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There's a field apparently called "stellar seismology" in which the frequency of light from the stars is converted into audio. See (and hear) an example here. Any ideas on how they do it? What about if I wanted to produce something that sounds more like music? Are there any techniques that do that?

Update: all the answers were useful. Unfortunately I can only mark one as the answer :-)

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Any ideas on how they do it?

Have you ever wondered how you can tune your radio into several stations by rotating the dial? The spectrum of light is part of the electromagnetic radio spectrum. Light forms a very small part of it: -

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In the middle of the above picture is visible light. To the left hand side there is radio and to the right hand side are gamma rays. If you just tune in to the "visible" part and convert the signal to an electrical waveform then you have what ostensibly is the "signal from a distant star? OK you'll need a very directional antenna but that technology has been around for centuries i.e. a telescope. Then use a photo-diode and amplifier and you get star noise.

I listened to the clip and apart from the very annoying advert for KFC, it sounded like pink noise at first. Then it changes as if the scientists had applied some low pass filtering. At a few intervals the sound changes again and to me it sounds like they were using filtering on the basic signal played at the beginning after the stupid advert.

I'd recommend starting with a pink noise source (broadly flat sound across the spectrum) and use some filtering that repeats rhythmically. Mess around until something captures your imagination as usable as music and then also try that filtering technique on the star-sound.

I'd bet there wouldn't be much difference so I'd stick with pink noise.

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Light has a frequency and sound has a frequency. While light is electromagnetic and sound is pressure waves, both have wave properties. If you take the frequencies of light and create a mapping to frequencies in audio, you can remap changes in color to changes in pitch of audible frequencies. It's relatively simple as it is basically just slowing down the speed of the light wave by multiple orders of magnitude and then outputting it as audible sound.

As far as producing music from it however, this is a bit trickier as it is probably fairly unlikely that there is any regular beat or rhythm or even consistent timing to the sound. At most, it could be used as samples in a typical techno/electronic music approach, but it would be difficult and require careful selection of samples to put together something resembling music. Getting a regular beat would be the first step and then trying to produce something that is melodically interesting would be the second.

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Interesting... As certain frequency combinations are generally pleasing to the ear (Think an octave, a 4th, a 5th, a major triad, etc.), there may also be pleasing (or interesting at least) light wave frequency combinations.
asside... I wonder, can light have a timbre?

That may at least be a neat place to start when trying to find something that approaches pleasing sonorities... aka music.

That is, maybe work backwards. Translate a pleasing sound into light waves with the frequency conversion. You may start to see what makes a pleasing sound.

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If you can record the light and determine the color, you can identify the frequency. Then, slow it down proportionally until it's at a comfortable listening frequency.

If you wanted it to be more musical, you can either clean the samples and use them in music (or don't clean them and make ambient music or ambient accompaniment to something), or you can pick and chose the lights you want to play, so it would be a series of lights translated to sound.

Interestingly, you can probably get a video, find the average color, then change that into frequencies. Thus, you can record the video as audio for any movie or video. If you wanted it to be stereo, you could divide the screen in two, by dimension, or by color.

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