Pseudo-Random Noise

John Atkinson runs a set of measurements on the Vivid Audio G1Giya. Here, we see the Giya turning at five degree intervals, while a pseudo-random series of pulses is used to calculate impulse response.

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John Atkinson's picture

While DRA Labs MLSSA measurement signal sounds like noise, it is in fact a pseudo-random series of binary pulses. The computer compares what it sent to the speaker with what it received back from the microphone, and by performing a cross-correlation operation on the 2 signals, it can calculate the speaker's impulse response. FFT techniques can then generate the speaker's frequency response, step response, cumulative spectral decay plot, etc, from the impulse response.

KBK's picture

I guess six samples is enough to drop the S/N ratio to an acceptable level for a quick plot and look-see at the horizontal dispersion in the midband/crossover-region and up.