Posts tagged as «Pitch perception»

SoME 2010 Nov: Encoded transmission

Sound Of the Month Edition

Message right to your brain

Sound perception graph

Understanding sound impact on human mind

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Before reading further, please listen to the above sample. …read more >>

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SoME 2010 May: Frequency of Chaos

Sound Of the Month Edition

Transition from random pitch sliding into pinkish noise

Spectrogram of random walk with rising temperature

880 Hz frequency randomized with standard variance of 1 octave and rising change rate

I took a simple 880 Hz sine wave and applied noise of standard variation = 1 octave.
At the beginning the random changes are slow – you can clearly hear the sliding tone. As the rate of changes gains more speed human ear tend to loose track of the tone and start hearing burping sounds. In the end, when the temperature gets really high (higher than tone frequency), the whole wave melts down into one uniform noise.

It’s just like blending a smoothie from an audio tone :)

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Falasol Timbre project zipped file: FrequencyOfChaos

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SoME 2010 March: Nyquist frequency

Sound Of the Month Edition

This is what you get when you mess with Nyquist frequency!

Nyquist frequency

Glissando from 422400 to 422,4Hz with sampling frequency of 44000Hz

In the analog world the hyperbola from the right side of the graph would go all the way up. You actually wouldn’t be able to hear such high pitches, but you’d see a nice hockey stick on the spectrogram. However digital sampling is not able to handle frequencies higher than half of it’s own frequency – that’s the Nyquist theorem. And that’s when the weird things start to happen :)

Sounds like a plasma cannon:

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Falasol Timbre project file: Nyquist effect.timbre

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Experiments: Pitch perception

Natural or instrumental sounds usually consist of complex harmonic structure. In this post I’ll try to explore basics of human pitch perception.

According to wikipedia: “Pitch represents the perceived fundamental frequency of a sound”. Let’s try to validate it on a simple example – sample consisting of 4 harmonics – integer multiples of 440Hz: 440Hz, 880Hz, 1320Hz, 1760Hz. Below you can find a recording of the sample repeated four times, each time followed by a single successive harmonic:

Sound followed by each of 4 harmonics

Sound followed by each of 4 harmonics

4 harmonics (Timbre file – pitch 440 with 4 harmonics) …read more >>

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