FreakSpex

[video_piglet]

This is a frequency spectrum I made for VJ use, particularly in Resolume. My aim was to make a spectrum that would be fun to watch mostly, rather than being super accurate. I think it makes a good base source and then you can add effects from there, ie colours, feedback etc.

Even though there’s a useful node “Calculate Amplitudes for Frequencies” provided by Vuo, I still found it quite tricky to make a good spectrum out of it. This is probably the tenth different version I’ve trialled so far. If anyone has any tips or thoughts on how to improve it please have a go and keep me updated!

I’m not sure why but the native Vuo node I mentioned above seems to drastically overestimate the values for the lowest several bins. (Does anyone know why?) So the sound always appears to be much heavier in the sub area than it actually is. The graph also won’t fit on your screen well. So here I’ve added some maths to try and correct this problem. You’ll see one of the parameters is “correctTilt”.

The other parameters are as follows:
LineThick - if you max this out you get a messy tinsel effect. (It was always my intention to make a spectrum that could be pushed to the extreme).
YPosition - self explanatory, moves the spectrum up and down.
FrameRate - because without some control it can actually appear to run too fast.
AudioGain - self explanatory, how loud the signal is.
MixedLeftRight - this is a three option switch - 1)mix stereo channels 2) left channel only 3) right channel only.
CorrectTilt - as mentioned above, I suggest you keep this up near the maximum.
NmbrOfBins - how many points you have on the graph, this changes the appearance a lot.
ScaleXaxis - is a five option switch regarding the spacing of the x axis, linear through to exponential. Exponential looks most natural but the others can work too.
OffsetPoint1 - very trivial. just moves the left point slightly out of view.

Also be mindful that the composition is set to receive audio from the “system default”.

FreakSpex.vuo (14.6 KB)

[Kewl (Daniel Courville)]

I’m not sure why but the native Vuo node I mentioned above seems to drastically overestimate the values for the lowest several bins.

You could probably apply a high pass EQ with a very small Q before going in Calculate Amplitudes for Frequencies.

[video_piglet]

You could probably apply a high pass EQ with a very small Q before going in Calculate Amplitudes for Frequencies

I already tried that! Works hmm ok, but really you want to shelf those frequencies and not cut them. I think I got better results doing it by maths.

[MartinusMagneson (Magneson)]

In my ListTools node set there is a Scale Point List node that can be used along with a Make Points Along Line to scale the outputs of the bins in a bit more custom fashion. If you set the range of the MPAL to for instance from 0.5 to 10 and use a quadratic out curve (I think), it should halve the output from the lowest bins, and multiply the output for the highest bins by 10. You might also be able to do this with the Scale List node when I think about it.

[jmcc (Jean Marie)]

If you think there is a problem with Vuo’s handling of audio, please create a stripped-down composition that shows the problem and file a bug report. We’d need to know what other spectrum analyzer software you used for comparison that generates different results.