BPM Skills is reader-supported. When you purchase through links on our site, we may earn an affiliate commission. Learn more

What Is an Audio Interface? [Everything You Need to Know]

What Is an Audio Interface_ Everything You Need to Know

If you are interested in digital recording and music production, you have probably encountered mentions of an audio interface.

In essence, an audio interface serves as the connection for your audio to your computer. It converts audio signals from analog to digital and vice versa for you to work conveniently with.

Here is everything you need to know about what is an audio interface and its related concepts.

Table of Contents

What Does an Audio Interface Do?

What Does an Audio Interface Do

You will need an audio interface if you want to record guitar, vocals, or any other instrument. You can connect this to your computer and studio monitors.

An audio interface is a device that allows your microphones, keyboards, and instruments to connect to your computer or digital audio workstation (DAW).

Think of it as a converter!

Your input devices, such as your microphones and instruments, produce analog signals. Audio interfaces convert these signals into digital signals for your computer to process.

They also work the other way around!

Communication and processing between devices will not be possible without an audio interface.

This makes it a piece of essential equipment in recording and producing music. It allows you to process audio into your recording software and playback what you have recorded.

Aside from these, it ENHANCES the sound quality of the audio you are recording.

The sound quality you get from an audio interface is of a higher level than that from an ordinary sound card.

How Do Audio Interfaces Work?

How Do Audio Interfaces Work

Conversion is the key function among all the many others that audio interfaces provide.

The traditional recording was purely analog. Everything happened at the mixing desk, which produced the tape records.

Audio recording today is different. It involves various signals, of which an audio interface processes both digital and analog signals.

  • Signals that come from a MIDI keyboard, microphone, and other instruments are analog.
  • An audio interface converts these into digital, which the computer can process. Analog to digital conversion is referred to as ADC.

You can now easily mix and modify sounds once these signals are processed in your computer or sequencer.

The same audio interface converts them back to analog for you to hear from your headphones and speaker outputs. Digital to analog conversion is referred to as DAC.

The majority of audio interfaces have several channels for each ADC and DAC.

In general, the conversion of many signals is possible because of the audio interface.

With the conversion of signals, gain boosting of specific signals also occurs. Gain boosting is when the conversion of signals results in a HIGHER quality of sound.

Several audio interfaces also feature built-in microphone preamps. Along with gain boosting, they allow you to capture studio-quality recordings.

Why Do You Need an Audio Interface?

Why Do You Need an Audio Interface-

The focal point of your recording studio has to be your audio interface. It connects to your computer, studio monitors, microphones, guitars, and other musical instruments.

You will need a good audio interface if you want to take your audio recording and monitoring up to a higher level.

Vs. Built-in Sound Cards

An audio interface is way more upgraded than a built-in sound card.

It can record and monitor many channels at once and has lesser latency and more connectivity options.

Audio interfaces are bigger than sound cards that are built into your computer. Its size gives you more options in terms of input types.

Several come with MIDI in and out for a keyboard controller connection.

Other more professional recording equipment, such as a 1/4″ jack guitar and a full XLR microphone input, can connect to an audio interface more than to a built-in sound card.

Another advantage is the higher audio quality it produces. Professional quality audio recording and playback are only possible with an audio interface.

A built-in sound card only has basic features. The number of signals and channels it can process is limited and only has a few connectivity options.

What Are the Types of Connectivity for Audio Interfaces?

What Are the Types of Connectivity for Audio Interfaces-

Many audio interfaces are available in the market today.

You can choose the right audio interface for you based on the connectivity that your computer can accommodate and your specific needs.

USB Audio Interfaces

Many devices, such as phones, cameras, and printers, connect to the computer through the Universal Serial Bus. It is commonly called the USB.

As we all know, it is easy to operate. It is plug-and-play connectivity, and you will not need an external power supply because the USB itself is a power source.

Because of this easy operation, most audio interfaces’ connectivity is also through USB.

USB audio interfaces are the EASIEST to use. Their convenience makes them the best-selling type of audio interface.

The latest version of USBs is USB 3.0. It will give you a faster connection than the USB 2.0 audio interfaces.

However, many sellers retail USB 2.0 audio interfaces at cheaper prices to get rid of old inventory.

FireWire Audio Interfaces

A FireWire audio interface will give you a substantially bigger capacity than a USB audio interface.

It features the ability to process bigger audio data sizes while keeping latency low.

On top of this, it permits more expansion as you can have more inputs and outputs. It can accommodate more units on its interface.

You can choose between two FireWire types: FireWire 800 and FireWire 400. Your choice depends on your computer port.

Your FireWire audio interface should fit into the port of your DAW or computer.

Take extra precautions when using FireWire audio interfaces. Only turn your computer on AFTER you plug in your FireWire cable.

Doing otherwise may cause damage to your FireWire audio interface.

Thunderbolt Audio Interfaces

FireWire ports have become rare nowadays. Newer computer models, especially Macs, can no longer accommodate FireWire audio interfaces.

Apple, the company that manufactures Macs, has developed a new input and output technology. They call this new protocol Thunderbolt.

Thunderbolt audio interfaces were at first way more expensive than other types of audio interfaces. They were even considered a luxury at some point!

Thanks to other electronics manufacturers, reasonably priced Thunderbolt audio interfaces are now available.



How Many Inputs Do I Need?

The number of inputs and outputs you need depends on the equipment you want to connect to your computer to produce the music and sounds that you want.

  • One input can be enough if you are aiming for a home studio for your solo performances. This is good for only one microphone if you are recording vocals only OR one instrument for a solo performance.
  • Meanwhile, two inputs is needed to mix music if you are a DJ.

However, we recommend you have an audio interface with two or more inputs that can function simultaneously.

A higher number of inputs allows for more expansion and versatility!

You can start and do away with basic recording and producing with one input.

If you need to record audio from a CD player or keyboard that is commonly stereo, your audio interface will need at least two inputs.

Several audio interfaces available in the market today have more than one input, like combo jacks and built-in preamps.

These can accommodate both an instrument and a microphone in one input.

Bigger audio interfaces have a higher number of inputs. They can have as many as 8 built-in preamps. This is the minimum number of inputs you need to record band music.

You can go further and stack one or two more audio interfaces to have more inputs that record simultaneously.

Take note of the types of inputs that you will need. It will depend on the device or instrument that you want to connect to your computer.

  1. Built-in Mic Preamp and Phantom Power – You will need an audio interface with either or both of these types of inputs to operate condenser microphones. We recommend this type of microphone for recording vocals.
  2. Line-Level Input – Instruments like your guitar will need a line-level input to connect to your audio interface. Most audio interfaces have this type of input.

How Many Outputs Do I Need?

How many outputs you need on your audio interface depends on the music you want to record and produce. The majority of interfaces have an equal number of inputs and outputs.

An audio interface typically has two outputs to connect to your monitor speakers.

  1. One output is dedicated to the left speaker, while the other is to the right speaker.
  2. A pair of outputs is enough for a stereo speaker setup.

These outputs can also connect to your headphone jack. A few interfaces may have dual headphone outputs.

A higher number of outputs has its advantages. You can level up your music recording and production to a surround-sound setup for better listening and monitoring.

For example, you can have 8 outputs. This will allow you to connect 7 speakers and 1 sub-woofer for a surround-system setup.

This is more useful for music producers and film composers. A singer-songwriter can do away with fewer outputs.

PRO TIP: Choose an audio interface with balanced outputs and use balanced cables. The cable and cores will pick up any interference, which will be canceled out. Possible ground-loop problems are eliminated because the screen is not part of the signal path.

What Is Phantom Power?

The 48v button on your audio interface stands for phantom power. Switching this button on delivers 48 volts of additional electrical charge to your device.

A condenser microphone needs this power supply to function. Other microphone types, such as dynamic and ribbon microphones, do not need phantom power.

Other devices that may need this power supply are audio recorders and video cameras.

The electrical charge that phantom power delivers is direct current (DC). It is a unidirectional flow of electric current that does not change in amperage.

It travels through the XLR cable of the microphone or device and powers the active electronic circuitry within its components, specifically its backplate and diaphragm.

Without it, your condenser microphone or phantom power-reliant device will not operate at all!

Along with phantom power, mic preamps and XLR cables raise your condenser mic to mic-level.

This will give you a studio-quality recording in contrast to the rugged and natural sounds that other microphone types produce.

What Converters Should You Consider?

Conversion is the primary function of audio interfaces.

Most, if not all, interfaces have two ways of converting signals. These are analog to digital and the other way around, digital to analog.

Most interfaces are designed with different conversion features.

The important features you should consider when you look into audio interfaces are dynamic range, sample rate, and bit-depth.

Sample Rate

Sample rate or sampling rate is the FREQUENCY of samples in a digital recording. It is the number of audio samples per second measured in hertz (Hz) or kilohertz (kHz).

The common sample rate for music and video production is from 44 kHz to 48 kHz. It is better to have a higher sample rate.

Bit Depth

When an audio interface samples signals, the signal information is stored in bits. Bit depth describes the storage capacity for the signal information.

It translates to the resolution of the audio data that is recorded and stored in an audio file.

The standard CD recording has a resolution of 16 bits. Most audio interfaces today have a maximum bit depth of 24 bits.

An audio file of 24 bits can capture more details and accuracy than an audio file of 16 bits. 24-bit audio has higher quality than 16-bit audio.

Dynamic Range

Dynamic range refers to the scope between the least audible and most audible signals that an audio interface can convert. It is quantified in decibels (dB).

A 16-bit audio file can have a dynamic range of 96 dB. A 24-bit audio file can have up to 144 dB.

What Are Preamps?

The term preamp is short for a preamplifier, also called mic pres. They are commonly a built-in feature of an audio interface.

Their function is to amplify a weak signal to line level.

They capture weak sound signals from a microphone or musical instrument and give them a BOOST up to a decent level for recording.

A good preamp gives a selective boost, meaning that it should produce low-noise and high-quality sound signals.

A built-in preamp that comes with an audio interface is enough for home recording. Higher-quality preamps have higher prices.

Additionally, they may have to be external units and therefore not built into your audio interface anymore.

Do I Need an Audio Interface For a USB Mic?

You may NOT need an audio interface for a USB mic anymore.

Technically, a USB condenser mic is a type of microphone with a built-in audio interface.

Like a USB audio interface, a USB mic is a plug-and-play device. You only have to plug it into a USB port, and it can function fully.

We recommend this for solo music performers and singer-songwriters. It is enough for a basic home recording studio.

USB condenser mics of higher quality feature a specific headphone output. This dedicated output minimizes processing delays and latency.

If you aim for real-time monitoring during a recording session, we recommend that you get a higher-end USB condenser mic.

With only one USB microphone, you can record a duet and even a band. You may have less control because you are only using one microphone, but it is cost-efficient.

This works if you only aim for basic functionality in a recording studio.

What is Direct Monitoring?

Direct monitoring is referred to as zero latency monitoring because this feature allows you to monitor the input signal with near-zero latency.

This works because your audio interface captures an input signal and sends it directly to your headphone or speaker outputs.

It is essentially a switch to bypass your computer or DAW to eliminate latency.

When you turn this feature on, you will hear your audio right away without any notable delay.

Let us say you are recording vocals. You will instantly hear the sound from your headphones or speakers.

Aside from directing sound output, this feature directs signals to your computer or DAW for recording. Direct monitoring manages the combination of these two.

A good audio interface has the LEAST latency and at the same does not drain your CPU power.

Is an Audio Interface the Same as a Sound Card?

An audio interface and a sound card have the same basic functionality.

They both get sounds in and out of your computer, tablet, or DAW to translate to a digital signal and back to its analog form.

However, an audio interface is an external device that connects to your sound-processing equipment. It is not built into the design of your computer, unlike a sound card.

Moreover, an audio interface can accommodate more types of inputs and outputs because of its size.

As a result, it can record and produce higher quality audio than a sound card.

We recommend getting an audio interface if you want to take your recording and production to a higher level, as an ordinary sound card is not enough.

Final Thoughts

Final Thoughts

For you to remember what is an audio interface, it is a converter that links your microphones and musical instruments to your computer and speakers.

It converts audio signals for you to process in your digital audio workstation and to hear through your speakers.

Enjoy recording and experimenting with higher-quality sounds with an audio interface.

About the author


After becoming obsessed with the beats that were the soundtrack to his youth, Nick became a student of hip hop, digging for vinyl records, looking for the perfect break. Before he got his hands on an MPC sampler, he would mash these records, beats, and breaks into mixtapes and live DJ sets.