Why Do You Need An Audio Interface? – Complete Guide

need an audio interface

Audio interfaces have become an essential aspect of recording and producing music, and many musicians who work mostly at a computer rely heavily on them. But what are they? And why do we need them? We will get to know more about them in this article.

Audio interfaces allow you to connect all your microphones, instruments, and speakers to your computer to record sound easily. Monitoring the sound is also essential to hear what you are recording. An audio interface allows you to have all these options in one device.

What is an audio interface?

There are many ways to call them. Even if you don’t know it, you have already worked with one. For example, computers and phones have a built-in sound card, which allows you to play music or speak into the microphone in a video conference or video recording. So a sound card, or sound interface, is the same thing as an audio interface; it’s just different ways of calling them. 

We will explain what it is and define its function. The computer is not able to understand the sound. It is necessary to translate it into a language that the computer can understand to work.

The audio interface is the hardware that allows the physical sound produced by an instrument or microphone (also known as an analog signal) to be translated into a digital signal (the one that our computer recognizes). We could say that it is a translator between the outside world and our computer in a few words.

It should be noted that this “translation” is in two ways: input and output. By input, we mean the external signal (microphone) that enters the interface and will be recorded in our computer. Instead, the output is the reverse process, converting a digital signal to an analog signal. We do this when we want to play the recorded information on speakers or headphones from our computer.

As you can see, these two “translation” channels are automatically recording and playback. And they are very common.

Why do I need an audio interface?

We have talked about cell phones and computers having their built-in card or interface, so the question is: why do you need to buy an external one for professional recording? 

The answer is simple. A computer sound card is very simple and limited. It will not be enough to obtain the musical quality we want in a professional audio recording. It is one thing to modify the sound of a headset microphone for a conference or a small video and quite another to capture the harmonic richness of a voice or musical instrument. 

Think of it like this: how many times have you listened to a voice memo, let’s say from what application, and realized that the sound is very poor, barely understandable? Would you like to listen to a recorded song with that quality? Of course not, right? An audio interface has components specialized in audio processing, essential when making music. 

Beyond the recording studio

An interface is not only used for recording; it can also be recorded in live performances. Many bands used previously recorded sounds (known as sequences) to play the sound of the instruments. It is also very common to use digital or virtual instruments triggered by a computer. Therefore they will need an interface to “translate” these sounds and reproduce them live.

How do I know which to choose?

Well, the answer is according to your needs. Below, we will break down the main elements you must consider when buying an audio interface. There are a lot of myths and information out there that can be very damaging, so I’ll try to keep it simple.

1. Inputs and outputs

need an audio interface input ouput

As in the previous paragraph, it all depends on your needs. Considering an interface for its inputs and outputs is essential. For this, you have to know what kind of recordings you are going to make; basically, there are two ways to do it:

Recording by track: We would capture each instrument separately, using the same input channel of the interface. In our computer, the layers would be combined to form a piece of music.

Simultaneous recording: You’ll be capturing all instruments at once, each on a different input channel.

Let’s understand the technical difference between these two cases: In the first case, we can use a smaller interface (with fewer input channels) because we will be recording individually. Each signal may use the same inputs.

In the second case, we will need as many inputs as signals (instruments).

Let’s say you want to record demos of your project with acoustic guitar and vocals. Well, in that case, you don’t need much. You can do this with a smaller interface as you can record the guitar first and then the voice in one channel.

So why record simultaneously?

Well, some instruments demand it. A simple example is a drum set. We cannot record drum by drum as the naturalness of the instrument will be lost. We need one channel for each microphone we use, one for the kick drum, one for the snare, one for each tom, etc.

In general, most recordings today are track by track. You’ll want to do it this way if you produce at home, as an audio interface with more channels will cost more. Analyze your music needs and make a decision based on them.

Types of inputs

There are different types of inputs with different functions. It is essential to understand this because having an interface with the required number of inputs but the wrong type will result in a complete failure. But don’t worry, there are usually two input types, and most interfaces have both.

need an audio interface line input

Line input: This input is where we will connect the instruments that deliver line-level tags. If you do not know what it is about, you can read the article about signal levels. Such instruments are guitar, bass, or synthesizer.

need an audio interface mic input

Microphone input: The name makes it clear that the microphones will be connected. Remember that condenser-type microphones need a voltage of 48v to work. This voltage is known as Phantom Power. Most of the current interfaces must bring the option to activate said power source. Still, it is always advisable to make sure to avoid disappointment.

need an audio interface hybrid input

Combo Input: Today, many interfaces have combo inputs, accepting both line and mic inputs.

Types of outputs

Remember that the audio interface does two things: it converts the analog signal into digital information and then converts the digital information into sound. Outputs are the paths through which an interface can send digital information to speakers, headphones, or other devices.

Audio interfaces usually provide few outputs with a simple configuration. The most common design is a stereo output for your main monitor and an auxiliary output for the headphones. More expensive interfaces have additional outputs.

As I mentioned earlier, we can perform live with the audio interface. This is where outputs are necessary. The more outputs in an interface, the more we can send different signals to different devices.

The main advantage of having multiple outputs on an audio interface is that it allows you to listen to different mixes at the same time. For example, suppose you’re recording a band with more than one member and instruments. In that case, you may want to listen to each instrument separately. This allows you to balance each musician’s level without bouncing between different tracks in your DAW.

2. Preamps

When you record using a microphone, many factors can affect the quality of the recording. One of these is background noise. This could be anything from traffic, machinery, or environment to even people talking in another room or phone. A good preamp will filter out this background noise so that your computer is recording only your voice.

Another essential function of a preamp is gaining control, which allows you to adjust how loud or soft your sound will be played back on your computer.

The final function of a preamp is impedance matching – this ensures that when you plug your mic into an audio interface, it will work correctly with no problems occurring during playback or recording sessions.

There are common questions about using external preamplifiers. Yes, it is possible to buy external preamps and connect their outputs to the audio interface to use. However, external preamps sound much better than internal preamps.

3. Connection type

Commonly, there are three types of connections:

  • USB: It is the most commonly used in low- and medium-quality interfaces. The biggest advantage is that most computers have USB ports, so it’s universal. While it’s not the fastest connection, its speed in ports 2.0 and 3.0 has positioned it as the preferred choice of manufacturers and users. 
  • Firewire: It’s an old connection that is failing. Interfaces with firewire still exist and are already from the discontinued generations. Most modern computers no longer have firewire ports built-in, and replacement cables are hard to come by. Also, its speeds are lower than newer USBs, so I don’t recommend buying the FireWire audio interface.
  • Thunderbolt: It is the fastest connection on the market, but not very common in normal computers. This is usually the connection that the higher-priced interfaces have integrated.

4. Price

The price will be determined by the type of audio interface you need. The more channels and better components, the higher the price. Be very selective in your needs, but don’t skimp too much. Interfaces under $100 will be of poor quality and less durable.

Nowadays, you can get a good audio interface for your home studio with an investment of $300 to $500, such as or . Of course, if your budget is high, you will find more quality audio interfaces like , , or .

Some brands will provide you with an incredible amount of inputs, outputs, and features at a reasonable price, but be aware that the quality will be very poor. It is best to strike a fair compromise between its features and the price.


Buying a firewire interface is not a good idea; it’s better to aim for a USB interface or Thunderbolt if you’re going big.

So as said in this article, if you do recording work, the audio interface is a must-have accessory for your home or studio. You need to have a piece of good knowledge of what is an audio interface and its importance. 

Now you know it. So no worry, go ahead and buy an audio interface now.

Thanks for reading, and I hope you find this information helpful.

For any doubts, “contact us through the comments sections, and I’ll be happy to answer any questions.

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