My name is Siebe, I'm a MT-student from the Netherlands.
Hi, Siebe! Welcome on board, IMHO there is a great shortage of Dutch ChucKists so it's good to see you here.
My question is, am I doing it right? Since both examples are pretty much the same, my guess is that both should work.
Yes, well, they are indeed quite close when we look at the text in the files, but one of them deals with a array of floats while another deals with complex numbers. As FFT expects to deal with complex numbers it's not so surprising that the one using floats doesn't work.
When you order french fries and I instead serve you fried potato slices you'll most likely be able to deal with that. Sadly bits of ChucK code aren't so flexible and will complain if they don't get what they expected.
The one exception is when a float is expected and we "serve" a int, in that case ChucK will imagine the infinite series of zero's aftter the decimal dot is actually there (behind the scenes it actually casts them to a float). To ChucK a complex number is quite different from a float and ChucK is unwilling to "imagine" there is a second number there.
In a way ChucK is quite picky (which can be anoying) and will force you to clearly speciffy what you mean (which can often be a good thing).