Hi Pd people, I need help from the masters.
I'm doing a freezing/unfreezing patch, and I'm dealing with cross fading into and out of the freeze state.
I'm actually using an oscilator bank that's being fed by sigmund~, it's actually freezing just perfectly the way I did, that's the easy part, just freeze the oscilators. Now when it unfreezes back, I need a cross fade to avoid clicks. So nothing too fancy. And I've done that alright by using delay~ to hold on a bit to the past and do the crossfade.
So the thing now is how to crossfade from the frozen signal to the slightly delayed frozen copy. This is not actually working that bad, but sometimes it is just not 100%, and you can fell a tiny difference. What to do, huh?
it's something like this
osc~
|
|
| delay~
then line~ obects for cross fading
After I freeze I go to the delayed signal, and cross fade back when I unfreeze
thanks for any help Alex
maybe the key is a gate thing like [spigot~], but that always harshly cuts the signal, anyway, even if it's not pertinent here, I wonder if we had anything smoother than that.
cheers
2011/7/7 Alexandre Torres Porres porres@gmail.com
Hi Pd people, I need help from the masters.
I'm doing a freezing/unfreezing patch, and I'm dealing with cross fading into and out of the freeze state.
I'm actually using an oscilator bank that's being fed by sigmund~, it's actually freezing just perfectly the way I did, that's the easy part, just freeze the oscilators. Now when it unfreezes back, I need a cross fade to avoid clicks. So nothing too fancy. And I've done that alright by using delay~ to hold on a bit to the past and do the crossfade.
So the thing now is how to crossfade from the frozen signal to the slightly delayed frozen copy. This is not actually working that bad, but sometimes it is just not 100%, and you can fell a tiny difference. What to do, huh?
it's something like this
osc~ |
|
| delay~then line~ obects for cross fading
After I freeze I go to the delayed signal, and cross fade back when I unfreeze
thanks for any help Alex
hmm, I should go for tab/send/receive~ right?
ok, I'll be quiet now, but please help
2011/7/7 Alexandre Torres Porres porres@gmail.com
maybe the key is a gate thing like [spigot~], but that always harshly cuts the signal, anyway, even if it's not pertinent here, I wonder if we had anything smoother than that.
cheers
2011/7/7 Alexandre Torres Porres porres@gmail.com
Hi Pd people, I need help from the masters.
I'm doing a freezing/unfreezing patch, and I'm dealing with cross fading into and out of the freeze state.
I'm actually using an oscilator bank that's being fed by sigmund~, it's actually freezing just perfectly the way I did, that's the easy part, just freeze the oscilators. Now when it unfreezes back, I need a cross fade to avoid clicks. So nothing too fancy. And I've done that alright by using delay~ to hold on a bit to the past and do the crossfade.
So the thing now is how to crossfade from the frozen signal to the slightly delayed frozen copy. This is not actually working that bad, but sometimes it is just not 100%, and you can fell a tiny difference. What to do, huh?
it's something like this
osc~ |
|
| delay~then line~ obects for cross fading
After I freeze I go to the delayed signal, and cross fade back when I unfreeze
thanks for any help Alex
It seems now it's a matter of aligning the phases, but not sure how, good night
2011/7/7 Alexandre Torres Porres porres@gmail.com
hmm, I should go for tab/send/receive~ right?
ok, I'll be quiet now, but please help
2011/7/7 Alexandre Torres Porres porres@gmail.com
maybe the key is a gate thing like [spigot~], but that always harshly cuts the signal, anyway, even if it's not pertinent here, I wonder if we had anything smoother than that.
cheers
2011/7/7 Alexandre Torres Porres porres@gmail.com
Hi Pd people, I need help from the masters.
I'm doing a freezing/unfreezing patch, and I'm dealing with cross fading into and out of the freeze state.
I'm actually using an oscilator bank that's being fed by sigmund~, it's actually freezing just perfectly the way I did, that's the easy part, just freeze the oscilators. Now when it unfreezes back, I need a cross fade to avoid clicks. So nothing too fancy. And I've done that alright by using delay~ to hold on a bit to the past and do the crossfade.
So the thing now is how to crossfade from the frozen signal to the slightly delayed frozen copy. This is not actually working that bad, but sometimes it is just not 100%, and you can fell a tiny difference. What to do, huh?
it's something like this
osc~ |
|
| delay~then line~ obects for cross fading
After I freeze I go to the delayed signal, and cross fade back when I unfreeze
thanks for any help Alex
On Fri, 8 Jul 2011, Alexandre Torres Porres wrote:
It seems now it's a matter of aligning the phases, but not sure how, good night
Phase alignment has to be done by a slight temporary pitch shift. You can shift up or shift down, but in any case, you need to shift.
If you do a plain linear cross-fade of signals (or a plain linear cross-fade of spectra, which is the same thing), it will automatically do this temporary pitch-shift, but will also do a temporary amplitude-drop at the same time.
This is because if you have two dots on a circle representing two phase alignments at the same amplitude, and you go from one to the other, you will go inside of the circle, where the amplitude is lower. The centre of the circle represents silence. In the extreme case of complete reversal of phase, the crossfade will quickly go through the silence point. But each frequency will have a different crossfade, so, overall, the amplitude drop will rarely be great, except if you tend to have few partials.
I'm thinking about phasor diagrams like http://en.wikipedia.org/wiki/Phasor , which may be considered as a use of Argand diagrams (complex numbers plane).
To keep constant amplitude, if you want to, is like rotating dots so that they keep the same amplitude (distance from centre). This is usually not easy to do, but you already have a components representation using sigmund~, so you have the opportunity to fudge the freqs a bit...
| Mathieu Bouchard ---- tél: +1.514.383.3801 ---- Villeray, Montréal, QC
wow, thanks, but you lost me :)
anyway, I thought of an easy exit but more costy, by having the double as much oscilators as copies that keep frozen.
I will try it,
Thanks again
2011/7/18 Mathieu Bouchard matju@artengine.ca
On Fri, 8 Jul 2011, Alexandre Torres Porres wrote:
It seems now it's a matter of aligning the phases, but not sure how, good
night
Phase alignment has to be done by a slight temporary pitch shift. You can shift up or shift down, but in any case, you need to shift.
If you do a plain linear cross-fade of signals (or a plain linear cross-fade of spectra, which is the same thing), it will automatically do this temporary pitch-shift, but will also do a temporary amplitude-drop at the same time.
This is because if you have two dots on a circle representing two phase alignments at the same amplitude, and you go from one to the other, you will go inside of the circle, where the amplitude is lower. The centre of the circle represents silence. In the extreme case of complete reversal of phase, the crossfade will quickly go through the silence point. But each frequency will have a different crossfade, so, overall, the amplitude drop will rarely be great, except if you tend to have few partials.
I'm thinking about phasor diagrams like http://en.wikipedia.org/wiki/** Phasor http://en.wikipedia.org/wiki/Phasor , which may be considered as a use of Argand diagrams (complex numbers plane).
To keep constant amplitude, if you want to, is like rotating dots so that they keep the same amplitude (distance from centre). This is usually not easy to do, but you already have a components representation using sigmund~, so you have the opportunity to fudge the freqs a bit...
______________________________**______________________________** ___________ | Mathieu Bouchard ---- tél: +1.514.383.3801 ---- Villeray, Montréal, QC
On Tue, 19 Jul 2011, Alexandre Torres Porres wrote:
wow, thanks, but you lost me :)
:(
anyway, I thought of an easy exit but more costy, by having the double as much oscilators as copies that keep frozen.
What does that fix ?
If you have two sinewaves at the same freq, they will often cancel each other. It doesn't matter how you produce the waves, it's all about the phases.
To understand that, there's a trigonometric identity, and there's a diagram for visualising that trigonometric identity.
| Mathieu Bouchard ---- tél: +1.514.383.3801 ---- Villeray, Montréal, QC