Believe it or not, the DAC or Digital to Analogue Converter plays a pretty vital in our lives on a daily basis. You may not realize it, but if you pulled out your phone to listen to some of your favorite tracks today, silently in the background, a DAC was at work converting your track into a listenable format.
But what exactly is this unsung hero of digital conversion and how does it work? Today we’ll be looking at exactly what a DAC is and the difference it makes.
What Does it Do?
Firstly we’ll take a brief look at the difference between digital and analog formats. Analog formats do not require the use of a DAC as they transmit data in a way which your speakers or headphones can understand and playback natively. Record players are perhaps the most popular and mainstream method of analog audio currently. The key characteristic to analog audio is that it is stored in a physically manifested method. If you run your fingers over a record, you will physically be able to feel the grooves present which represents the audio track.
In the case of a record, while things such as amplifiers to increase the volume and automatic spinning plates spin the disk for you, in theory, you could listen to a record without the aid of a power source at all with the correct equipment.
But what about digital?
Digital recordings, the ones which we’ll be focusing on in this article, however, use a method called “Quantization”. Without going too in-depth as to how this works, the process essentially involves converting the audio being recorded into a series of zeros and ones and storing them electronically, whether that be on a CD or in flash memory.
By doing this, the data then becomes digitized and our digital audio track is created. As you may have guessed, there’ll be no “feeling” an audio track. Anything involving digital data, however, will require a processor in order to decode all these zeros and ones and organize them into something that makes sense.
While many pros and cons exist in both Analogue and Digital formats, this is a debate for another day. It’s widely accepted though that digital audio storage is the most convenient and mass adopted method of listening to our music.
But where does DAC come into in all of this?
As speakers and headphones are very much analog devices, there’s no way of them being able to process this series of zeros and ones. In order to do that, we need a DAC to take those numbers and translate them into something “physical” which can be fed the speaker and played back to us.
As you may have guessed by now, this needs to be done by a powered processing unit. Digital data can only be read with a power source and decoded by a computer.
How Does it Work?
I previously mentioned that a DAC processes the data into something “physical”. Now, when I say this, I’m not necessarily talking about something you can see or feel up front. When audio is pumped through the wiring in your speakers or headphones its done in small electrical impulses.
These electrical impulses vary in length and intensity which makes up the different unique sounds we as humans can hear. The speaker, in a remarkably simple way, takes these signals and reacts which them creating sound.
From Analog to Digital
Now the important job for the DAC is creating something that is consistent and true to the original. There are a few things it needs to do in order to recreate the track truly though.
If we go back to the actual recording of the track and the way it has been digitized for a minute, I want you to visualize something. In real life, all audio travels through the air in waves. Smooth, consistent and predictable waves.
When something is recorded digitally and converted into those zeros and ones, however, the data is captured as multiple tiny increments that stop and start rather than one continuous flow. If we were to visualize it, it looks something like a set of steps.
Because of this, we have something similar to the real thing, but there are numerous gaps where the process waits to record the next data point. Not ideal if we’re looking to recreate the real thing, right?
So when this is finally played back, these gaps will need to be filled in to ensure a smooth and true-to-original playback. This is achieved through a process called “Interpolation”. The DAC analyses the wave and uses the information it knows about the next and previous data point to smooth out the wave and replicate that of a physically produced sound.
Are All DACs Created Equal?
Short answer: No
While every smartphone, tablet and everything in between contains a DAC, their quality varies greatly.
One of the biggest issues in smaller devices is “Jitter”. As the data that needs to be processed travels through the circuitry of your devices, the data becomes degraded. Imagine a game of Chinese whispers, each time the data is transferred there’s a risk that the final result picks up on false information or that information just does not arrive at all. Given that the average smartphone is packed with an array of circuitry, it’s no wonder that this isn’t something they particularly excel at.
Other devices such as car stereos, however, have built-in solutions that perform exceptionally well. The only downside to this is that the data needs to reach that car stereo in digital form. What this means is that, essentially, you’ll have to connect your device via USB rather than a 3.5mm cable. This is because the aux port on your phone is analog and the moment that data leaves the jack, it needs to be in usable form for the speaker. USB, however, is digital and the data being transferred through it remains that way until it reaches the last digital part of the connection that can understand digital data, in this case, the car stereos output port.
In response to these less then spectacular internal DAC solutions, many manufacturers have begun producing external DAC devices which are dedicated devices devoted to producing the best possible conversion process. There is a wide array on the market today specializing in different aspects such as portability etc., but generally, they’re aimed at true audiophiles and often come with a hefty price tag.
While some sites trying to get you to buy one of their DAC products may tell you otherwise, if you’re listening to Spotify or perhaps some MP3s you’ve downloaded, the chances are there is absolutely no need for one of these devices. In fact, adding an external DAC to the equation may even lead you to think the audio quality has degraded as the compression techniques in modern music will be more apparent.
That said, if you are into hi-resolution audio and are using FLAC or other lossless files or perhaps you’re signed up to a lossless streaming service such as Tidal’s Hi-Fi, then certainly you will see the benefit, provided you have the headphones or speakers to reach these ranges too.
DACs are a critical part of modern daily life. These magic little processors work behind the scenes every day to enable us to listen to our digital music.
If you asked the average person, they would probably have no idea that they even existed, which is perhaps a testament to their ubiquity.
While built-in DAC options certainly do the trick, if you are a true audiophile then certainly look at external options. Manufacturers are well aware of their shortcomings in smaller devices and try their best to play to their strengths. Given that most people are happy with compressed audio formats, it wouldn’t be cost or time effective to include anything of higher quality into most mobile devices.