USB microphones are different from conventional ones because they join both preamplification and digitalization stages into one single unit. Its design is to interface perfectly with a computer using only a digital connection. This type of microphones include a sensor component within the same device. There are also ADC interfaces, common in conventional analog microphones. These microphones involve preamplification and anti-aliasing filtering, as well as analog-to-digital conversion—all in one single unit.
USB Microphones Explained
The Basics
To begin with, the output of a USB microphone gathers the digital signal of a USB microphone. It happens through an external ADC interface, too. Then, the acquired signal is stored directly into a computer file. In terms of their components, USB Mics include a pad, an internal shock mount, and a bass roll-off, as well as a variety of pickup patterns.
USB microphones use a converter, also known as an adaptor, to connect any dynamic or capacitor XLR mic to a computer. Converters might include a preamplifier, level controls for balancing and playback, phantom power, and headphone monitoring.
The quality of USB microphones ranges from low to high. Plus, they have the same performance issues as traditional analog microphones.
The Common Issues
Frequency range is the most common issue in USB mics. However, this is not the only one: the user may also have problems with dynamic range and directionality. There are digitalization performance issues as well. These include sample rate, dynamic range, bit depth, and anti-aliasing filtering. A considerably high dynamic range of the USB microphone or the ADC interface will result in clipping of the captured signal. (It’s worth mentioning that both capture software and recording software are compatible with USB microphones and ADC interfaces, as they tend to support a diversity of traditional sampling rates.)
Adding to this list, sound quality, in particular latency—the period of time it takes for data to get from one point to another—tends to be a common issue among USB mics. And the frequency response among them varies.
Low-cost USB microphones and external ADC interfaces tend to have poor performance, as well as excessive digitalization and self-noise. Higher quality USB mics and external ADC interfaces usually provide documentation regarding the performance specifications. When this information is not available, the user should use the device very carefully.
