What is an Audio Interface and How Do You Choose One?

What is an Audio Interface?

An audio interface is how you hook up your musical instruments and other gear to your computer. From recording basic guitars to tracking professional drum loops, audio interfaces give you the ability to record music using external instruments. Digital Audio Workstations (DAW) give you a lot of options to optimize your sound, but without an audio interface you will never be able to get a good input to utilize those options.

Audio Interfaces come with different types of connections (discussed further in the article) that make recording possible. Your gear transmits analog signals that your audio interface will then convert to digital, enabling you to record your music on the computer and then take that digital sound again convert it back to analog, so you can play the tracks and listen to what you have recorded.

The main components of an audio interface include: DAC (Digital to Analog Converter) this takes the digital audio from your computer/device and converts it back into analog form for playback, Preamps these are what amplify the low level signals, Input/Output channels how you connect instruments and output devices such as Monitors or Headphones. Depending on how fancy your interface is, it can have a bunch of other features such as DSP, ADAT, SPDIF and many more.

In the last two decades Audio interfaces have soared in popularity. PC based recording has become more mainstream and these small, yet powerful, devices have pretty much defined what music sounds like today. If you’re a musician or producer who wants to record and edit music on your computer, then an audio interface is a must-have piece of equipment.

If you’re just starting out, you may be confused why you actually need an Audio Interface. After all, every computer comes with a built in Sound card that is sufficient for music playability. While that is true, a built-in sound card is not designed for music production. Even for a small passion project, you will need to use an audio interface if you want it to sound good.

Different Components of an Audio Interface to Help You Choose the Right One

Inputs and Outputs – What are They and How Many Do You Need?

The Input Output (I/O) configuration is arguably the most important criteria for choosing an Audio Interface. If you’re just looking to have fun at home, record some tracks, plug in a mic or an instrument or two, then you can just go with a two to four channel unit.

You do want to pay attention to the signal type though (Mono vs. Stereo). For example, a dual unit may be 2 x mono OR 1 x stereo. The difference is in the dynamics of the recording. A mono recording is a single channel recording, if you look at your DAW, you’ll see a single track. A stereo differs from a mono because it is two tracks being recorded.

A good example would be, when you’re playing back your recording, mono when played out of two speakers is the same recording being played in the left and the right speaker simultaneously, whereas a stereo recording is two different recordings being played (one from the left and the other from the right speaker).

While stereo is a more advanced form of recording than mono, it isn’t always better. If you’re just recording voice, it may be better to go with mono. Whereas stereo recordings are more wider and have better sound of space characteristic. However, stereo recordings can sometimes have noise cancellation issues.

The inputs are further categorized into instrument/vocal type inputs. For example, for vocals you ideally want something with Phantom power (condenser mics) whereas for plugging in instruments you’re looking at different instrument level hi-Z inputs. If you have multiple mics plugged in, then you’re going to need ADAT or S/PDIF to manage more than one mic preamps at the same time.

If you’re just starting out, then honestly a couple inputs will suffice. It’s hard to make the call initially since your taste and use cases develop with time and that is when you will know what you really need. A rule of thumb with I/O is the more the merrier. You can record an entire live band with an interface that has a more advanced I/O configuration.

Sound Quality – The Obvious Metric!

The sound quality is by far the most important aspect in choosing an audio interface. The reason why a lot of people/artists purchase an audio interface is to improve their audio output quality. An audio interface can dramatically improve sound quality depending on its stats and the components it’s made from.

DAC (Digital to Analog Convertor)

An audio interface contains converters(ADCs and DACs) that transform the state of the audio signal. These converters can also be found in any audio transmitting device but are usually of lesser quality. During the conversion process, audio data will always be lost. However, the quality of these converters dictate how much data will be lost. While converters don’t directly improve your sound quality, they enable your interface to recapture data more accurately, hence you get higher resolution audio.

Dynamic Range

The dynamic range of your audio interface is probably the most significant stat when choosing an audio interface. While the dynamic range isn’t a component, it really affects the quality of your audio.  The dynamic range is essentially a converter stat. Where, a higher dynamic range means that there is more variance between the loudest and softest part of your audio. This really makes your audio stand out and sound much more lively and powerful.

Preamps

A lot of audio interfaces also contain preamps. Preamps allow you to vary the gain on your audio signals. Meaning that you can amplify low signal audio to become audible. The quality of your preamps determine whether your amplified signal will be noise-free when varying the gain. In low quality preamps, your audio will start distorting when you crank the gain knob all the way up. However, high-end preamps produce really clear and granular audio with almost zero noise even with the highest gain settings.

Compatibility and Connection Options – Which One is Best For You?

Thunderbolt

Thunderbolt is the king in terms of connectivity! It is known for low latency and has it’s own chipset. You will find thunderbolt hardware on the more expensive Audio Interfaces. The Thunderbolt 3 (latest version) is what is now available on all of the new Macbooks as well. While it is known for it’s speed, it only makes sense to get one if you actually do have more bandwidth to transfer.

USB

Probably the most common port known to mankind. You have these on all laptops, so the compatibility issue is never going to be there if you go with an Audio Interface that uses USB ports. USB interfaces are the most common ones in the market. You will find constant comparison between USB and TB3 ports, mostly for latency based issues. To be honest, a good USB device, even if it is a USB 2.0 will perform on par with a TB port, or the difference is going to be so minor that it will not really be detectable by human ear.

FireWire

FireWire used to be the Lamborghini of all data ports in the past, however, that is certainly not the case anymore. The final version was the FireWire 800. You’ll often see FireWire being compared with USB, however, USB 3.0 completely destroyed this port.

Advanced Features/Technical Specifications

Sample Rate

During audio processing, there is a lot of audio state conversion involved. Essentially, what we hear is in analog state, while the signal that a computer can process is exclusively in digital state. This is where sample rate comes in. Analog signals contain an infinite number of continuous varying values. So, in order to convert this signal into a digital form, the ADC(Analog-to-digital converter) has to take samples at regular intervals of time to form a digital signal made out of discrete values. In essence, the sample rate is the number of values taken per unit to convert an analog signal into a digital one.

We can hear audio frequencies at 20kHz or below. And according to Shannon-Hartley theorem, the sampling rate/frequency should be at least twice the value of the signal’s maximum frequency. That’s why the standard sampling rate for a CD is 44.1kHz. The sampling rate, however, can be much higher.

For example, some of the most common sample rates in ADCs are 48kHz, 96kHz, 176.4kHz, or even 192kHz in high-end equipment. Having a higher sample rate means that less audio data is lost during the analog to digital conversion. However, in most cases the difference really is insignificant to the human ear, but some producers still prefer going with devices that have a higher sampling rate to prevent audio degradation.

Bit Depth

We just defined the sample rate as the number of samples taken per second at fixed time intervals. Bit depth on the other hand defines how many bits of information each sample contains. Essentially, bit depth measures the resolution of the samples being taken.

To simplify this, you can think of bit-depth as the number of pixels in an image. The higher the number of pixels, the higher resolution of the whole image. So, the more pixels an image contains, the more details it has. This is in a sense analogous to bit depth. Where, a higher bit depth means that more data is captured. This also directly translates to more dynamic range in recordings.

The most common bit depths used for audio recording are 16-bit, 24-bit, and 32-bit depth. As mentioned, the higher the bit depth the higher the dynamic range and the accuracy of the audio. However, in most cases, the difference in bit depth is almost negligible to the human ear. Plus, there are other factors that affect the dynamic range. For instance, the quality of the DAC, ADC and the preamps dramatically affect the dynamic range.

When recording or mixing music, it’s important to have a large dynamic range so that you can capture all the nuances of the performance. A higher bit depth will give you a better signal-to-noise ratio, which means that your recordings will be cleaner and more accurate. Plus you get more headroom to play around.

Latency

Latency refers to the delay between when a sound is produced and when it is heard. This can be due to a number of factors, including the quality of your audio interface, the buffer size, the sample rate. or the speed of the computer processing the audio.

Low latency is crucial for recording and performing, as it allows for a more natural feel and prevents lag. If you are recording audio, you want to hear the playback as close to real-time as possible so that you can make adjustments accordingly. If there is too much latency, it can be difficult to properly monitor your recordings.

While some latency is unavoidable, there are ways to minimize it. One is to choose an audio interface with a high-quality converter. This will help ensure that the signal stays strong as it travels from the source to your speakers or headphones. Additionally, you can choose an interface with low-latency monitoring capabilities. This means that you can hear yourself in real time without any noticeable delay.

Other ways include choosing an audio interface with a low buffer size, using a Direct Sound or ASIO driver, and minimizing the number of plugins being used. Some audio interfaces also come with built-in DSP (Digital Signal Processing) which can further help to reduce latency.

Most modern interfaces have very low latencies, and as long as you’re not trying to do anything too complicated, you shouldn’t have any problems. However, if you are planning on doing more advanced recording or live streaming, then latency becomes a lot more important. In these cases, you’ll need to make sure you choose an interface with very low latency, otherwise you’ll end up with a lot of unwanted lag .

48v Phantom Power

48V power, commonly referred to as phantom power is a feature that allows you to use condenser microphones. Some audio interfaces have phantom power built-in, while others do not. However, if you plan on using a condenser microphone with your audio interface, make sure that it has phantom power. Otherwise, you won’t be able to use it with the interface.

Condenser mics are a type of microphones that are really sensitive and accurate. This makes them perfect for producing clean and professional recordings. However, the outputs on these mics have a really high impedance(the resistance of non-resistor components), as a result, they require a much higher voltage than the supplied 12V. Therefore, certain circuitry is implemented in audio interfaces to step up the supplied 12V to a 48V power. This voltage is usually enough to power most condenser mics.

Most professional audio interfaces will have phantom power, but it’s not always available on cheaper models. If you’re going for a budget-friendly interface that still offers good quality, make sure to check that it has phantom power before making your purchase.

Additionally, keep in mind that some audio interfaces have more than one channel of phantom power, which means you can use more than one condenser microphone at a time.

Drivers

Drivers are what enable your computer to communicate with your audio interface. Essentially, your audio interface acts as a hub for all your I/O. So, to allow the audio data to be transmitted between your PC and interface, you need to install the appropriate drivers. Drivers aren’t physical devices, rather software which you can download from your audio interface’s product page.

Each audio interface has its own driver requirements. These drivers also differ depending on the operating system of your computer. While the majority of interfaces demand that you download drivers, some are class-complaint. Meaning that you don’t have to download any drivers, they’re plug-and-play.

Physical Features

Size, Mobility and Ease of Use

One of the most important aspects in choosing an interface is its size and ease of use. Audio interfaces really are multi-purpose tools. You might be looking to use one for audio playback, music production, streaming, etc. As such, you should pick the most suitable nterface that suits your purposes.

If you’re a traveling artist, you might want something that is light and compact with just enough features. As a music producer, you probably prioritize getting the maximum amount of I/O and features. However, this usually comes at the cost of a bigger and more complex device. Size and usability are features that you should really factor in when picking an interface. In most cases you will have to sacrifice features for a smaller size or vice versa.

If you’re looking for something small and portable then do not go for an interface with a ton of I/O options, and do not get a rackmount interface since those are always larger.

Sturdiness or Build Quality

When you’re buying an audio interface, you want something that will last. There are a lot of cheap audio interfaces in the market that might get the job done. However, a lot of those are poorly built and won’t last long.  In addition to poor material,  some are even poorly soldered or have build defects. That’s why, when you’re choosing an interface, you should take into account its sturdiness and build quality. Always go for something that’s durable and can take a bit of a beating.

How much does an Audio Interface Cost?

While there are hundreds of choices out there when you’re looking at purchasing an audio interface, your actual choices are limited to how much money you are willing to spend.  There are audio interfaces available at a variety of price points. If you’re on a tight budget, you may want to look for an interface that’s less expensive.

You can purchase a really basic interface for a hundred dollars, but if you’re looking for something fancy then the sky is the limit, right? However, keep in mind that cheaper interfaces may not have all the features you’res looking for.

So ask yourself what type of interface do you need? If you’re only going to be using your interface for basic recording, you may not need to spend as much as someone who needs an interface with more advanced features.

You also want to consider what brand of audio interface do you want? There are many different brands of audio interfaces available. Some people prefer one brand over another for various reasons. Do some research to see which brands are most popular and why.

Finally, keep in mind that the cost of an audio interface is just one part of the equation. You’ll also need to factor in the cost of other equipment, such as microphones and cables. When you’re budgeting for your new audio setup, make sure to account for all the necessary components

What Audio Interface do I need? (Analysis Paralysis?)

There are so many different kinds of Audio interfaces out there today, that it ends up confusing the hell out of people. Hundreds of online forums with audio enthusiasts elaborating their experiences in form of mini reviews. There are typical fanboys of a certain brand or a model, and then there are those who are opinionated! To tell you the truth, this is all subjective!

Any audio interface will enable you to record music, however, the devil is in the details. What is it that you are trying to do? How big of a project are you working on? How many inputs do you need? What amount of money are you willing to spend? And more importantly what kind of sound are you chasing? These are some of the questions that will help steer you in the right direction.

We get it, all of this sounds pretty confusing! Well, you don’t have to worry. We’ll go through all of the main selection criteria in detail, so if you’re planning on purchasing an Audio Interface right now or in the future, you’ll be able to make a well informed decision!