If you are a musician, singer-songwriter, engineer/producer, podcaster, streamer, gamer, or content creator who is serious about audio recording or production, then you need an audio interface that will help you get professional-sounding results and make your workflow more efficient. Audio interfaces are essential pieces of equipment that come in a variety of shapes and sizes, but they all have the same basic functions: They convert analog signals from microphones, instruments, and other audio gear into digital audio that the recording software (known as a digital audio workstation, or DAW) on your computer or mobile device can process. They also convert that digital audio back to analog, so you can monitor your audio through speakers and headphones.
When choosing an audio interface, there are a few key factors to consider. This guide will review these factors and help you narrow down your choices to find the audio interface that's right for you.
Benefits of Using an Audio interface
Improve the quality of your audio: An audio interface can improve the sound quality of your recordings by providing better analog to digital (A/D) and digital to analog (D/A) conversion than your computer's built-in sound card. This is especially noticeable if you are using high-quality microphones or instruments.
More flexible workflow: Audio interfaces can function as the hub of your studio, giving you more flexibility in your recording setup. You can connect multiple microphones, instruments, mixers, and monitoring devices to your computer. Some interfaces come with MIDI ports and even AES, S/PDIF, or ADAT digital inputs/outputs ports that allow you to expand your setup as your needs evolve.
Quality of A/D and D/A Converters
The A/D and D/A converters are the bridge between the analog world and digital world. The quality of their design has the most significant impact on the sound quality of an audio interface. High-quality converters will produce a clearer, more transparent sound with more detail and a more natural, lifelike feel. Look for brand-name interfaces with dynamic-range specs of 115 dB or above (the higher, the better).
Next to the converters, microphone preamplifiers are the most important components of an audio interface. A good preamp will amplify the microphone signal without adding any unwanted noise and distortion, making it sound more realistic and engaging, while a low-quality preamp can make the sound muddy and lifeless.
Invest in an interface with preamps that deliver plenty of gain and low noise. This will ensure that your dynamic mics sound great, even when they are placed far away from the sound source. This will also allow you to capture the full potential of your high-end condenser and tube mics and produce recordings that sound their best.
Computer and Mobile-Device Connectivity + Powering Options
There are two main options for connecting your audio interface to your computer: USB and Thunderbolt™. USB is the most popular option because most Windows and Mac computers come equipped with USB ports. The advantage of using a USB is that there are many interfaces designed to run on USB bus power from your computer (rather than an external power supply), which is excellent if you plan on doing mobile recording with your laptop.
Thunderbolt™ is a connectivity standard that offers faster transfer speeds than USB, resulting in lower latency (the delay between when you sing a note and when you hear it). It is also more expensive, generally requires a power supply, and not all computers can connect to it. You’ll need a Mac computer (all MacBooks and iMacs since 2007 have Thunderbolt™ ports) or a high-end Windows computer equipped with a Thunderbolt™ port. Audio interfaces with Thunderbolt™ connectivity are typically used by professional audio engineers and producers.
Not all audio interfaces are compatible with iOS and Android devices. But, if you’re taking your productions from the bedroom studio into the larger world, look for a mobile interface that’s small, powered by USB, Lightning, or disposable batteries, and compatible with your smartphone or tablet. You’ll need to get a Lightning to USB Camera Adapter for your iPhone/iPad or a USB OTG cable for your Android device.
Types of Analog Inputs and Outputs, and How Many Do I need?
How many analog inputs/outputs (I/O) you need really depends on the number of instruments and voices/vocals you want to record simultaneously. First, let’s look at the different types of inputs and their associated connectors:
Combo XLR / 1/4" Input Jack: This versatile connector combines an XLR connector with a 1/4" connector. Use it to plug in a microphone or a mixer through the XLR, or an electric instrument or media player through the 1/4". The combo jack provides balanced connections to help reduce noise and interference over long cable runs.
Dedicated 1/4" Hi-Z Input Jack: Connecting instruments with high impedance like electric guitars or basses to standard 1/4" inputs can result in poor signal quality. That’s why some interfaces offer a dedicated 1/4" Hi-Z instrument input (sometimes called DI) designed to preserve the sound quality of your instruments. Other interfaces have a switchable Hi-Z setting for instruments connected to the combo jack.
1/4" Line-Input Jack: This jack provides a balanced connection to input a line-level signal from a variety of devices like mixers, drum machines, or external effect processors.
1/4" Monitor Output Jacks: These jacks come in pairs. They provide a balanced connection to output a line-level signal, and they are typically used to connect the interface to speakers or to a mixer.
1/4" Lone Output Jacks: Some interfaces offer additional line outputs for routing different channels of audio to different speakers, or destinations like external signal processors.
1/4" Headphone Output: This jack allows you to monitor your audio signal through headphones. Some interfaces provide two headphone jacks with individually adjustable levels.
Even if you're just starting out as a podcaster, singer/songwriter, or electronic musician, we recommend getting an audio interface with at least two inputs. You may only need one input now, but you may find yourself wanting to record two microphones or a mic and an instrument simultaneously in the future. For example, electronic musicians may need to capture the outputs from a media player or keyboard, which are usually stereo, meaning you'll need at least two inputs on your audio interface.
For larger podcasts, or if want to record more instruments, mics, or bass, a 4-input interface will let you capture more sources at once. Also, most 4-input interfaces feature additional outputs for external processors and monitoring capabilities.
If you want to record a drum set or a full band you’re going to need as many inputs as possible. We recommend you get at least eight microphone inputs.
Bit-Depth, Sampling Rate
Bit depth: The bit depth of an interface is the number of bits used to represent each sample of audio. A higher bit depth will reveal more of the subtle nuances in the sound. If you record at 16-bit, the quieter sections of your audio will tend to be noisy and less clear. 24-bit audio is considered the professional standard and is highly recommended. Some interfaces offer 32-bit float technology to capture loud, unexpected sounds without clipping, but it produces larger files than 24-bit audio.
Sample rate: The sample rate is the number of times per second an audio interface captures the sound signal. It is measured in kilohertz (kHz). Sample rates range from 44.1 kHz to 192 kHz. Higher sample rates result in more realistic, high-frequency sounds, especially noticeable in cymbals and hi-hats.
44.1 kHz is the standard sample rate for CDs and most streaming services. It is more than enough to capture and reproduce every sound that humans can hear. However, audio professionals often choose to work at 88.2 kHz for music, as this can help to capture more detail in the sound.
48 and 96 kHz are the standard sample rate for video applications. They are also a good choice for general-purpose audio recording, because they offer a good balance between sound quality and file size.
176.4 and 192 kHz are even higher sample rates that are mainly used for high-end mastering applications. 192 kHz can be beneficial when slowing down audio for sound design effects. They can help to capture even more detail in the sound, but they also produce very large files. As a result, they are not practical for most users.
Future-Proof Your Interface with Digital I/O
Digital I/O is not a priority when you are just starting out, but it can be very helpful in the future. Common types of digital connections are ADAT, S/PDIF, and AES/EBU. If your audio interface has a standard ADAT I/O, you can easily expand your system by connecting an ADAT-equipped 8-channel mic pre. This will give you 8 extra channels, which is enough to record a band. AES/EBU and S/PDIF provide high-quality, stereo audio connectivity to a digital mixer or recorder.
Other Features to Consider
Phantom power: If you plan to use condenser microphones, ensure the interface provides +48V phantom power to power them.
MIDI connectors: If you use an older keyboard, sampler, or drum machine that doesn’t have a USB connection, you’ll probably want an audio interface that has 5-pin MIDI connections.
Virtual Loopback for streaming: Loopback recording is a feature that allows you to mix audio from other apps running on your computer with the audio you are currently recording. This can be useful for a variety of purposes, such as adding bumper music or other pre-recorded audio to a podcast in real time, or for bringing in audio from a Zoom or Skype call.
Control Apps: Some interfaces come with their own Control app that let you control all their functions from your laptop or mobile device. The apps offer features like voice processing, automatic gain setting, reverb, and compression, helpful to streamline the workflow and make it easier to get the desired sound.
Bundled Software: Audio interfaces often come with free music-production software that includes a DAW (usually “lite” versions of pro software) and plug-ins. DAWs are software that allow you to record, edit, and mix audio. Plug-ins are software that can add effects to your audio, such as reverb or guitar-amp simulations. The appeal of the free software will depend on what types of music or other content you are producing.
Meter Design: Metering is a critical tool for monitoring and ensuring the quality of your audio recordings. Look for an interface with easy-to-read meters.
Build Quality and Durability: Look for a well-built and durable interface that can withstand the demands of your recording environment.
Form Factor and Portability: Consider whether you need a rack-mounted interface, or a compact portable unit based on your recording setup and mobility requirements.
You don't need to spend a lot of money on a high-end interface with all the bells and whistles. A simple interface with a few inputs and outputs will be sufficient for most beginners.
There are many audio interfaces on the market. With a little effort, you can find an affordable interface that will help you take your audio recordings to the next level. We hope you found this guide helpful! If you have any questions, comments, or concerns, let us know down below.