Technical Resources
With over 100 combined years of audio measurement experience, our team has created a wealth of technical papers, sequences, articles and other useful information to assist you with your audio test needs. Please browse the collection below, or filter by type of resource.
Measuring Digital MEMS Microphones – Frequency, Sensitivity, and Power Supply Rejection (PSR) Performance
This test suite contains 3 sequences to enable comprehensive testing of digital MEMS microphones:
- Measurement of frequency and sensitivity using a calibrated source
- Measurement of frequency using the ‘substitution method’, a solution for measuring frequency response where the source speaker cannot or is not equalized
- Measurement of power supply rejection (PSR) performance
Automotive Max SPL
The sequence measures the Max Sound Pressure Level (SPL) of a car infotainment system in the vehicle’s interior
The sequence uses a 6 microphone array mounted at either the driver or passenger locations. A 30 second pink noise stimulus having an RMS level of -12 dBFS is played through the infotainment system and captured by SoundCheck’s Multi-channel Real Time Analyzer (RTA). The Multi-channel RTA produces 6 RTA curves which are then power averaged to produce a Max SPL Spectrum. The spectrum is then power summed to produce a single value for Max SPL.
Microphone Acoustic Overload Point (AOP)
This sequence measures the acoustic overload point (AOP) of a microphone – the SPL required to produce 10% THD @ 1kHz from the microphone’s output.
A 1 kHz amplitude sweep from a calibrated source speaker is applied across a range from 120 dB SPL to 135 dB SPL.The recorded time waveform is then analyzed using the HarmonicTrak algorithm to produce a Fundamental and THD vs. Level curve. An intersection post processing function identifies where the THD curve intersects 10% and that level is is used in a limit step to produce a Pass/Fail AOP verdict.
RT60 Room Acoustics
The RT60 room acoustics sequence measures reverberation time and clarity of a room using multiple microphones to accurately characterize measurement environments. This is important for smart device testing as measurements of both speech recognition and audio output often need to be made in fully characterized rooms with known reverberation times and clarity. The method used in this sequence is fast, accurate, and made using fully calibrated signal paths. This sequence uses an omnidirectional speaker to play a Log Sweep from 250Hz – 15kHz and four microphones measure the impulse responses generated. These waveforms are analyzed using the Time Selective Response and room acoustics algorithms to calculate reverberation time (T20, T39, T60) and clarity (C7, C50 and C80) according to ISO 3382-1:2009.
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SoundCheck 19 New Features Video
In this short video, sales engineer Les Quindipan gives a brief overview and demonstration of the new features and functionality of SoundCheck 19, including the multichannel RTA, RT60 Room Acoustics module, AmpConnect 621 control, and more.
Measurement of Stereo Soundfield Parameters
The stereo soundfield sequence measures parameters such as Interaural level difference (ILD) and interaural cross-correlation (IACC) using a Head and Torso Simulator (HATS). The spectrum is measured at each ear and calculates interaural level differences (ILD), spectral balance, delay differences, and interaural cross-correlation (IACC). The measurements are made using different time windows, so that the direct, early, late or total parts are separated.
Several different signals are applied to the left and right inputs of the device under test (DUT), and the measurements are made with the HATS left and right ears. Up to 9 measurements in varying positions are made and saved. Results for each position are displayed, and on completion of the testing, means and standard deviations are shown.
TIA-5050 Test Sequence for Narrowband (NB) and Wideband (WB) Mobile Handset Phones
TIA 5050 is a US standard with measurement methods and requirements for the receive volume control performance of both narrowband (NB) and wideband (WB) mobile handset phones. The measurements include conversational gain, frequency response, and distortion. Measurements are made at both 2N and 8N handset application forces, with different requirements applied to each. Either Free Field (FF) or Diffuse Field (DF) can be chosen as the Listener Reference Point (LRP) for receive frequency response.
Display Tutorial
Our series of basic SoundCheck training instructional videos concludes with 7 short videos highlighting the different display options ranging from simply x-y graphs and tables to polar plots, and display customization, and of course how to use all these options in a sequence.
Part 1: Display Step Basics
Part 2: Display Configuration
Part 3: Graph Palettes
Part 4: X-Y and Waveform Graphs
Part 5: Tables, Text and Pictures
Part 6: Results
Part 7: Polar Plot
