Understanding the Functioning of an Audio Interface

An audio interface is a device that connects to a computer or mobile device, such as a phone or tablet. Its primary function is to convert analog audio signals to digital and vice versa.

To achieve this, the device is equipped with analog-to-digital (AD) and digital-to-analog (DA) converters.

AD stands for Analog to Digital.

DA stands for Digital to Analog.

The accuracy of these converters greatly influences the quality of the audio output. Inexpensive converters often introduce small errors, resulting in incorrect sampling. This phenomenon, known as jitter, occurs when a sample is taken at the wrong moment.

Consequently, the quality of the converters significantly impacts the price of an audio interface. Higher-quality converters are generally more expensive.

It is worth noting that there are audio interfaces that solely transmit and receive digital signals. In such cases, external converters are used for conversion, if necessary.

The Limitations of Internal Sound Cards

The internal sound card of a computer is rarely comparable in quality to a high-quality external audio interface. Therefore, it is seldom used for audio recordings. Additionally, internal sound cards typically lack a good microphone preamp and phantom power required to connect popular condenser microphones.

Microphone Preamp and Phantom Power

An excellent audio interface with a microphone input should ideally have balanced inputs, such as XLR. Professional microphones also utilize XLR connections, allowing them to be connected using a standard microphone cable.

The weak output signal of a microphone needs to be amplified to a usable level without introducing noise, such as hissing. This amplification is achieved through the microphone preamp, which is a highly sensitive and costly component. Consequently, higher quality preamps come at a slightly higher price. However, companies like Focusrite have been producing top-quality microphone preamps for their high-end equipment for decades, enabling them to offer relatively affordable audio interfaces that are immensely popular.

Even budget brands like Behringer incorporate high-quality preamps from Midas, a reputable brand they acquired. This allows them to combine affordable hardware with partially high-quality technology.

Reducing Latency and Delay

One of the crucial functions of an audio interface is recording. Since recording is often done track by track, it is essential to hear the material being recorded simultaneously with the signal being recorded.

Most interfaces offer a monitoring function that allows direct listening to the signal without passing it entirely through the computer, thereby avoiding delays.

However, if you wish to monitor the signal with computer effects, you will need a fast computer with ample RAM memory. Additionally, a special protocol, known as ASIO, ensures rapid communication between the audio interface and the computer in Windows-based systems.

Below are some highly recommended audio interfaces that enable top-quality recordings.