A microphone capsule with high AOP can help speech recognition systems in noisy environments, where the speech signal itself may not be loud, but other interferences are present.
For example, in voice-controlled home entertainment systems, the speakers are close to the microphone, and the digital assistant may output loud music or voice information.
A high AOP helps to reduce distortion and improve noise and echo cancellation.
Distance and Signal-to-Noise Ratio (SNR)
The farther the distance from the speech source, the lower the signal-to-noise ratio (SNR) of the signal sent to the ASR algorithm. Therefore, when the expected capture distance is longer, the microphone capsule should have a higher SNR.
Key Functionality of Speech Recognition Systems
The key function of a speech recognition system is its ability to ignore sounds and noises that are not part of the speech to be transcribed.
By excluding unwanted sounds from the signal, it can also improve audio/video capture and communication quality between individuals.
The goal is to increase the SNR of the microphone capsule, where SNR is the ratio of the desired sound (signal) to the harmful environmental sounds (noise).
Microphones for Live Broadcasting
Noise cancellation and directionality can be achieved by combining multiple microphone capsules with algorithms.
Directional microphone systems (such as beamforming) can focus the microphone's sensitivity on the desired direction and highlight the intended sound source.
Unwanted sounds can also be eliminated based on parameters (e.g., level difference between two microphones), with blind source separation being a more complex noise reduction system.
This system can eliminate noise regardless of direction, distance, or position. All these noise cancellation methods benefit from the accuracy and high quality of the signals they receive.
Microphone Requirements for Optimizing Noise Cancellation
To optimize the functionality of noise cancellation algorithms, the microphones used in the system should have the same properties.
Microphone-to-microphone matching is critical. The smaller the differences in sensitivity, phase behavior, and delay between microphone capsules, the better the system will perform.
