Stephen Mejias

Pseudo-Random Noise

Stephen Mejias  |  Apr 23, 2010

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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COMMENTS
John Atkinson's picture
Submitted by John Atkinson (not verified) on April 25, 2010 - 6:57am

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
Submitted by KBK (not verified) on April 25, 2010 - 11:25am

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.

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