The craziest post ever!

[tulamide]

Yep, this might be it. The craziest post, I have ever created.

It started with me not falling asleep. After some time I started my PC and randomly watched short videos on Youtube. Then I saw a video taken from a show probably around the early 80s. The curiosity show. And it presented the "mysterious isochronous curve". Of course I knew about the curve, but not the name. And refreshing on the properties of such a curve, I immediately started thinking of applications in the DSP world. After over an hour my head is almost sweating blood, but still creativity didn't hit me.

Can you think of something?

https://youtu.be/eBc827pwKf0

[ChrisHooker]

Perhaps:
- Oscillator waveforms (peaking, sinusoidal-ish, shark-fin)
- MIDI velocity curves
- Compression gain timing-curves
- Compression key-filtering (like a weighting curve)
- Distortion characteristic

[Spogg]

Fascinating!

I never knew about this and the demo is so counterintuitive.

It reminds me of dropping a feather and a stone on the moon at the same time. They both hit the ground simultaneously, and it kinda feels strange to see it.

In the case of the curve I can see that the acceleration, due to the shape, is higher the further away the ball is, but it has further to travel. Amazing that the curve can be created in the way shown too.

Cheers

Spogg

[adamszabo]

Here is a modern take on the subject they are also known as Cycloids. They build some tests with Adam from the Mythbusters.

https://www.youtube.com/watch?v=skvnj67YGmw

[tulamide]

I love Adam Savage, since the early days of the first Mythbusters season. His own Youtube channel is full of amazing builds.

But what fascinates me about the curve is that it shares properties of lerp!

Lerp = linear interpolation from a to b at t, where t is a percentage.

So, if I have a distance with a goal line g, and do lerp repeatedly from two points p1 and p2, incrementing with the same values for t, both will arrive at g exactly at the same time. That property is used over and over again in graphics, for example so that a certain action always takes the same amount of time, no matter the distance. But the result of lerping always is a straight line.

The isochrone is basically lerp but on a curve! And you have two axes (distance and gravity [g =basically constant velocity]), whereas lerp is one-dimensional and has to be applied two times (once per axis).

That's pretty amazing and I hope that their is an application for it in our DSP world!