What Is Lossless Audio — And How To Stream It at Home

What Are Height Channels for Speakers and Home Cinema?

How to Hear Dialogue Better When Watching TV Shows and Films

The Beginner’s Guide to Cleaning Headphones

What Is the Bluetooth Range for Speakers and Headphones?

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The Beginner’s Guide to High-Resolution (Hi-Res) Audio