A DAC, or digital-to-analogue converter, is an essential part of any modern audio-listening system. But how does it work? And do you really need to shell out a ton of money for a new or upgraded DAC that promises to deliver better sound from your speakers?

Before we answer those questions, we need to clarify what a DAC actually does. In this guide, we’ll discuss how a DAC converts audio from CDs, MP3s, and streaming services into an analogue signal that your speakers can use to produce incredibly detailed sound.

What is a DAC and what does it do?

A DAC converts digital audio signals to analogue audio signals. It’s that simple — but only if you understand the difference between digital and analogue signals in the first place.

When you listen to a live performance, your ears are picking up an analogue signal. This signal is smooth and constantly variable, with no sharp edges that separate one part of the sound from the next. When you listen to a speaker, you’re also hearing an analogue signal — one that’s produced by a constantly fluctuating stream of electricity.

Some physical mediums use analogue signals, too. Vinyl records have a tiny groove that moves back and forth in a wave-like fashion, never fully stopping at one fixed location. A record player picks up the vibrations made when a needle moves through this groove and sends it through an amplifier and into a speaker. No conversion is necessary here, because you’re starting with an analogue signal and ending with an analogue signal.

That’s great if you only listen to vinyl. But most people these days listen to music from laptops and smartphones, which store songs in MP3 files and other digital audio formats. These formats are digital, which means that they store audio information in discrete increments rather than as a continuous signal. These increments are essentially tiny snapshots (or samples) of the original analogue signal captured by the microphones during the recording process.

Digital audio formats help us store audio in a conveniently tidy package, but they emit digital signals that can’t be interpreted into sound by an electrical speaker. The signal must be converted back into an analogue electrical signal that the speaker can use — and this conversion is exactly what a DAC does.

How do DACs work?

We know that a DAC somehow takes a digital signal from a stored audio file and transforms it into a curvy, continuous analogue signal. But how?

DACs work by taking tiny snapshots, or samples, of the digital signal and stitching these snapshots together into an analogue waveform. A DAC might take thousands of samples from a single second of an audio file (the exact number of samples it takes per second is referred to as the sample rate). It then plots these samples on a graph and creates a curved analogue wave that intersects all of the individual sample points.

Ideally, a DAC should follow a consistent timing sequence when it converts a digital signal to an analogue signal. To accomplish this, a typical DAC relies on a master clock that is precisely tuned to the sample rate.

But in some DACs this clock can be more prone to errors. If a clocking error occurs, you may be able to detect a slight degradation in sound quality. This is because the individual samples aren’t being converted at consistent times, and the sound is thus distorted when played back.

This generally isn’t a problem with modern DACs, as many of them decode digital files at a rate higher than the human ear can detect. But it may be something you run into if you’re relying on the built-in DAC in your phone or laptop, which may not be as good at handling clocking errors as a high-quality DAC (such as the built-in DAC of Sonos Port).

When to use a DAC

So, do you actually need to upgrade your sound system with an external DAC? In most cases, your sound system likely has a great DAC already built in to it. This is the case with Sonos Port and our other wireless speakers, all of which come with a high-quality DAC.

But if you’re relying on the DAC built in to your smartphone or laptop, then yes, many external DACs are superior at limiting clocking errors. Whether you’re able to actually detect those clocking errors, in any case, depends on how well you can hear; it’s not a given that you’ll be able to tell the difference.

If you’re streaming music from a digital device into a DAC-less sound system, you might want to experiment with a USB DAC that connects to the USB port of your computer (it can also connect to your phone via a USB adapter).

Can I get better sound by using two DACs instead of one?

No. You only need one DAC to do the job. So, if you stream music from your phone to a Sonos speaker, you’ll only need the speaker’s built-in DAC to convert the digital signal from your phone into an analogue signal the speaker can interpret.

This makes intuitive sense — since a DAC’s job is to convert a digital signal to an analogue signal, it doesn’t make sense to stack two DACs on top of each other. Once the digital signal has been converted to analogue, it isn’t digital anymore. Simply put, an analogue signal can’t be converted to analogue again.

With that said, you can bypass the internal DAC of your phone or laptop by connecting to an external DAC with better components. Your device will send a direct digital signal to the DAC of your choice, which will convert it into an analogue signal and send it through to your speakers or headphones.

How Sonos does DACs differently

Sonos takes care of the DAC question for you.

With its built-in DAC, the Sonos Port seamlessly converts the signal from your favourite streaming service or digital media player into a smooth analogue wave, ensuring that your audio is as crisp and clear as possible.

For a wired setup, you can connect one end of a digital coax cable to the digital coax input on your receiver. The built-in DAC will convert this digital signal before sending it onward to the speaker.

Though a weak DAC can be a limiting factor for your system, your overall sound quality depends on a lot more than just your DAC. Your speakers and other components also matter — a lot! We’ve taken any possible weak links out of the equation with our ready-made speaker sets, which include options with powered all-in-one speakers, subwoofers, and more.