I don't think it's weird for a lowpass filter to go under 20Hz. They are not
restricted to audio signals.
I use them a lot to smooth control signals, or to replace line~.
(I really hate line~ to control sound amplitude or preset transition, it's way
too robotic)
cheers
c
Le 12/04/2024 à 08:01,
oh sure, but that's more like a slew or glide and you don't go down to zero
anyway :)
and if you're filtering audio, you don't want to keep inaudible stuff. All
I'm saying is that if you are soing this to fade to slience you need a DC
filter
Em sex., 12 de abr. de 2024 às 04:12, cyrille henry es
Just expand on Antoine's post, let's look at the formula of Pd's 1-pole
lowpass filter:
k = freq * 2pi / sr
y[i] = x[i] * k + y[i-1] * (1 - k)
For freq=0 this becomes:
y[i] = y[i-1]
As you can see, this would just repeat the previous output infinitely,
ignoring the input altogether. There i
Alex made a great point there!
It's that very reason why DAW plugins usually don't let you go down all
the way to zero. (Typically, they stop at 20 Hz or something.) If your
signal has components below that, you'd need a high pass filter.
On 12.04.2024 09:35, Alexandre Torres Porres wrote:
oh
0 Hz is an infinite amount of octaves below 20 Hz (10 Hz, 5 Hz, 2.5 Hz, 1.25 Hz, …).A low pass filter “normally” has a slope of a certain amount dB per octave. However, a filter with a frequency of 0 Hz doesn’t have a slope with a certain amount of dB/oct because an octave up or down from 0 Hz (by
