Hi, are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass?
thanks
Based on your posts in this group, you definitely know more about filters than I do, so I don't really have an answer to this question - but I'm wondering if by "resonant" filter you mean the same thing as "resonator" filter?
I saw something interesting earlier today about using resonator filters as control sources for FM synthesis: http://tai-studio.org/index.php/projects/sound-programming/complexres/
The paper that is linked in the article has some details on the mathematical implementation of the filter, but that's mostly mumbo-jumbo to me.
On Mon, Jan 12, 2015 at 4:24 PM, Alexandre Torres Porres porres@gmail.com wrote:
Hi, are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass?
thanks
Pd-list@lists.iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
Nice I give an impression to be an expert, but filters is just something I've actually recently started studying :)
I'm wondering if by "resonant" filter you mean the same thing as "resonator" filter?
Now you got me... good question, and I'm not sure, haha. The link looks nice btw, will definitely check it. Thanks.
So now I'm even more confused. Is "resonant filter" and "resonator" two different concepts? Maybe I'm having trouble with the english nomenclature and everything.
To be honest and more detailed about the issues I'm encountering, I ask this based on another topic I was discussing with Julius Smith in the Supercollider list, but it went dead and I got no replies. In it I was asking if the object "Resonz" should really be called a "Resonant filter", because it was just a bandpass filter in my opinion. Then Julius was mentioning how "*A resonator is a special case of a passband filter having a nearly zero-width passband.*"
I see he used the term "resonator" and not "Resonant Filter" (as Resonz is described). So yeah, now I'm more confused... is resonator the same as resonant or what?
But anyway, we can bring the discussion into the Pd world, and talk about the [reson~] object, as I will do later on.
I was googling and saw how the term resonant filter could be used to describe a regular bandpass filter. And how the bandpass' center frequency could also be called "resonant frequency". So they might be used in the same way... (accurately or not).
Now here is my opinion. Just like a resonant low pass filter (the [lores~] object in Pd), the concept of resonance in a filter relates to how it adds gain around the resonant frequency.
In the Audio-EQ-Cookbook (link: http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt ) that presents formulas for biquad coeficients you have two different bandpass filters, lets call them BPF1 and BPF2. So, BPF2 has "constant 0 dB peak gain", meaning it doesn't affect anything arounf the center frequency. Now BPF1 says it has "constant skirt gain, peak gain = Q", meaning that the Q or bandwidth controls the gain of the filter. I consider BPF2 to be a regular bandpass filter, whereas BPF1, which adds gain for narrower bandwidths, seems to be a "resonant" one... (which makes me think Resonz shouldn't be described as resonant filter, as it's just a bandpass, or "BPF2").
Oh, there's another term around, the "ringing" filter, which seems to be another term for resonant filter. In SuperCollider they have Ringz, which was supposed to be the same as Resonz object (or a resonant filter for that matter), but they are different like the two different kinds of bandpass in the EQ Cookbook (Ringz = BPF1 / Resonz = BPF2).
Coming into the Pd world we can talk about the [reson~] object. As the name implies, it is a resonant filter. But the helpfile says it is a "Bandpass filter" (damn). Funny enough, in Max, the [reson~] object is said to be indded a *Resonant Bandpass Filter*. So maybe we should update [reson~]'s help file in Pd... But the deal is: [reson~] is actually a bandpass like BFP2 or Resonz, but it has a separate parameter for the gain. Meaning it works basically as a bandpass filter, where changing the Q doesn't affect the gain. But you can also give it a boost or a cut with the gain parameter. By giving it a boost it would behave in a way that I'm considering to be an actual "resonant" filter.
Now let me go ahead and share a patch that I'm writing for my computer music classes. It's about several filters that can be obtained with biquad. So I present Pd's vanilla filters such as [lop~], [hip~] and [bp~]. I also present externals like [lores~] and [reson~] and I do present all the filters from the Audio Eq Cookbook as well. It's in portuguese, and part of a big series of examples, but what the hell...
By the way, I was also able to implement Resonz and Ringz as [biquad~] in Pd, but I don't have it on this example (but to hell with supercollider already, hehe).
So there you can check the behaviour and differences that I've pointed. For [reson~], I have two separate parameters, one is for "Q", and the other one, which is originally "gain", I'm calling the "resonance" parameter. Much like the resonance parameter in [lores~]...
As for the Cookbook filters, BPF2 is what I'm calling a regular "bandpass", and it has a parameter of "Q". As for BPF1, I'm calling it a "resonant filter", and it has a parameter of "resonance" instead of "Q" (but the idea is that more Q gives more gain/resonance).
I hope I'm clear in the midst of so much detail and information. It's just a stupid doubt on the nomenclature of filters, but this kind of issue can be quite a pain in the ass, and the subject of many confusions.
So, in short, I still keep my original question: Are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass? Moreover, what about a resonator? Is my assumption on how to call one a bandpass and a resonant correct or it doesn't have anything to do with the official literature? And how about what Julius Smith had to say?
Cheers
2015-01-12 20:03 GMT-02:00 Brian Fay ovaltinevortex@gmail.com:
Based on your posts in this group, you definitely know more about filters than I do, so I don't really have an answer to this question - but I'm wondering if by "resonant" filter you mean the same thing as "resonator" filter?
I saw something interesting earlier today about using resonator filters as control sources for FM synthesis: http://tai-studio.org/index.php/projects/sound-programming/complexres/
The paper that is linked in the article has some details on the mathematical implementation of the filter, but that's mostly mumbo-jumbo to me.
On Mon, Jan 12, 2015 at 4:24 PM, Alexandre Torres Porres <porres@gmail.com
wrote:
Hi, are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass?
thanks
Pd-list@lists.iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
I was looking at circuit diagrams for analog synthesizers recently and noticed that the "resonance" control is nothing more than feeding some fraction of the output back to the input. With more feedback oscillation occurs at the cutoff frequency for any type of filter, highpass, bandpass or lowpass.
Martin
On Mon, Jan 12, 2015 at 9:09 PM, Alexandre Torres Porres porres@gmail.com wrote:
Nice I give an impression to be an expert, but filters is just something I've actually recently started studying :)
I'm wondering if by "resonant" filter you mean the same thing as "resonator" filter?
Now you got me... good question, and I'm not sure, haha. The link looks nice btw, will definitely check it. Thanks.
So now I'm even more confused. Is "resonant filter" and "resonator" two different concepts? Maybe I'm having trouble with the english nomenclature and everything.
To be honest and more detailed about the issues I'm encountering, I ask this based on another topic I was discussing with Julius Smith in the Supercollider list, but it went dead and I got no replies. In it I was asking if the object "Resonz" should really be called a "Resonant filter", because it was just a bandpass filter in my opinion. Then Julius was mentioning how "*A resonator is a special case of a passband filter having a nearly zero-width passband.*"
I see he used the term "resonator" and not "Resonant Filter" (as Resonz is described). So yeah, now I'm more confused... is resonator the same as resonant or what?
But anyway, we can bring the discussion into the Pd world, and talk about the [reson~] object, as I will do later on.
I was googling and saw how the term resonant filter could be used to describe a regular bandpass filter. And how the bandpass' center frequency could also be called "resonant frequency". So they might be used in the same way... (accurately or not).
Now here is my opinion. Just like a resonant low pass filter (the [lores~] object in Pd), the concept of resonance in a filter relates to how it adds gain around the resonant frequency.
In the Audio-EQ-Cookbook (link: http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt ) that presents formulas for biquad coeficients you have two different bandpass filters, lets call them BPF1 and BPF2. So, BPF2 has "constant 0 dB peak gain", meaning it doesn't affect anything arounf the center frequency. Now BPF1 says it has "constant skirt gain, peak gain = Q", meaning that the Q or bandwidth controls the gain of the filter. I consider BPF2 to be a regular bandpass filter, whereas BPF1, which adds gain for narrower bandwidths, seems to be a "resonant" one... (which makes me think Resonz shouldn't be described as resonant filter, as it's just a bandpass, or "BPF2").
Oh, there's another term around, the "ringing" filter, which seems to be another term for resonant filter. In SuperCollider they have Ringz, which was supposed to be the same as Resonz object (or a resonant filter for that matter), but they are different like the two different kinds of bandpass in the EQ Cookbook (Ringz = BPF1 / Resonz = BPF2).
Coming into the Pd world we can talk about the [reson~] object. As the name implies, it is a resonant filter. But the helpfile says it is a "Bandpass filter" (damn). Funny enough, in Max, the [reson~] object is said to be indded a *Resonant Bandpass Filter*. So maybe we should update [reson~]'s help file in Pd... But the deal is: [reson~] is actually a bandpass like BFP2 or Resonz, but it has a separate parameter for the gain. Meaning it works basically as a bandpass filter, where changing the Q doesn't affect the gain. But you can also give it a boost or a cut with the gain parameter. By giving it a boost it would behave in a way that I'm considering to be an actual "resonant" filter.
Now let me go ahead and share a patch that I'm writing for my computer music classes. It's about several filters that can be obtained with biquad. So I present Pd's vanilla filters such as [lop~], [hip~] and [bp~]. I also present externals like [lores~] and [reson~] and I do present all the filters from the Audio Eq Cookbook as well. It's in portuguese, and part of a big series of examples, but what the hell...
By the way, I was also able to implement Resonz and Ringz as [biquad~] in Pd, but I don't have it on this example (but to hell with supercollider already, hehe).
So there you can check the behaviour and differences that I've pointed. For [reson~], I have two separate parameters, one is for "Q", and the other one, which is originally "gain", I'm calling the "resonance" parameter. Much like the resonance parameter in [lores~]...
As for the Cookbook filters, BPF2 is what I'm calling a regular "bandpass", and it has a parameter of "Q". As for BPF1, I'm calling it a "resonant filter", and it has a parameter of "resonance" instead of "Q" (but the idea is that more Q gives more gain/resonance).
I hope I'm clear in the midst of so much detail and information. It's just a stupid doubt on the nomenclature of filters, but this kind of issue can be quite a pain in the ass, and the subject of many confusions.
So, in short, I still keep my original question: Are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass? Moreover, what about a resonator? Is my assumption on how to call one a bandpass and a resonant correct or it doesn't have anything to do with the official literature? And how about what Julius Smith had to say?
Cheers
2015-01-12 20:03 GMT-02:00 Brian Fay ovaltinevortex@gmail.com:
Based on your posts in this group, you definitely know more about filters
than I do, so I don't really have an answer to this question - but I'm wondering if by "resonant" filter you mean the same thing as "resonator" filter?
I saw something interesting earlier today about using resonator filters as control sources for FM synthesis: http://tai-studio.org/index.php/projects/sound-programming/complexres/
The paper that is linked in the article has some details on the mathematical implementation of the filter, but that's mostly mumbo-jumbo to me.
On Mon, Jan 12, 2015 at 4:24 PM, Alexandre Torres Porres < porres@gmail.com> wrote:
Hi, are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass?
thanks
Pd-list@lists.iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
Pd-list@lists.iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
I'm pending to say that there is no real distinction between "Resonant filter" and a "resonator", and a "bandpass" can be implicitly thought of as a resonator. Here's what I also found in Julius' website
https://ccrma.stanford.edu/~jos/filters/First_Order_Complex_Resonators.html
Pass the mouse cursor over the "Resonator" over the title "First-Order Complex Resonators https://ccrma.stanford.edu/~jos/filters/Two_Pole.html" to see the popup (also attached).
cheers
2015-01-13 1:20 GMT-02:00 Martin Peach chakekatzil@gmail.com:
I was looking at circuit diagrams for analog synthesizers recently and noticed that the "resonance" control is nothing more than feeding some fraction of the output back to the input. With more feedback oscillation occurs at the cutoff frequency for any type of filter, highpass, bandpass or lowpass.
Martin
On Mon, Jan 12, 2015 at 9:09 PM, Alexandre Torres Porres <porres@gmail.com
wrote:
Nice I give an impression to be an expert, but filters is just something I've actually recently started studying :)
I'm wondering if by "resonant" filter you mean the same thing as "resonator" filter?
Now you got me... good question, and I'm not sure, haha. The link looks nice btw, will definitely check it. Thanks.
So now I'm even more confused. Is "resonant filter" and "resonator" two different concepts? Maybe I'm having trouble with the english nomenclature and everything.
To be honest and more detailed about the issues I'm encountering, I ask this based on another topic I was discussing with Julius Smith in the Supercollider list, but it went dead and I got no replies. In it I was asking if the object "Resonz" should really be called a "Resonant filter", because it was just a bandpass filter in my opinion. Then Julius was mentioning how "*A resonator is a special case of a passband filter having a nearly zero-width passband.*"
I see he used the term "resonator" and not "Resonant Filter" (as Resonz is described). So yeah, now I'm more confused... is resonator the same as resonant or what?
But anyway, we can bring the discussion into the Pd world, and talk about the [reson~] object, as I will do later on.
I was googling and saw how the term resonant filter could be used to describe a regular bandpass filter. And how the bandpass' center frequency could also be called "resonant frequency". So they might be used in the same way... (accurately or not).
Now here is my opinion. Just like a resonant low pass filter (the [lores~] object in Pd), the concept of resonance in a filter relates to how it adds gain around the resonant frequency.
In the Audio-EQ-Cookbook (link: http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt ) that presents formulas for biquad coeficients you have two different bandpass filters, lets call them BPF1 and BPF2. So, BPF2 has "constant 0 dB peak gain", meaning it doesn't affect anything arounf the center frequency. Now BPF1 says it has "constant skirt gain, peak gain = Q", meaning that the Q or bandwidth controls the gain of the filter. I consider BPF2 to be a regular bandpass filter, whereas BPF1, which adds gain for narrower bandwidths, seems to be a "resonant" one... (which makes me think Resonz shouldn't be described as resonant filter, as it's just a bandpass, or "BPF2").
Oh, there's another term around, the "ringing" filter, which seems to be another term for resonant filter. In SuperCollider they have Ringz, which was supposed to be the same as Resonz object (or a resonant filter for that matter), but they are different like the two different kinds of bandpass in the EQ Cookbook (Ringz = BPF1 / Resonz = BPF2).
Coming into the Pd world we can talk about the [reson~] object. As the name implies, it is a resonant filter. But the helpfile says it is a "Bandpass filter" (damn). Funny enough, in Max, the [reson~] object is said to be indded a *Resonant Bandpass Filter*. So maybe we should update [reson~]'s help file in Pd... But the deal is: [reson~] is actually a bandpass like BFP2 or Resonz, but it has a separate parameter for the gain. Meaning it works basically as a bandpass filter, where changing the Q doesn't affect the gain. But you can also give it a boost or a cut with the gain parameter. By giving it a boost it would behave in a way that I'm considering to be an actual "resonant" filter.
Now let me go ahead and share a patch that I'm writing for my computer music classes. It's about several filters that can be obtained with biquad. So I present Pd's vanilla filters such as [lop~], [hip~] and [bp~]. I also present externals like [lores~] and [reson~] and I do present all the filters from the Audio Eq Cookbook as well. It's in portuguese, and part of a big series of examples, but what the hell...
By the way, I was also able to implement Resonz and Ringz as [biquad~] in Pd, but I don't have it on this example (but to hell with supercollider already, hehe).
So there you can check the behaviour and differences that I've pointed. For [reson~], I have two separate parameters, one is for "Q", and the other one, which is originally "gain", I'm calling the "resonance" parameter. Much like the resonance parameter in [lores~]...
As for the Cookbook filters, BPF2 is what I'm calling a regular "bandpass", and it has a parameter of "Q". As for BPF1, I'm calling it a "resonant filter", and it has a parameter of "resonance" instead of "Q" (but the idea is that more Q gives more gain/resonance).
I hope I'm clear in the midst of so much detail and information. It's just a stupid doubt on the nomenclature of filters, but this kind of issue can be quite a pain in the ass, and the subject of many confusions.
So, in short, I still keep my original question: Are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass? Moreover, what about a resonator? Is my assumption on how to call one a bandpass and a resonant correct or it doesn't have anything to do with the official literature? And how about what Julius Smith had to say?
Cheers
2015-01-12 20:03 GMT-02:00 Brian Fay ovaltinevortex@gmail.com:
Based on your posts in this group, you definitely know more about filters
than I do, so I don't really have an answer to this question - but I'm wondering if by "resonant" filter you mean the same thing as "resonator" filter?
I saw something interesting earlier today about using resonator filters as control sources for FM synthesis: http://tai-studio.org/index.php/projects/sound-programming/complexres/
The paper that is linked in the article has some details on the mathematical implementation of the filter, but that's mostly mumbo-jumbo to me.
On Mon, Jan 12, 2015 at 4:24 PM, Alexandre Torres Porres < porres@gmail.com> wrote:
Hi, are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass?
thanks
Pd-list@lists.iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
Pd-list@lists.iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
It sounds like the Resonz UGen in supercollider is exactly what Julius Smith is talking about in that description of the two-pole filter.
But then there's the other supercollider filter UGens with "resonant" in the name, which seem more like what Martin was describing - RLPF (resonant low-pass filter) for example is a low-pass filter where you can adjust the resonance near the cutoff. I haven't played with this too much myself, but I'm guessing with the right Q value you could drive this to self-oscillation?
Ultimately I think "resonant" is a general descriptive term for filters, that shouldn't be interpreted as a detail of implementation.
On Tue, Jan 13, 2015 at 9:28 AM, Alexandre Torres Porres porres@gmail.com wrote:
I'm pending to say that there is no real distinction between "Resonant filter" and a "resonator", and a "bandpass" can be implicitly thought of as a resonator. Here's what I also found in Julius' website
https://ccrma.stanford.edu/~jos/filters/First_Order_Complex_Resonators.html
Pass the mouse cursor over the "Resonator" over the title "First-Order Complex Resonators https://ccrma.stanford.edu/~jos/filters/Two_Pole.html" to see the popup (also attached).
cheers
2015-01-13 1:20 GMT-02:00 Martin Peach chakekatzil@gmail.com:
I was looking at circuit diagrams for analog synthesizers recently and
noticed that the "resonance" control is nothing more than feeding some fraction of the output back to the input. With more feedback oscillation occurs at the cutoff frequency for any type of filter, highpass, bandpass or lowpass.
Martin
On Mon, Jan 12, 2015 at 9:09 PM, Alexandre Torres Porres < porres@gmail.com> wrote:
Nice I give an impression to be an expert, but filters is just something I've actually recently started studying :)
I'm wondering if by "resonant" filter you mean the same thing as "resonator" filter?
Now you got me... good question, and I'm not sure, haha. The link looks nice btw, will definitely check it. Thanks.
So now I'm even more confused. Is "resonant filter" and "resonator" two different concepts? Maybe I'm having trouble with the english nomenclature and everything.
To be honest and more detailed about the issues I'm encountering, I ask this based on another topic I was discussing with Julius Smith in the Supercollider list, but it went dead and I got no replies. In it I was asking if the object "Resonz" should really be called a "Resonant filter", because it was just a bandpass filter in my opinion. Then Julius was mentioning how "*A resonator is a special case of a passband filter having a nearly zero-width passband.*"
I see he used the term "resonator" and not "Resonant Filter" (as Resonz is described). So yeah, now I'm more confused... is resonator the same as resonant or what?
But anyway, we can bring the discussion into the Pd world, and talk about the [reson~] object, as I will do later on.
I was googling and saw how the term resonant filter could be used to describe a regular bandpass filter. And how the bandpass' center frequency could also be called "resonant frequency". So they might be used in the same way... (accurately or not).
Now here is my opinion. Just like a resonant low pass filter (the [lores~] object in Pd), the concept of resonance in a filter relates to how it adds gain around the resonant frequency.
In the Audio-EQ-Cookbook (link: http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt ) that presents formulas for biquad coeficients you have two different bandpass filters, lets call them BPF1 and BPF2. So, BPF2 has "constant 0 dB peak gain", meaning it doesn't affect anything arounf the center frequency. Now BPF1 says it has "constant skirt gain, peak gain = Q", meaning that the Q or bandwidth controls the gain of the filter. I consider BPF2 to be a regular bandpass filter, whereas BPF1, which adds gain for narrower bandwidths, seems to be a "resonant" one... (which makes me think Resonz shouldn't be described as resonant filter, as it's just a bandpass, or "BPF2").
Oh, there's another term around, the "ringing" filter, which seems to be another term for resonant filter. In SuperCollider they have Ringz, which was supposed to be the same as Resonz object (or a resonant filter for that matter), but they are different like the two different kinds of bandpass in the EQ Cookbook (Ringz = BPF1 / Resonz = BPF2).
Coming into the Pd world we can talk about the [reson~] object. As the name implies, it is a resonant filter. But the helpfile says it is a "Bandpass filter" (damn). Funny enough, in Max, the [reson~] object is said to be indded a *Resonant Bandpass Filter*. So maybe we should update [reson~]'s help file in Pd... But the deal is: [reson~] is actually a bandpass like BFP2 or Resonz, but it has a separate parameter for the gain. Meaning it works basically as a bandpass filter, where changing the Q doesn't affect the gain. But you can also give it a boost or a cut with the gain parameter. By giving it a boost it would behave in a way that I'm considering to be an actual "resonant" filter.
Now let me go ahead and share a patch that I'm writing for my computer music classes. It's about several filters that can be obtained with biquad. So I present Pd's vanilla filters such as [lop~], [hip~] and [bp~]. I also present externals like [lores~] and [reson~] and I do present all the filters from the Audio Eq Cookbook as well. It's in portuguese, and part of a big series of examples, but what the hell...
By the way, I was also able to implement Resonz and Ringz as [biquad~] in Pd, but I don't have it on this example (but to hell with supercollider already, hehe).
So there you can check the behaviour and differences that I've pointed. For [reson~], I have two separate parameters, one is for "Q", and the other one, which is originally "gain", I'm calling the "resonance" parameter. Much like the resonance parameter in [lores~]...
As for the Cookbook filters, BPF2 is what I'm calling a regular "bandpass", and it has a parameter of "Q". As for BPF1, I'm calling it a "resonant filter", and it has a parameter of "resonance" instead of "Q" (but the idea is that more Q gives more gain/resonance).
I hope I'm clear in the midst of so much detail and information. It's just a stupid doubt on the nomenclature of filters, but this kind of issue can be quite a pain in the ass, and the subject of many confusions.
So, in short, I still keep my original question: Are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass? Moreover, what about a resonator? Is my assumption on how to call one a bandpass and a resonant correct or it doesn't have anything to do with the official literature? And how about what Julius Smith had to say?
Cheers
2015-01-12 20:03 GMT-02:00 Brian Fay ovaltinevortex@gmail.com:
Based on your posts in this group, you definitely know more about
filters than I do, so I don't really have an answer to this question - but I'm wondering if by "resonant" filter you mean the same thing as "resonator" filter?
I saw something interesting earlier today about using resonator filters as control sources for FM synthesis: http://tai-studio.org/index.php/projects/sound-programming/complexres/
The paper that is linked in the article has some details on the mathematical implementation of the filter, but that's mostly mumbo-jumbo to me.
On Mon, Jan 12, 2015 at 4:24 PM, Alexandre Torres Porres < porres@gmail.com> wrote:
Hi, are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass?
thanks
Pd-list@lists.iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
Pd-list@lists.iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
"*Ultimately I think "resonant" is a general descriptive term for filters, that shouldn't be interpreted as a detail of implementation.*"
I guess you have a point there, and I was also driving to this conclusion.
"*It sounds like the Resonz UGen in supercollider is exactly what Julius Smith is talking about in that description of the two-pole filter.*"
Actually, the Resonz UGen is a Two Pole / Two Zero filter, which is very more closely related to [cyclone/reson~].
A Two-Pole only filter (no zeros) like the one Julius is describing is actually what the [bp~] object is!
"*But then there's the other supercollider filter UGens with "resonant" in the name, which seem more like what Martin was describing - RLPF (resonant low-pass filter) for example is a low-pass filter where you can adjust the resonance near the cutoff.* "
Yep, and this is also much like the [cyclone/lores~] object in Pd. Check that patch I sent for more detailed info on these filters.
I've always assumed that a filter, in order to be called a "resonant filter" or a "resonator" - being it a low pass, a high pass or a band pass -, needed to boost/add gain to a particular cutoff frequency (in the case of lowpass and highpas - which is the case for [lores~] or RLPF) or add gain to some center frequency (in the case of a bandpass) - which is also called "resonant frequency".
The quote from Julius in that link - where he says "*A resonator is a recursive filter that boosts signal amplitude at a particular frequency*" - is in line with my assumption.
But the concept of resonance in physics, in its utmost purity according to wikipedia, is that it "is the tendency of a system to oscillate with greater amplitude at some frequencies than at others". Meaning that it doesn't really have to add gain to something, but only favor a frequency amongst others... In this context, a bandpass - in general - is a "resonator"...
But it'd be cool if I could find a definitive word about this in the filter literature!
Cheers
2015-01-13 13:16 GMT-02:00 Brian Fay ovaltinevortex@gmail.com:
It sounds like the Resonz UGen in supercollider is exactly what Julius Smith is talking about in that description of the two-pole filter.
But then there's the other supercollider filter UGens with "resonant" in the name, which seem more like what Martin was describing - RLPF (resonant low-pass filter) for example is a low-pass filter where you can adjust the resonance near the cutoff. I haven't played with this too much myself, but I'm guessing with the right Q value you could drive this to self-oscillation?
Ultimately I think "resonant" is a general descriptive term for filters, that shouldn't be interpreted as a detail of implementation.
On Tue, Jan 13, 2015 at 9:28 AM, Alexandre Torres Porres <porres@gmail.com
wrote:
I'm pending to say that there is no real distinction between "Resonant filter" and a "resonator", and a "bandpass" can be implicitly thought of as a resonator. Here's what I also found in Julius' website
https://ccrma.stanford.edu/~jos/filters/First_Order_Complex_Resonators.html
Pass the mouse cursor over the "Resonator" over the title "First-Order Complex Resonators https://ccrma.stanford.edu/~jos/filters/Two_Pole.html" to see the popup (also attached).
cheers
2015-01-13 1:20 GMT-02:00 Martin Peach chakekatzil@gmail.com:
I was looking at circuit diagrams for analog synthesizers recently and
noticed that the "resonance" control is nothing more than feeding some fraction of the output back to the input. With more feedback oscillation occurs at the cutoff frequency for any type of filter, highpass, bandpass or lowpass.
Martin
On Mon, Jan 12, 2015 at 9:09 PM, Alexandre Torres Porres < porres@gmail.com> wrote:
Nice I give an impression to be an expert, but filters is just something I've actually recently started studying :)
I'm wondering if by "resonant" filter you mean the same thing as "resonator" filter?
Now you got me... good question, and I'm not sure, haha. The link looks nice btw, will definitely check it. Thanks.
So now I'm even more confused. Is "resonant filter" and "resonator" two different concepts? Maybe I'm having trouble with the english nomenclature and everything.
To be honest and more detailed about the issues I'm encountering, I ask this based on another topic I was discussing with Julius Smith in the Supercollider list, but it went dead and I got no replies. In it I was asking if the object "Resonz" should really be called a "Resonant filter", because it was just a bandpass filter in my opinion. Then Julius was mentioning how "*A resonator is a special case of a passband filter having a nearly zero-width passband.*"
I see he used the term "resonator" and not "Resonant Filter" (as Resonz is described). So yeah, now I'm more confused... is resonator the same as resonant or what?
But anyway, we can bring the discussion into the Pd world, and talk about the [reson~] object, as I will do later on.
I was googling and saw how the term resonant filter could be used to describe a regular bandpass filter. And how the bandpass' center frequency could also be called "resonant frequency". So they might be used in the same way... (accurately or not).
Now here is my opinion. Just like a resonant low pass filter (the [lores~] object in Pd), the concept of resonance in a filter relates to how it adds gain around the resonant frequency.
In the Audio-EQ-Cookbook (link: http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt ) that presents formulas for biquad coeficients you have two different bandpass filters, lets call them BPF1 and BPF2. So, BPF2 has "constant 0 dB peak gain", meaning it doesn't affect anything arounf the center frequency. Now BPF1 says it has "constant skirt gain, peak gain = Q", meaning that the Q or bandwidth controls the gain of the filter. I consider BPF2 to be a regular bandpass filter, whereas BPF1, which adds gain for narrower bandwidths, seems to be a "resonant" one... (which makes me think Resonz shouldn't be described as resonant filter, as it's just a bandpass, or "BPF2").
Oh, there's another term around, the "ringing" filter, which seems to be another term for resonant filter. In SuperCollider they have Ringz, which was supposed to be the same as Resonz object (or a resonant filter for that matter), but they are different like the two different kinds of bandpass in the EQ Cookbook (Ringz = BPF1 / Resonz = BPF2).
Coming into the Pd world we can talk about the [reson~] object. As the name implies, it is a resonant filter. But the helpfile says it is a "Bandpass filter" (damn). Funny enough, in Max, the [reson~] object is said to be indded a *Resonant Bandpass Filter*. So maybe we should update [reson~]'s help file in Pd... But the deal is: [reson~] is actually a bandpass like BFP2 or Resonz, but it has a separate parameter for the gain. Meaning it works basically as a bandpass filter, where changing the Q doesn't affect the gain. But you can also give it a boost or a cut with the gain parameter. By giving it a boost it would behave in a way that I'm considering to be an actual "resonant" filter.
Now let me go ahead and share a patch that I'm writing for my computer music classes. It's about several filters that can be obtained with biquad. So I present Pd's vanilla filters such as [lop~], [hip~] and [bp~]. I also present externals like [lores~] and [reson~] and I do present all the filters from the Audio Eq Cookbook as well. It's in portuguese, and part of a big series of examples, but what the hell...
By the way, I was also able to implement Resonz and Ringz as [biquad~] in Pd, but I don't have it on this example (but to hell with supercollider already, hehe).
So there you can check the behaviour and differences that I've pointed. For [reson~], I have two separate parameters, one is for "Q", and the other one, which is originally "gain", I'm calling the "resonance" parameter. Much like the resonance parameter in [lores~]...
As for the Cookbook filters, BPF2 is what I'm calling a regular "bandpass", and it has a parameter of "Q". As for BPF1, I'm calling it a "resonant filter", and it has a parameter of "resonance" instead of "Q" (but the idea is that more Q gives more gain/resonance).
I hope I'm clear in the midst of so much detail and information. It's just a stupid doubt on the nomenclature of filters, but this kind of issue can be quite a pain in the ass, and the subject of many confusions.
So, in short, I still keep my original question: Are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass? Moreover, what about a resonator? Is my assumption on how to call one a bandpass and a resonant correct or it doesn't have anything to do with the official literature? And how about what Julius Smith had to say?
Cheers
2015-01-12 20:03 GMT-02:00 Brian Fay ovaltinevortex@gmail.com:
Based on your posts in this group, you definitely know more about
filters than I do, so I don't really have an answer to this question - but I'm wondering if by "resonant" filter you mean the same thing as "resonator" filter?
I saw something interesting earlier today about using resonator filters as control sources for FM synthesis: http://tai-studio.org/index.php/projects/sound-programming/complexres/
The paper that is linked in the article has some details on the mathematical implementation of the filter, but that's mostly mumbo-jumbo to me.
On Mon, Jan 12, 2015 at 4:24 PM, Alexandre Torres Porres < porres@gmail.com> wrote:
Hi, are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass?
thanks
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This bit of the wikipedia article on resonance about "Q" ( http://en.wikipedia.org/wiki/Resonance#Q_factor ) mentions a lot of what we read about "Ringing Filter", and how a higher Q will make it "ring" longer... this is what you get from that bandpass in the EQ Cookbook that says it has "constant skirt gain, peak gain = Q" - or what I'm assuming to be a "resonant filter by excellence" or whatever...
cheers
2015-01-13 13:38 GMT-02:00 Alexandre Torres Porres porres@gmail.com:
"*Ultimately I think "resonant" is a general descriptive term for filters, that shouldn't be interpreted as a detail of implementation.*"
I guess you have a point there, and I was also driving to this conclusion.
"*It sounds like the Resonz UGen in supercollider is exactly what Julius Smith is talking about in that description of the two-pole filter.*"
Actually, the Resonz UGen is a Two Pole / Two Zero filter, which is very more closely related to [cyclone/reson~].
A Two-Pole only filter (no zeros) like the one Julius is describing is actually what the [bp~] object is!
"*But then there's the other supercollider filter UGens with "resonant" in the name, which seem more like what Martin was describing - RLPF (resonant low-pass filter) for example is a low-pass filter where you can adjust the resonance near the cutoff.* "
Yep, and this is also much like the [cyclone/lores~] object in Pd. Check that patch I sent for more detailed info on these filters.
I've always assumed that a filter, in order to be called a "resonant filter" or a "resonator" - being it a low pass, a high pass or a band pass -, needed to boost/add gain to a particular cutoff frequency (in the case of lowpass and highpas - which is the case for [lores~] or RLPF) or add gain to some center frequency (in the case of a bandpass) - which is also called "resonant frequency".
The quote from Julius in that link - where he says "*A resonator is a recursive filter that boosts signal amplitude at a particular frequency*"
- is in line with my assumption.
But the concept of resonance in physics, in its utmost purity according to wikipedia, is that it "is the tendency of a system to oscillate with greater amplitude at some frequencies than at others". Meaning that it doesn't really have to add gain to something, but only favor a frequency amongst others... In this context, a bandpass - in general - is a "resonator"...
But it'd be cool if I could find a definitive word about this in the filter literature!
Cheers
2015-01-13 13:16 GMT-02:00 Brian Fay ovaltinevortex@gmail.com:
It sounds like the Resonz UGen in supercollider is exactly what Julius
Smith is talking about in that description of the two-pole filter.
But then there's the other supercollider filter UGens with "resonant" in the name, which seem more like what Martin was describing - RLPF (resonant low-pass filter) for example is a low-pass filter where you can adjust the resonance near the cutoff. I haven't played with this too much myself, but I'm guessing with the right Q value you could drive this to self-oscillation?
Ultimately I think "resonant" is a general descriptive term for filters, that shouldn't be interpreted as a detail of implementation.
On Tue, Jan 13, 2015 at 9:28 AM, Alexandre Torres Porres < porres@gmail.com> wrote:
I'm pending to say that there is no real distinction between "Resonant filter" and a "resonator", and a "bandpass" can be implicitly thought of as a resonator. Here's what I also found in Julius' website
https://ccrma.stanford.edu/~jos/filters/First_Order_Complex_Resonators.html
Pass the mouse cursor over the "Resonator" over the title "First-Order Complex Resonators https://ccrma.stanford.edu/~jos/filters/Two_Pole.html" to see the popup (also attached).
cheers
2015-01-13 1:20 GMT-02:00 Martin Peach chakekatzil@gmail.com:
I was looking at circuit diagrams for analog synthesizers recently and
noticed that the "resonance" control is nothing more than feeding some fraction of the output back to the input. With more feedback oscillation occurs at the cutoff frequency for any type of filter, highpass, bandpass or lowpass.
Martin
On Mon, Jan 12, 2015 at 9:09 PM, Alexandre Torres Porres < porres@gmail.com> wrote:
Nice I give an impression to be an expert, but filters is just something I've actually recently started studying :)
I'm wondering if by "resonant" filter you mean the same thing as "resonator" filter?
Now you got me... good question, and I'm not sure, haha. The link looks nice btw, will definitely check it. Thanks.
So now I'm even more confused. Is "resonant filter" and "resonator" two different concepts? Maybe I'm having trouble with the english nomenclature and everything.
To be honest and more detailed about the issues I'm encountering, I ask this based on another topic I was discussing with Julius Smith in the Supercollider list, but it went dead and I got no replies. In it I was asking if the object "Resonz" should really be called a "Resonant filter", because it was just a bandpass filter in my opinion. Then Julius was mentioning how "*A resonator is a special case of a passband filter having a nearly zero-width passband.*"
I see he used the term "resonator" and not "Resonant Filter" (as Resonz is described). So yeah, now I'm more confused... is resonator the same as resonant or what?
But anyway, we can bring the discussion into the Pd world, and talk about the [reson~] object, as I will do later on.
I was googling and saw how the term resonant filter could be used to describe a regular bandpass filter. And how the bandpass' center frequency could also be called "resonant frequency". So they might be used in the same way... (accurately or not).
Now here is my opinion. Just like a resonant low pass filter (the [lores~] object in Pd), the concept of resonance in a filter relates to how it adds gain around the resonant frequency.
In the Audio-EQ-Cookbook (link: http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt ) that presents formulas for biquad coeficients you have two different bandpass filters, lets call them BPF1 and BPF2. So, BPF2 has "constant 0 dB peak gain", meaning it doesn't affect anything arounf the center frequency. Now BPF1 says it has "constant skirt gain, peak gain = Q", meaning that the Q or bandwidth controls the gain of the filter. I consider BPF2 to be a regular bandpass filter, whereas BPF1, which adds gain for narrower bandwidths, seems to be a "resonant" one... (which makes me think Resonz shouldn't be described as resonant filter, as it's just a bandpass, or "BPF2").
Oh, there's another term around, the "ringing" filter, which seems to be another term for resonant filter. In SuperCollider they have Ringz, which was supposed to be the same as Resonz object (or a resonant filter for that matter), but they are different like the two different kinds of bandpass in the EQ Cookbook (Ringz = BPF1 / Resonz = BPF2).
Coming into the Pd world we can talk about the [reson~] object. As the name implies, it is a resonant filter. But the helpfile says it is a "Bandpass filter" (damn). Funny enough, in Max, the [reson~] object is said to be indded a *Resonant Bandpass Filter*. So maybe we should update [reson~]'s help file in Pd... But the deal is: [reson~] is actually a bandpass like BFP2 or Resonz, but it has a separate parameter for the gain. Meaning it works basically as a bandpass filter, where changing the Q doesn't affect the gain. But you can also give it a boost or a cut with the gain parameter. By giving it a boost it would behave in a way that I'm considering to be an actual "resonant" filter.
Now let me go ahead and share a patch that I'm writing for my computer music classes. It's about several filters that can be obtained with biquad. So I present Pd's vanilla filters such as [lop~], [hip~] and [bp~]. I also present externals like [lores~] and [reson~] and I do present all the filters from the Audio Eq Cookbook as well. It's in portuguese, and part of a big series of examples, but what the hell...
By the way, I was also able to implement Resonz and Ringz as [biquad~] in Pd, but I don't have it on this example (but to hell with supercollider already, hehe).
So there you can check the behaviour and differences that I've pointed. For [reson~], I have two separate parameters, one is for "Q", and the other one, which is originally "gain", I'm calling the "resonance" parameter. Much like the resonance parameter in [lores~]...
As for the Cookbook filters, BPF2 is what I'm calling a regular "bandpass", and it has a parameter of "Q". As for BPF1, I'm calling it a "resonant filter", and it has a parameter of "resonance" instead of "Q" (but the idea is that more Q gives more gain/resonance).
I hope I'm clear in the midst of so much detail and information. It's just a stupid doubt on the nomenclature of filters, but this kind of issue can be quite a pain in the ass, and the subject of many confusions.
So, in short, I still keep my original question: Are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass? Moreover, what about a resonator? Is my assumption on how to call one a bandpass and a resonant correct or it doesn't have anything to do with the official literature? And how about what Julius Smith had to say?
Cheers
2015-01-12 20:03 GMT-02:00 Brian Fay ovaltinevortex@gmail.com:
Based on your posts in this group, you definitely know more about
filters than I do, so I don't really have an answer to this question - but I'm wondering if by "resonant" filter you mean the same thing as "resonator" filter?
I saw something interesting earlier today about using resonator filters as control sources for FM synthesis: http://tai-studio.org/index.php/projects/sound-programming/complexres/
The paper that is linked in the article has some details on the mathematical implementation of the filter, but that's mostly mumbo-jumbo to me.
On Mon, Jan 12, 2015 at 4:24 PM, Alexandre Torres Porres < porres@gmail.com> wrote:
> Hi, are bandpass and resonant filters the same? Or is there a > difference between calling one a resonant and not a bandpass? > > thanks > > _______________________________________________ > Pd-list@lists.iem.at mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list > >
Pd-list@lists.iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
sound on sound's synth secrets backs me up when I say resonant filters amplify bands of frequencies ;)
shttp://www.soundonsound.com/sos/oct99/articles/synthsecrets.htm
not alone after all
2015-01-13 13:48 GMT-02:00 Alexandre Torres Porres porres@gmail.com:
This bit of the wikipedia article on resonance about "Q" ( http://en.wikipedia.org/wiki/Resonance#Q_factor ) mentions a lot of what we read about "Ringing Filter", and how a higher Q will make it "ring" longer... this is what you get from that bandpass in the EQ Cookbook that says it has "constant skirt gain, peak gain = Q" - or what I'm assuming to be a "resonant filter by excellence" or whatever...
cheers
2015-01-13 13:38 GMT-02:00 Alexandre Torres Porres porres@gmail.com:
"*Ultimately I think "resonant" is a general descriptive term for
filters, that shouldn't be interpreted as a detail of implementation.*"
I guess you have a point there, and I was also driving to this conclusion.
"*It sounds like the Resonz UGen in supercollider is exactly what Julius Smith is talking about in that description of the two-pole filter.*"
Actually, the Resonz UGen is a Two Pole / Two Zero filter, which is very more closely related to [cyclone/reson~].
A Two-Pole only filter (no zeros) like the one Julius is describing is actually what the [bp~] object is!
"*But then there's the other supercollider filter UGens with "resonant" in the name, which seem more like what Martin was describing - RLPF (resonant low-pass filter) for example is a low-pass filter where you can adjust the resonance near the cutoff.* "
Yep, and this is also much like the [cyclone/lores~] object in Pd. Check that patch I sent for more detailed info on these filters.
I've always assumed that a filter, in order to be called a "resonant filter" or a "resonator" - being it a low pass, a high pass or a band pass -, needed to boost/add gain to a particular cutoff frequency (in the case of lowpass and highpas - which is the case for [lores~] or RLPF) or add gain to some center frequency (in the case of a bandpass) - which is also called "resonant frequency".
The quote from Julius in that link - where he says "*A resonator is a recursive filter that boosts signal amplitude at a particular frequency*"
- is in line with my assumption.
But the concept of resonance in physics, in its utmost purity according to wikipedia, is that it "is the tendency of a system to oscillate with greater amplitude at some frequencies than at others". Meaning that it doesn't really have to add gain to something, but only favor a frequency amongst others... In this context, a bandpass - in general - is a "resonator"...
But it'd be cool if I could find a definitive word about this in the filter literature!
Cheers
2015-01-13 13:16 GMT-02:00 Brian Fay ovaltinevortex@gmail.com:
It sounds like the Resonz UGen in supercollider is exactly what Julius
Smith is talking about in that description of the two-pole filter.
But then there's the other supercollider filter UGens with "resonant" in the name, which seem more like what Martin was describing - RLPF (resonant low-pass filter) for example is a low-pass filter where you can adjust the resonance near the cutoff. I haven't played with this too much myself, but I'm guessing with the right Q value you could drive this to self-oscillation?
Ultimately I think "resonant" is a general descriptive term for filters, that shouldn't be interpreted as a detail of implementation.
On Tue, Jan 13, 2015 at 9:28 AM, Alexandre Torres Porres < porres@gmail.com> wrote:
I'm pending to say that there is no real distinction between "Resonant filter" and a "resonator", and a "bandpass" can be implicitly thought of as a resonator. Here's what I also found in Julius' website
https://ccrma.stanford.edu/~jos/filters/First_Order_Complex_Resonators.html
Pass the mouse cursor over the "Resonator" over the title "First-Order Complex Resonators https://ccrma.stanford.edu/~jos/filters/Two_Pole.html" to see the popup (also attached).
cheers
2015-01-13 1:20 GMT-02:00 Martin Peach chakekatzil@gmail.com:
I was looking at circuit diagrams for analog synthesizers recently and
noticed that the "resonance" control is nothing more than feeding some fraction of the output back to the input. With more feedback oscillation occurs at the cutoff frequency for any type of filter, highpass, bandpass or lowpass.
Martin
On Mon, Jan 12, 2015 at 9:09 PM, Alexandre Torres Porres < porres@gmail.com> wrote:
Nice I give an impression to be an expert, but filters is just something I've actually recently started studying :)
> I'm wondering if by "resonant" filter you mean the > same thing as "resonator" filter?
Now you got me... good question, and I'm not sure, haha. The link looks nice btw, will definitely check it. Thanks.
So now I'm even more confused. Is "resonant filter" and "resonator" two different concepts? Maybe I'm having trouble with the english nomenclature and everything.
To be honest and more detailed about the issues I'm encountering, I ask this based on another topic I was discussing with Julius Smith in the Supercollider list, but it went dead and I got no replies. In it I was asking if the object "Resonz" should really be called a "Resonant filter", because it was just a bandpass filter in my opinion. Then Julius was mentioning how "*A resonator is a special case of a passband filter having a nearly zero-width passband.*"
I see he used the term "resonator" and not "Resonant Filter" (as Resonz is described). So yeah, now I'm more confused... is resonator the same as resonant or what?
But anyway, we can bring the discussion into the Pd world, and talk about the [reson~] object, as I will do later on.
I was googling and saw how the term resonant filter could be used to describe a regular bandpass filter. And how the bandpass' center frequency could also be called "resonant frequency". So they might be used in the same way... (accurately or not).
Now here is my opinion. Just like a resonant low pass filter (the [lores~] object in Pd), the concept of resonance in a filter relates to how it adds gain around the resonant frequency.
In the Audio-EQ-Cookbook (link: http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt ) that presents formulas for biquad coeficients you have two different bandpass filters, lets call them BPF1 and BPF2. So, BPF2 has "constant 0 dB peak gain", meaning it doesn't affect anything arounf the center frequency. Now BPF1 says it has "constant skirt gain, peak gain = Q", meaning that the Q or bandwidth controls the gain of the filter. I consider BPF2 to be a regular bandpass filter, whereas BPF1, which adds gain for narrower bandwidths, seems to be a "resonant" one... (which makes me think Resonz shouldn't be described as resonant filter, as it's just a bandpass, or "BPF2").
Oh, there's another term around, the "ringing" filter, which seems to be another term for resonant filter. In SuperCollider they have Ringz, which was supposed to be the same as Resonz object (or a resonant filter for that matter), but they are different like the two different kinds of bandpass in the EQ Cookbook (Ringz = BPF1 / Resonz = BPF2).
Coming into the Pd world we can talk about the [reson~] object. As the name implies, it is a resonant filter. But the helpfile says it is a "Bandpass filter" (damn). Funny enough, in Max, the [reson~] object is said to be indded a *Resonant Bandpass Filter*. So maybe we should update [reson~]'s help file in Pd... But the deal is: [reson~] is actually a bandpass like BFP2 or Resonz, but it has a separate parameter for the gain. Meaning it works basically as a bandpass filter, where changing the Q doesn't affect the gain. But you can also give it a boost or a cut with the gain parameter. By giving it a boost it would behave in a way that I'm considering to be an actual "resonant" filter.
Now let me go ahead and share a patch that I'm writing for my computer music classes. It's about several filters that can be obtained with biquad. So I present Pd's vanilla filters such as [lop~], [hip~] and [bp~]. I also present externals like [lores~] and [reson~] and I do present all the filters from the Audio Eq Cookbook as well. It's in portuguese, and part of a big series of examples, but what the hell...
By the way, I was also able to implement Resonz and Ringz as [biquad~] in Pd, but I don't have it on this example (but to hell with supercollider already, hehe).
So there you can check the behaviour and differences that I've pointed. For [reson~], I have two separate parameters, one is for "Q", and the other one, which is originally "gain", I'm calling the "resonance" parameter. Much like the resonance parameter in [lores~]...
As for the Cookbook filters, BPF2 is what I'm calling a regular "bandpass", and it has a parameter of "Q". As for BPF1, I'm calling it a "resonant filter", and it has a parameter of "resonance" instead of "Q" (but the idea is that more Q gives more gain/resonance).
I hope I'm clear in the midst of so much detail and information. It's just a stupid doubt on the nomenclature of filters, but this kind of issue can be quite a pain in the ass, and the subject of many confusions.
So, in short, I still keep my original question: Are bandpass and resonant filters the same? Or is there a difference between calling one a resonant and not a bandpass? Moreover, what about a resonator? Is my assumption on how to call one a bandpass and a resonant correct or it doesn't have anything to do with the official literature? And how about what Julius Smith had to say?
Cheers
2015-01-12 20:03 GMT-02:00 Brian Fay ovaltinevortex@gmail.com:
Based on your posts in this group, you definitely know more about > filters than I do, so I don't really have an answer to this question - but > I'm wondering if by "resonant" filter you mean the same thing as > "resonator" filter? > > I saw something interesting earlier today about using resonator > filters as control sources for FM synthesis: > http://tai-studio.org/index.php/projects/sound-programming/complexres/ > > The paper that is linked in the article has some details on the > mathematical implementation of the filter, but that's mostly mumbo-jumbo to > me. > > On Mon, Jan 12, 2015 at 4:24 PM, Alexandre Torres Porres < > porres@gmail.com> wrote: > >> Hi, are bandpass and resonant filters the same? Or is there a >> difference between calling one a resonant and not a bandpass? >> >> thanks >> >> _______________________________________________ >> Pd-list@lists.iem.at mailing list >> UNSUBSCRIBE and account-management -> >> http://lists.puredata.info/listinfo/pd-list >> >> >
Pd-list@lists.iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
Hello,
On 13.01.2015 04:20, Martin Peach wrote:
I was looking at circuit diagrams for analog synthesizers recently and noticed that the "resonance" control is nothing more than feeding some fraction of the output back to the input. With more feedback oscillation occurs at the cutoff frequency for any type of filter, highpass, bandpass or lowpass.
Martin
when i asked about the difference between the meaning of 'Q' in filters regarding a parametric EQ on a mixing console and the 'Q'/Resonance knob on [analogue synthesizer] filters, i was given an explanation along the lines of 'Q on a parametric eq will adjust the bandwith of the filter while the Q / resonance knob on the other one will adjust the amount of the feedback [back into its input]. Both however will have a similar impact: Reducing the available bandwith will lead to similar results as increasing the amount of "data" in the system.'
hope that isn't too simplified, if it is, i recommend watching Aaron Lantermans lectures on filters on the web.
hth, Tee
hey there - just to offer my armchair two cents on the subject...
i am definitely no electrical engineer but to me Q, resonance and bandwidth are basically the same thing. this is commonly found in parametric EQs - there's not a lot of difference functionally between a fully parametric one band EQ (with gain/cut, frequency center and Q) as compared to something like a bandpass filter on a synth, although synth filtering is generally covering a much wider range to achieve a lot more sculpting possibilities, whereas mixer parametric bands are more limited in scope.
the difference to me between a bandpass filter as traditionally applied in synthesis and a resonant bandpass filter is the additional setting of resonance basically. this acts as a bandwidth control which makes the peak more and more pronounced. in a synth a standard bandpass filter would usually have a single control for frequency, while the bandwidth and gain would be preset. adding a resonance/bandwidth control narrows the range of the band and eventually at high settings it can self oscillate. but the main issue is i believe the same mathematical /signal principle is involved, it's just that at low settings it sounds more subtle and high settings more dramatic.
however since synth filter design is a bit of alchemy, i personally wouldn't be surprised to see unusual methods applied in the process to create a more robust sound, like ganging up bands, or possibly offsetting the resonant peak as compared to the center frequency. i'm totally guessing but i'm curious what things synth companies do or did to create their warm, fat sounds that still sounded different from maker to maker - even later on when they were using chips like the Curtis filters.
scott
On Tue, Jan 13, 2015 at 3:02 PM, Tilo Kremer pd@dadacafe.org wrote:
Hello,
On 13.01.2015 04:20, Martin Peach wrote:
I was looking at circuit diagrams for analog synthesizers recently and noticed that the "resonance" control is nothing more than feeding some fraction of the output back to the input. With more feedback oscillation occurs at the cutoff frequency for any type of filter, highpass, bandpass or lowpass.
Martin
when i asked about the difference between the meaning of 'Q' in filters regarding a parametric EQ on a mixing console and the 'Q'/Resonance knob on [analogue synthesizer] filters, i was given an explanation along the lines of 'Q on a parametric eq will adjust the bandwith of the filter while the Q / resonance knob on the other one will adjust the amount of the feedback [back into its input]. Both however will have a similar impact: Reducing the available bandwith will lead to similar results as increasing the amount of "data" in the system.'
hope that isn't too simplified, if it is, i recommend watching Aaron Lantermans lectures on filters on the web.
hth, Tee
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