Impulse Response

Giới Thiệu · Impulse Response

Turn your Android smartphone into a powerful tool for measuring the frequency response of audio systems.The Impulse Response app generates an MLS signal from the speaker (or headset jack) and records it via the microphone, and then calculates the response of the system (dB level) as a function of frequency.The display shows the realtime spectral response together with the derived impulse signal. Thespectrum can be shown in 1/1, 1/3 or 1/6 ISO octave bands, or in full pixel resolution. Thelevel (dB), frequency (HZ) and impulse (time) scales can be adjusted via the Menu.The impulse signal can be averaged, if desired. Spectrum response data can be saved to theSD card for later retrieval, or offline processing (they are simple text files easily importedinto e.g. Excel), and shown alongside the realtime spectrum data.To test the response of audio equipment, the MLS signal may be fed into its Line In inputvia a cable attached to the phone's headset jack. If a higher quality external microphoneis to be used it can easily be attached using a Y breakout connector in the headset jack.The MLS (Maximum Length Sequence) signal has the advantage over a simple pulse in that ithas a greater power density and thus causes the equipment under test to operate in a moreusual regime. This app uses a Fast Hadamard Transform to do the necessary convolution ofthe recorded signal with the MLS in order to extract the impulse response of the system.This is the initial release of Impulse Response - feedback and/or questions/problems aremost welcome - please send email.(If you require an Android-based SPL meter, Signal Generator, RT60 meter and Spectrum Analyser,please see our AudioTool app, also in Google Play.)Content rating: Everyone