Software Analyzer of Audio Systems


Ing. Petr FrenštátskýIng. Jiří Schimmel, Ph.D


It is possible to download software here.


The software allows to obtain qualitative parameters of hardware audio devices and software audio effects which are implemented in VST modules. The hardware audio devices are connected to a personal computer via a sound card. For the communication is used ASIO technology. The application is capable to measure frequency and linear characteristics, distortion parameters such as THD, THD+N, SINAD, WHD, a rate of crosstalk and a signal-to-noise ratio. The implemented analyses consider AES17 standard, which specifies parameters of test signals and parameters of filters that are used for analyses.

The software contains a graphical user interface where a user is able to set appropriate parameters for a measurement. There is an option to select if we want to analyze an external effect or a VST effect. There is an internal signal generator within the application. It is capable to generate harmonic signals such as sin or sweep signals and noise signals – MLS or white noise. For each of the analysis there is an option to select a suitable test signal. For instance, a frequency characteristic can be obtained by exciting a device under a test with a logarithmic or a step harmonic sweep signal. Since we can use a non-professional sound card, a ration between analogue and digital units is not known in advance when a measurement of external effect is done. Due to this fact, there is a capability to calibrate a gain of the sound card to express amplitude with analogue units within the application.

The application had been developed following a client-server architecture, where the graphical user interface is developed apart from a core module where the analyses, ASIO and VST host applications had been implemented. The software had been developed in C++ using Qt5 multiplatform libraries.