Em sáb., 13 de abr. de 2024 às 06:30, Peter P.
escreveu:
> Looking at [vcf~]'s help patch closer, I read that the filter's real and
> complex outputs may be combined to allow for other filtering possibilies
> than band-pass and low-pass. Does anyone have a quick example of such a
> combination?
Hi,
On 13.04.24 10:57, Peter P. wrote:
Thank you Christof,
your equation helped me a lot, and now I see why some DC component will
be circulating the filter forever.
Thank you Edwin,
explaining that "0 Hz is an infinite amount of octaves below 20 Hz" made
me understand that a cutoff at 0Hz
Thank you Christof,
your equation helped me a lot, and now I see why some DC component will
be circulating the filter forever.
Thank you Edwin,
explaining that "0 Hz is an infinite amount of octaves below 20 Hz" made
me understand that a cutoff at 0Hz will not reduce DC by -3dB.
Looking at
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
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:
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
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
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
and you got a strong DC component over there :)
anyway, it also seems weird to have a lowpass or a bandpass going as low as
in the 20hz range. If you wanna do it just so it fades out to silence, you
need a DC filter, something like a [hip~ 5] object, so when the lowpass,
bandpass gets there, then
Well, let's simplify a bit, forget all the filter complexity (Q, slope,
definition of the cutoff frequency...).
Let's just say that the output of a lowpass filter cannot move faster than
the cutoff frequency: a 1Hz filter output cannot move faster than 1Hz (so
it can't go back and forth in less
* Antoine Rousseau [2024-04-11 13:40]:
> That doesn't seem incorrect to me; after all, a lowpass filter at 0Hz
> implies that its output is constant (any change would involve frequencies >
> 0Hz).
Thanks Antoine,
Why does a lowpass filter, that has a cutoff frequency of 0Hz imply that
it's
That doesn't seem incorrect to me; after all, a lowpass filter at 0Hz
implies that its output is constant (any change would involve frequencies >
0Hz).
Antoine
Le jeu. 11 avr. 2024 à 13:08, Peter P. a écrit :
> * Alexandre Torres Porres [2024-04-10 22:19]:
> > the problem is your input, with
* Alexandre Torres Porres [2024-04-10 22:19]:
> the problem is your input, with a DC component (0 hz). This doesn't seem to
> happen with [osc~] and seems like normal behaviour and not something to be
> documented
I see, phasor~'s waveform is not symmetric around 0, good point. But why
will
the problem is your input, with a DC component (0 hz). This doesn't seem to
happen with [osc~] and seems like normal behaviour and not something to be
documented
cheers
Em qua., 10 de abr. de 2024 às 11:56, Peter P.
escreveu:
> Howdy list,
>
> just discovered, that [vcf~] produces output after
Howdy list,
just discovered, that [vcf~] produces output after its input has decayed
for a cutoff frequency of 0Hz, but not for values higher 0.
A minimal working example is attached. Is this behavior known? Could it
be mentioned in the help patch maybe?
cheersz, P
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