What is a DAC?
Chances are you have come across discussion of a DAC if you’ve ever searched for answers online about sound quality and audio devices. It’s not uncommon for customers to reach out with questions on the topic, ranging from ‘what is a DAC’ to anything else you can imagine. There are a plethora of audiophile forums and articles that go into all sorts of advanced detail–in this piece we’ll be covering the basics of a DAC so that you can have a good understanding of what a DAC is and when you’re using one.
What is a DAC in simple terms
DAC is an acronym – it stands for Digital to Analog Converter.
A DAC is what converts digital signals to analog signals. This conversion allows a device, such as headphones or a speaker, to play sounds that were stored digitally.
What’s the difference between analog and digital?
When we want to play audio there are two formats it’s recorded or saved to; analog or digital. The difference between them is that analog is a constantly variable form of information, whereas digital is incremental.
Let’s explain using clocks as an example. An analog clock – a circular clock with hands and a dial – has 60 markers on it to show how many minutes have elapsed but the minute hand still sweeps in-between those minute markers so you can tell approximately how many seconds have passed as well.
Compare that to a digital clock’s minute increments, it only shows you the minute you’re on – it’s fixed. No matter how close you look it’s always going to be 12:08 and until that changes to 12:09 you really won’t know how many seconds have elapsed.
So an analog clock is constantly variable, always changing, there are no fixed increments like a digital clock.
We can relate audio storage to this clock analogy. A record has a single groove that wiggles back and forth and it’s constantly changing – there are no steps or jaggies, you can zoom in on it and it’s still nice and curvy – it’s analog.
A CD on the other hand, stores information like frequency and volume in discrete increments. It’s like a staircase rather than a hill. It approximates a smooth, constantly changing analog signal.
And what reads a digital file’s incremental levels and turns it into a nice smooth analog curve? The DAC.
Why do we need to use a DAC?
Why use a DAC? Why are we complicating things with digital and analog signals and a DAC? There are two main reasons:
You can’t store analog files on a computer
You can’t store analog files on a computer because that’s just not how computers work. Computers are binary machines, they store data in chunks, there’s no way it can store a constantly changing signal – that would require infinite storage as you’d have to capture infinite increments between levels. Think back to that analog clock – you can keep zooming in infinitely between those minute markers to see seconds, milliseconds, and so on.
Speakers are analog devices
The second reason you have to do this complicated transition from digital to analog is that speakers are analog devices. The driver in the speaker is a physical object moving back and forth hundreds and thousands of times a second to reproduce the sound waves that the original instrument or singer was emitting. It’s constantly traveling in and out smoothly, there are no fixed rigid steps.
So quite simply, a DAC takes the intangible binary code in a digital audio file, reads the fixed steps, and smooths it out into a constantly variable curvy signal using math.
And what is the signal made of? Voltage. It turns the digital file into a constantly fluctuating electrical signal that your analog speaker can actually use.
When Am I Using A DAC?
You should always be able determine where the DAC is being utilized in your audio chain just by knowing what inputs you’re using:
- RCA and AUX are analog inputs which means a DAC must have been used somewhere prior in the chain.
- USB, optical, and coaxial are digital inputs which means conversion to an analog signal still needs to occur before the speaker can play.
If I’m using the RCA input on my speaker am I utilizing the built-in DAC?
No, because RCA is an analog input. You need to feed an RCA input a constantly changing electrical signal that can be amplified by the speakers’ amplifier and then fed into the drivers. There is no DAC on the RCA input as the sound going to it is already analog.
If I plug my phone’s headphone out into the speaker’s AUX input I am using the DAC of the phone or the speakers?
If you’re using a digital device, like a phone, it can only store digital music. So if you’re streaming from Spotify, and you’re successfully hearing music on our speakers, it had to have gone through a DAC at some point in the process.
If your phone is connected to our speakers through AUX, an analog input that only accepts voltage, it had to have been converted from digital to analog before it hit the speaker. The conversion had to have happened in the phone, using your phone’s DAC.
Can I use an external USB DAC if your speakers already have a DAC built-in? Can I run both at the same time?
You can use an external DAC with our speakers, but the point of that external DAC is to take digital audio and turn it into analog. It’s outputting a constantly fluctuating voltage which needs to go into an analog input like RCA or AUX. It’s not a digital signal anymore so it cannot go through a second DAC – you can’t run two DACs at the same time.
When I switch between phono and line, am I enabling or disabling the DAC?
Since turntables and records are analog devices, no conversion is needed. That little switch on some of our speakers simply boosts the quiet signal that comes from a turntable so that it can be as loud as modern devices. No DAC is part of the process at all, which is pretty rare in this digital world we live in.
Know when you’re using a DAC
To summarize, audio needs to be converted to analog at some point since the drivers in your speakers need constantly fluctuating voltage to move in and out.
- If you have an audio device connected to the analog input of our speaker, a DAC was used before it hit the speaker.
- If you have an audio device connected to the digital inputs of our speaker, the DAC inside our speaker is being utilized.