posted 06 February 2010 11:21            

I have been getting interesting results when experimenting with the synthetic spectrum from array prototype lately, but as soon as I start editing the amp or frequencies window (i.e. changing its default values) I get either temporal deafness by some unforeseen brutal outburst of noise terror or just uninteresting hum.

As far as my limited knowledge about this goes, this prototype simulates a synthetic spectrum sort of like a parametric function right ? Now basically Im asking if there are any guidelines as to what kinds of spectrums one wants to simulate here...im guessing random amp and freq entries off the back of ones head wont cut it here, right ?

sorry if its a stupid question

posted 06 February 2010 12:59            

For example, if you were to set the Amplitudes array to:

code:

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{1 to: 128 collect: [ :i | 1.0 / i]}

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then the larger the harmonic number, i, the smaller the amplitude, 1.0/i. In the SyntheticSpectrumFromArray, set Envelope to a hot control like !Envelope, so you can attenuate the 128 sine waves.

Then if you set the Frequencies to:

code:

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{1 to: 128 collect: [:i | i * !FreqLow hz]}

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the frequencies would be harmonics of !FreqLow (integer multiples of a fundamental of !FreqLow).

Static spectra, no matter what the frequency and amplitude content, quickly end up sounding like mechanical buzzes. So another tip would be to include a little random jitter or variation in the amplitudes (and/or frequencies) to make the sound more "lively". In the physical world, a static spectrum is pretty rare.

For example, if in the Frequencies field you put:

code:

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{1 to: 128 collect: [:i | i * !FreqLow hz + ((1 s random smooth: 1 s) * 100 hz)]}

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you would have a basic harmonic spectrum but once per second, each harmonic would have a random number of hertz added to or subtracted from it (plus or minus 100 hz). The random number is smoothed so you hear the harmonics sliding around continuously. To reduce the deviation, change 100 hz to a smaller value like 10 hz (but I like the larger deviations better!