Measurements and Spatial Audio
R2026bAudio Toolbox™ enables you to evaluate audio systems by generating test excitation signals, estimating impulse responses, and calculating industry-standard metrics.
You can also use Audio Toolbox features to work with spatial audio signals. Read head-related
transfer functions (HRTFs) stored in SOFA files, and interpolate HRTFs with
interpolateHRTF. Use ambisonicEncoderMatrix and ambisonicDecoderMatrix to encode and decode 3-D audio using
ambisonics.
Apps
| Impulse Response Measurer | Measure impulse response of audio system |
Functions
Properties
| Meter Properties | Audio Meter UI component (Since R2023b) |
Blocks
 | Loudness Meter | Standard-compliant loudness measurements |
Topics
- Measure and Manage Impulse Responses
Capture and analyze impulse response (IR) measurements by using the Impulse Response Measurer.
- Create an App to Play and Visualize Audio Files
Create an app in App Designer to play and visualize audio files.
- Surround Sound Matrix Encoding and Decoding
This example shows how to generate a stereo signal from a multichannel audio signal using matrix encoding, and how to recover the original channels from the stereo mix using matrix decoding.
- Audio Device Test Stimuli
Exercise a nonlinear system with common audio device stimuli and compare the advantages and disadvantages of the different stimuli.
- Analyze Ambisonic Decoders
Derive objective metrics to analyze the performance of an ambisonic decoder.
- Ambisonic Spatial Transformations
Apply spatial transformations to an ambisonic signal.
- Multicore Simulation of Acoustic Beamforming Using a Microphone Array
This example shows how to beamform signals received by an array of microphones to extract a desired speech signal in a noisy environment.
- Measuring Speech Intelligibility and Perceived Audio Quality with STOI and ViSQOL
Use the STOI and ViSQOL metrics to measure speech intelligibility and perceptual audio quality in speech and audio signals.
- Technical Standards Implemented in Audio Toolbox
Technical standards and common industry metrics implemented in Audio Toolbox.
Related Information
Featured Examples
Measuring Loudspeaker Nonlinearities Using Swept Sine Excitation
Simulate and measure loudspeaker nonlinearities using impzest, sweeptone, and Simscape™ Acoustics.
Evaluate Room Noise and Design for Compliance Using ANSI/ASA S12.2-2019
Evaluate the background noise of a room and design for compliance.
Evaluate Room Noise Using ANSI/ASA S12.2-2019 Criteria (Live Measurement)
Evaluate the background noise of a room using a live measurement.
Build an Impulse Response Measurement App
Create an application to measure impulse responses.
Comfort Distance and Distraction Distance (ISO 3382-3)
Compute the comfort distance and distraction distance for an open-office plan.
Model, Evaluate, and Design Acoustic Spaces
Learn how to model, analyze, and optimize the acoustics of an indoor space.
Visualize Ambisonic Sound Field
Visualize the directional information in an ambisonic signal.
Read, Analyze, and Process SOFA Files
Load a SOFA file, analyze the HRTF measurements, and use the measurements to spatialize an audio signal.
Audio Weighting Filters
Obtain A-weighting and C-weighting filters the weightingFilter System object™ in the Audio Toolbox™.
Sound Pressure Measurement of Octave Frequency Bands
Measure sound pressure levels of octave frequency bands using splMeter. An interactive app lets you adjust the frequency weighting, bandwidth, and audio source while viewing live measurements.
Active Noise Control with Simulink Real-Time
Design a real-time active noise control system using a Speedgoat® Simulink® Real-Time™ target.
Ambisonic Plugin Generation
This examples shows how to create ambisonic plugins using MATLAB® higher order ambisonic (HOA) demo functions. Ambisonics is a spatial audio technique which represents a three-dimensional sound field using spherical harmonics. This example contains an encoder plugin, a function to generate custom encoder plugins, a decoder plugin, and a function to generate custom decoder plugins. The customization of plugin generation enables a user to specify various ambisonic orders and various device lists for a given ambisonic configuration.
Ambisonic Binaural Decoding
Decode ambisonic audio into binaural audio using virtual loudspeakers. A virtual loudspeaker is a sound source positioned on the surface of a sphere, with the listener located at the center of the sphere. Each virtual loudspeaker has a pair of Head-Related Transfer Functions (HRTF) associated with it: one for the left ear and one for the right ear. The virtual loudspeaker locations along with the ambisonic order are used to calculate the ambisonic decoder matrix. The output of the decoder is filtered by the HRTFs corresponding to the virtual loudspeaker position. The signals from the left HRTFs are summed together and fed to the left ear. The signals from the right HRTFs are summed together and fed to the right ear. A block diagram of the audio signal flow is shown here.
Acoustic Beamforming Using a Microphone Array
Illustrates microphone array beamforming to extract desired speech signals in an interference-dominant, noisy environment. Such operations are useful to enhance speech signal quality for perception or further processing. For example, the noisy environment can be a trading room, and the microphone array can be mounted on the monitor of a trading computer. If the trading computer must accept speech commands from a trader, the beamformer operation is crucial to enhance the received speech quality and achieve the designed speech recognition accuracy.
Live Direction of Arrival Estimation with a Linear Microphone Array
Acquire and process live multichannel audio. It also presents a simple algorithm for estimating the Direction Of Arrival (DOA) of a sound source using multiple microphone pairs within a linear array.
Binaural Audio Rendering Using Head Tracking
Track head orientation by fusing data received from an IMU, and then control the direction of arrival of a sound source by applying head-related transfer functions (HRTF).
Measure Impulse Response of an Audio System
The impulse response (IR) is an important tool for characterizing or representing a linear time-invariant (LTI) system. The impulseResponseMeasurer enables you to measure and capture the impulse response of audio systems, including:
Acoustic Echo Cancellation (AEC)
Apply adaptive filters to acoustic echo cancellation (AEC).
