The Filter- The ARP 2600 Filter demonstrated with an Oscilloscope

[@station2station544]

Old video but great. We subtractive folks all know the ranking of the waveforms harmonic content (saw, pulse, square, etc) that sound good when filtered to varying degrees, but this explains exactly why the SINE is so immune to being filtered. Thank you.

[@mohmad2822]

How do I display the wave as an Oscilloscope in this filter for me to edit?

[@mohmad2822]

Do I have to in sound engineering convert zigzag waves into sine waves? *because the sine wave is called a pure wave!*

[@AdamBorseti]

Isn't the sine wave more of a triangle here? I know analog VCOs don't produce perfect shapes, but...... Anyway... I love your videos Marc!

[@moogfoundation]

+Adam Borseti It certainly looks pretty triangular! But as the filter is closed, you can see that the shape doesn't change. The triangle wave has some higher frequencies in it that give it its shape, and that point is attenuated pretty quickly when closing the filter.

[@AdamBorseti]

Yeah, I'm used to ~~~~~ not /\/\/\/\/\

[@Roderick_Legato]

You are right Adam, that's not a sine wave. It's a triangle wave, possibly followed by something like a soft clipper that is rounding off the peaks (low pass filtering a triangle would not produce the straight rise and fall lines shown here, they will have begun to curve). Also, as the filter is closed, the shape DOES change. Using the trigger control on the 'scope would have made this effect much easier to see, but it's possible to see the waveforms clearly by just pausing the video. At about 0:48 you can clearly hear the harmonics go away as the triangle is converted to a sine wave. If this had been a sine wave to begin with, lowering the cutoff frequency would only have produced an amplitude change.