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resonance...
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orik
IsraTrance Junior Member
Started Topics :
45
Posts :
317
Posted : Dec 2, 2004 16:54
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synthwize...how does ressonance exactly works...i know its some sort of filtering
of the bandwidth of a speciefic area in your
sound...but how exactly.... |
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AvS
Started Topics :
9
Posts :
464
Posted : Dec 2, 2004 18:30
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Resonance is a boost around the cutoff frequency. The effect is a kind of a ringing/wet/screaming sound.
I think it is done by routing the frequncies around the cutoff frequency to the input if the filter so you get feedback. This explains why some filters selfoscillate (a feedback loop). |
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Colin OOOD
Moderator
Started Topics :
95
Posts :
5380
Posted : Dec 2, 2004 23:38
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Mike A
Subra
Started Topics :
185
Posts :
3954
Posted : Dec 3, 2004 00:03
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Get the Blue Filter vst, it shows a graph and you can see the parameters change it.
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UnderTow
Started Topics :
9
Posts :
1448
Posted : Dec 3, 2004 01:04
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Colin, thats true for analogue filters AFAIK but I'm not sure that is always the case with digital filters.
UnderTow |
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AvS
Started Topics :
9
Posts :
464
Posted : Dec 3, 2004 11:57
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Quote:
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On 2004-12-02 23:38, Colin OOOD wrote:
As far as I know it's done by routing the entire output of the filter back to the input, not just certain frequencies.
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Ok. But why is it only the freqs around the cutoff frequency that are boosted then? |
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karmaceuticals
Started Topics :
0
Posts :
29
Posted : Dec 3, 2004 13:54
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what is resonance?
http://en.wikipedia.org/wiki/Resonant_frequency
my guess is that AvS is right, it's kinda like the resonance you got in an Instrument such as a guitar, but you can set where the resonance is (cutoff) and wich strength it has.
well, it's still only a guess 
greets |
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ZilDoggo
Started Topics :
4
Posts :
663
Posted : Dec 3, 2004 17:47
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hehe., yeah.,
you are right in this order:
undertow - makes total sense
Mike A - almost right (i think )
AvS - slightly right
ok so let me explain (to the point that i'm not right anymore )
(analog) filters are basically phase shifting networks.,
they shift phase depending on frequency.,
so, in case of a LPF, the network starts shifting the phase of the signal (even before the cutoff point) from 0 degrees to 180 (or was it -180) degrees.,
the bandwidth over which this phase change occurs determines the filters steepness., (ie. 6,12,18,24db/oct)
when this phased signal is combined with the original it will phase out some portion of the spectrum.,
resonance is achived INSIDE this phase shifting network AFAIK., not simply connecting the output to the input but a real resonance of the electronics that make up the filter.,
resonance is not simply a sinus that looks as if it is added at the cutoff freq. , its the result of the filter 'exciting' itself., in ther words, the feedback loop actually interacts with how the filter works!
if you change the filter cutoff the resonance will move along.,
this is because the phasing characteristics come from a form of (internal) feedback too!!.,
so a change to the phasing network (i.e. changing the cutoff point) also means that the resonance characteristics change,.,
so resonance is just a portion of how analog filters physically work., .,
well, i think there was this thing where you can take the output of the filter and insert in somewhere inside the network., but that is a special design thing AFAIK., you can smack me if i'm wrong about this.,
and i guess this is where my knowledge ends
and about digital filters., these can work in all sorts of ways,
i've seen filters that dont have any resonance by themselfs and there is a sine wave added after the filtering on the right frequency., so in that case resonance is just a trick.,
but i mainly want to point out the phasing stuff in analog filters cause it's realy cool stuff
anyway., i'm brabbling too much
greets.,
aka., |
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