I've heard this before! In some Nine Inch Nails tracks. I always thought it was white noise + bandpass + clipping or distortion.
> I always thought it was white noise + bandpass
That would be equivalent to this approach, right?
What Does Perlin Noise Sound Like?
11–20 of 32 posts
Re: What Does Perlin Noise Sound Like?
#12This sound kind of reminds me of one of these "Space Engine Sounds" on youtube, especially the Firefly/Serenity themed track.
I used to love it for sleeping, it's rather relaxing.
Re: What Does Perlin Noise Sound Like?
#13My initial reaction was like "Oh, like white noise!" I could not have been more wrong. There is very clear structure in Perlin Noise. Great write-up and I learned something.
The article doesn't adjust for the inherent lowpass/highpass/aliasing behavior of function parameter rate vs sample rate, which is responsible for most of the audible difference, especially the similarities to real life low-passed-noise situations (airplane cabin, high building) noted by the author. Still, I agree, you can hear some residual tones! Spectra of the 3 noise samples: http://imgur.com/a/gaiVm I haven't re…
The code does explicitly assign a frequency of 440 Hz to the parameter rate in the first case and 110, 220, 440 Hz in the second. The second, fractal noise example might have been more interesting to compare to the first one if the author had kept the "fundamental" at 440 Hz and added higher-frequency overtones.
Re: What Does Perlin Noise Sound Like?
#14My initial reaction was like "Oh, like white noise!" I could not have been more wrong. There is very clear structure in Perlin Noise. Great write-up and I learned something.
Perlin noise was explicitly designed to give a smooth, "natural" noise pattern; its spectral energy distribution is by design completely different from white noise. Makes sense that it sounds very different as well :)
Re: What Does Perlin Noise Sound Like?
#15My initial reaction was like "Oh, like white noise!" I could not have been more wrong. There is very clear structure in Perlin Noise. Great write-up and I learned something.
The article doesn't adjust for the inherent lowpass/highpass/aliasing behavior of function parameter rate vs sample rate, which is responsible for most of the audible difference, especially the similarities to real life low-passed-noise situations (airplane cabin, high building) noted by the author. Still, I agree, you can hear some residual tones! Spectra of the 3 noise samples: http://imgur.com/a/gaiVm I haven't re…
Thanks for the spectrograms! I'm not exactly sure which aliasing you're referring to... I'm trying to adjust the sampling rate of the noise function so that it maps to "real" seconds in a way that makes sense. By looking at the waveform in the audio editor, it looks exactly like a visual representation of 1D perlin noise to me (http://imgur.com/a/bM4tn). Looking at your spectrograms though, I'm seeing something in the higher-frequencies (and I think I can hear those as well), but I actually have no explanation for where those could have come from.
Re: What Does Perlin Noise Sound Like?
#16This sound kind of reminds me of one of these "Space Engine Sounds" on youtube, especially the Firefly/Serenity themed track. I used to love it for sleeping, it's rather relaxing.
To me the first sample sounded like some subway passing by but when you're still far away yet.
That said, after about 15 to 30s of attentive, continuous listening, it started making me increasingly uneasy, as I perceived the sound as being extremely oppressive and ominous, in a very chthonian way. I'm not going to try to listen to that any longer because I'm half sure that could almost turn into a panic attack of sorts or something. Really unsettling.
The second, fractal one didn't produce that effect unless I turned the volume way up, and even then, not as much.
Re: What Does Perlin Noise Sound Like?
#17It might be interesting to use Perlin noise to craft a melody by mapping the reals onto a musical scale.
In particular, it seems like it would have some nice properties for melodies since it will keep the melody in a comfortable range and won't throw in a bunch of large leaps.
Re: What Does Perlin Noise Sound Like?
#18LOL. I just finished putting up a pergola with a clear polycarbonate roof. The recommendation is to apply a foam adhesive tape to the purlins (battens) to prevent noise caused by movement of the sheets from thermal expansion. Ihttps://www.bunnings.com.au/suntuf-access-25mm-x-20m-purlin-... - I thought it was a strange topic for HN ;-)
Re: What Does Perlin Noise Sound Like?
#19Earlier quoted context omitted.
The article doesn't adjust for the inherent lowpass/highpass/aliasing behavior of function parameter rate vs sample rate, which is responsible for most of the audible difference, especially the similarities to real life low-passed-noise situations (airplane cabin, high building) noted by the author. Still, I agree, you can hear some residual tones! Spectra of the 3 noise samples: http://imgur.com/a/gaiVm I haven't re…
Thanks for the spectrograms! I'm not exactly sure which aliasing you're referring to... I'm trying to adjust the sampling rate of the noise function so that it maps to "real" seconds in a way that makes sense. By looking at the waveform in the audio editor, it looks exactly like a visual representation of 1D perlin noise to me ( http://imgur.com/a/bM4tn ). Looking at your spectrograms though, I'm seeing something in…
That's a completely reasonable thing to do, especially because it might allow you to pick up distortion due to interpolation.
However, you should do the same thing to the white noise [1] if you are going to compare them. If we write the white noise's continuous reconstruction [2] as a function of time, w(t), we could stretch out w(t) until it wiggles at about the same rate as the perlin noise, p(t), and then sample them together at a rate several times higher than that at which they wiggle. Both waveforms would then have the same "muffled roar" sound you get in airplanes, buildings, underwater, etc.
Another mundane explanation for the bands is that they might be "JPEG artifacts" for ogg's compression. Amplitude is logarithmic, so they're probably not as important as they look.
[1] To be pedantic we should call it band-limited white noise, because the sampling+reconstruction process limits the bandwidth, and infinite bandwidth white noise can't actually exist, because it has finite energy per bandwidth * infinite bandwidth = infinite energy. This isn't a theoretical problem. Oscilloscopes have fatter "no-signal" traces in proportion to their bandwidth, the resolution bandwidth ("RBW") of spectrum analyzers lifts the noise floor at higher settings, the field of thermodynamics fell apart in the "ultraviolet catastrophe" before we understood how quantum mechanics effectively limits the bandwidth of thermal radiation, etc.
[2] w(float t) rather than w(int n), obtained by interpolation. Sinx/x interpolation is the interpolation that gives 0 distortion and produces no higher spectral content. It's the time domain equivalent of doing a Fourier Transform, scaling the spectrum, and doing an Inverse Fourier Transform. IIRC Perlin noise is a spline, not sinx/x, so I'd expect its interpolation to produce higher harmonics. By applying perlin-like (spline?) interpolation and sinx/x interpolation to the white noise, you could isolate the audio effects due to the randomization vs the interpolation of the perlin noise. If you were so inclined :)
Re: What Does Perlin Noise Sound Like?
#20Unfortunately, the audio clips do not play in Safari mobile.
Why does Safari struggle to open files in common and free formats?