Re: [music-dsp] stuck with filter design

2012-11-24 Thread Shashank Kumar (shanxS)
>>> Why so many people use analog prototypes to get a digital filter ? >> >> >> Further to this question, I just came accross this brief but enlightening >> piece by Ken Steiglitz, it discusses the dawn of the use of the BLT and >> music-dsp: >> >> http://www.cs.princeton.edu/~ken/nov05_final.pdf >

Re: [music-dsp] stuck with filter design

2012-11-24 Thread robert bristow-johnson
On 11/21/12 8:41 AM, Ross Bencina wrote: On 19/11/2012 6:33 AM, Shashank Kumar (shanxS) wrote: Why so many people use analog prototypes to get a digital filter ? Further to this question, I just came accross this brief but enlightening piece by Ken Steiglitz, it discusses the dawn of the use

Re: [music-dsp] stuck with filter design

2012-11-21 Thread Dave Gamble
Nice article, and lovely to hear the perspective, but it's the Gelfand-Nymark theorem that guarantees the transfer of knowledge from one domain to another, not the existence of a conformal mapping that proves extremely poor in practical use. Dave. On Wed, Nov 21, 2012 at 1:41 PM, Ross Bencina wr

Re: [music-dsp] stuck with filter design

2012-11-21 Thread Ross Bencina
On 19/11/2012 6:33 AM, Shashank Kumar (shanxS) wrote: Why so many people use analog prototypes to get a digital filter ? Further to this question, I just came accross this brief but enlightening piece by Ken Steiglitz, it discusses the dawn of the use of the BLT and music-dsp: http://www.cs

Re: [music-dsp] stuck with filter design

2012-11-20 Thread Ross Bencina
Thanks Robert, On 20/11/2012 3:21 PM, robert bristow-johnson wrote: Isn't that exactly what you did in the "The Equivalence of Various Methods..." paper? well, no, i didn't think so. Quite right. I should have spent more time looking at the paper. You state the 4 "standard" constraints in t

Re: [music-dsp] stuck with filter design

2012-11-19 Thread robert bristow-johnson
On 11/18/12 11:53 PM, Ross Bencina wrote: On 19/11/2012 3:29 PM, robert bristow-johnson wrote: Why not just put a few constraints on location of poles/zeros on Z plane and get done with it ? what is "it" that you're getting done with? sure we can see that placing poles close to the unit circ

Re: [music-dsp] stuck with filter design

2012-11-19 Thread Wen Xue
been band-limited. But with rational transfer functions this never happens. Xue -Original Message- From: Theo Verelst Sent: Monday, November 19, 2012 9:43 PM To: music-dsp@music.columbia.edu Subject: Re: [music-dsp] stuck with filter design Remember the main rules: Sampled sign

Re: [music-dsp] stuck with filter design

2012-11-19 Thread Theo Verelst
Remember the main rules: Sampled signals can be powerfully processed are nicely fixed (no "analog" noise" and the bits and words specify exact signals), but sampling theory must be understood to enforce some main limitations: the signals of course must have no higher frequency components than

Re: [music-dsp] stuck with filter design

2012-11-19 Thread robert bristow-johnson
On 11/19/12 10:50 AM, Shashank Kumar (shanxS) wrote: LADSPA doesn't enforce anything -- it's really up to the host. But the spec in header does say "For audio it is generally assumed that 1.0f is the `0dB' reference amplitude and is a `normal' signal level." to be honest, I still don't complete

Re: [music-dsp] stuck with filter design

2012-11-19 Thread Bjorn Roche
On Nov 19, 2012, at 4:52 AM, Chris Cannam wrote: > On 18 November 2012 22:24, Bjorn Roche wrote: >> Great. I guess that means LADSPA does not use the usual [-1,1] range. > > LADSPA doesn't enforce anything -- it's really up to the host. But the > spec in header does say "For audio it is general

Re: [music-dsp] stuck with filter design

2012-11-19 Thread Chris Cannam
On 18 November 2012 22:24, Bjorn Roche wrote: > Great. I guess that means LADSPA does not use the usual [-1,1] range. LADSPA doesn't enforce anything -- it's really up to the host. But the spec in header does say "For audio it is generally assumed that 1.0f is the `0dB' reference amplitude and is

Re: [music-dsp] stuck with filter design

2012-11-19 Thread Shashank Kumar (shanxS)
okay, with all this conversation going on.. I feel too excited to say anything sensible.. a lot of thoughts/ideas are going on in my head and I want to analyze them before I say anything. @RBJ: with all due respect to Julius Smith, CCRMA and Melodyne.. their work is quite too complicated/detailed/

Re: [music-dsp] stuck with filter design

2012-11-18 Thread Glen Farrell
For some reason my phone sent the message prior to me finishing the thought. On Nov 18, 2012, at 9:18 PM, Glen Farrell wrote: > When you start talking in terms of systems, where part of the system may > represent a response of a physical system, most of the rules are analog. > > Being that

Re: [music-dsp] stuck with filter design

2012-11-18 Thread Glen Farrell
When you start talking in terms of systems, where part of the system may represent a response of a physical system, most of the rules are analog. Being that this is a music-dsp site, we tend to forget that Transfer function analysis using the s-plane is used in fields like guidance systems, O

Re: [music-dsp] stuck with filter design

2012-11-18 Thread Ross Bencina
On 19/11/2012 3:29 PM, robert bristow-johnson wrote: Why not just put a few constraints on location of poles/zeros on Z plane and get done with it ? what is "it" that you're getting done with? sure we can see that placing poles close to the unit circle causes a boost in dB at the frequencies

Re: [music-dsp] stuck with filter design

2012-11-18 Thread robert bristow-johnson
On 11/18/12 2:33 PM, Shashank Kumar (shanxS) wrote: @ RBJ: Thanks for doing amazing stuff. :) meat and potatoes. check out Julius Smith and CCRMA or companies like Melodyne for the amazing. I have one more question: Why so many people use analog prototypes to get a digital filter ? most

Re: [music-dsp] stuck with filter design

2012-11-18 Thread Ross Bencina
On 19/11/2012 9:24 AM, Bjorn Roche wrote: (Shashank wrote:) I have one more question: Why so many people use analog prototypes to get a digital filter ? Why not just put a few constraints on location of poles/zeros on Z plane and get done with it ? This is a really great question. Indeed. I

Re: [music-dsp] stuck with filter design

2012-11-18 Thread Bjorn Roche
On Nov 18, 2012, at 2:33 PM, Shashank Kumar (shanxS) wrote: > @ Bjorn: > > Yes, you are right. What I thought was scaling is actually clipping. I > removed it and it worked. > Here is the o/p: > http://trystwithdsp.wordpress.com/2012/11/19/basic-lpf-part-2/ Great. I guess that means LADSPA does

Re: [music-dsp] stuck with filter design

2012-11-18 Thread Shashank Kumar (shanxS)
@ Bjorn: Yes, you are right. What I thought was scaling is actually clipping. I removed it and it worked. Here is the o/p: http://trystwithdsp.wordpress.com/2012/11/19/basic-lpf-part-2/ And I have mentioned you and linked that to your blog. If you want me to link it to some other page let me know

Re: [music-dsp] stuck with filter design

2012-11-18 Thread Bjorn Roche
On Nov 18, 2012, at 1:23 AM, robert bristow-johnson wrote: > On 11/18/12 12:00 AM, Ross Bencina wrote: >> You might find these resources helpful: >> >> A. RBJ's EQ cookbook has equations for the filter you want: >> >> http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt >> I've found from fol

Re: [music-dsp] stuck with filter design

2012-11-17 Thread robert bristow-johnson
On 11/18/12 12:00 AM, Ross Bencina wrote: Hello Shashank, I'm interested in this stuff too, but I'm no expert. I've tried to give some pointers below. Hopefully someone else will correct me if I've made an error: On 17/11/2012 8:24 PM, Shashank Kumar (shanxS) wrote: I am a self taught Linux

Re: [music-dsp] stuck with filter design

2012-11-17 Thread Ross Bencina
Hello Shashank, I'm interested in this stuff too, but I'm no expert. I've tried to give some pointers below. Hopefully someone else will correct me if I've made an error: On 17/11/2012 8:24 PM, Shashank Kumar (shanxS) wrote: I am a self taught Linux fanatic who is trying to teach himself Sou

Re: [music-dsp] stuck with filter design

2012-11-17 Thread Bjorn Roche
I don't have all the answers for you, but I have some comments after taking a real quick look at your blog posts: Sonically, the results I hear sound like they are coming from something non-linear. Looking at the code you posted, the only non-linear thing I see is: // scaling the output

[music-dsp] stuck with filter design

2012-11-17 Thread Shashank Kumar (shanxS)
Hey everyone! I am a self taught Linux fanatic who is trying to teach himself Sound Processing. I have basic idea of signal processing. My aim is to develop an intuition by which I can design a 2nd order IIR audio filter given a 3dB bandwidth and a center frequency. I am not following any specif