Hey there.
To make one thing clear: I don't want to talk about the pro's and con's of FIR filters! So don't start on that 😉
So, what do I want to talk about then? Well, I'm interested in experimenting with an active 3-way speaker system. For this, I would like to use BruteFIR (like some others here on the).
But the thing is: you'll need to create the filter coefficients yourzelf. And sadly, I'm not an expert on that (I know the basics though). So I'm looking for some free software (preferably linux command line tools), to create nice phase-linear filters with as little pre-ringing as possible, with a fairly small tab size. Up until now, I didn't find anything usable. I looked at the sources of AlmusVCU (same author as BruteFIR), and found some stuff there to create some bastic filters, but I'd have to hack it a lot to create a usefull tool 😉 . So If you know some great tools, or some tutorial to use Matlab or Octave, please let me know! Also something to visualize the coefficients (frequency response) would be great.
To make one thing clear: I don't want to talk about the pro's and con's of FIR filters! So don't start on that 😉
So, what do I want to talk about then? Well, I'm interested in experimenting with an active 3-way speaker system. For this, I would like to use BruteFIR (like some others here on the).
But the thing is: you'll need to create the filter coefficients yourzelf. And sadly, I'm not an expert on that (I know the basics though). So I'm looking for some free software (preferably linux command line tools), to create nice phase-linear filters with as little pre-ringing as possible, with a fairly small tab size. Up until now, I didn't find anything usable. I looked at the sources of AlmusVCU (same author as BruteFIR), and found some stuff there to create some bastic filters, but I'd have to hack it a lot to create a usefull tool 😉 . So If you know some great tools, or some tutorial to use Matlab or Octave, please let me know! Also something to visualize the coefficients (frequency response) would be great.
Here a java applet that should do the trick:
http://www.dsptutor.freeuk.com/remez/RemezFIRFilterDesign.html
I only need to know if the coefficients are compatible with BruteFIR.
http://www.dsptutor.freeuk.com/remez/RemezFIRFilterDesign.html
I only need to know if the coefficients are compatible with BruteFIR.
Momentum Data Systems makes some nice design packages. You can get a demo version of QED 1000 to play around with, but it won't give coefficients unless you purchase it for $895 (dongle protected). There is a student version for $99 with fewer features. You will have to see if you can live with its limitations.
http://www.mds.com/Products/product.asp?prod=QED-COMPARE
http://www.mds.com/Products/product.asp?prod=QED-COMPARE
If you do this for a living, you could do far worse than ScopeFIR. It's a nice little Windows package with all the graphing you could possibly want, including graphs of imported coefficients, which comes in quite useful when using subtractive FIRs for the other band ((delayed signal) - FIR LP = FIR HP).
http://www.iowegian.com
It's a hundred bucks; I've gotten many times that much use from it.
Frankie-Bob says two thumbs up!
Francois.
disclaimer: no ties to iowegian whatsoever, just a satisfied customer.
http://www.iowegian.com
It's a hundred bucks; I've gotten many times that much use from it.
Frankie-Bob says two thumbs up!
Francois.
disclaimer: no ties to iowegian whatsoever, just a satisfied customer.
All very nice, but there are two problems: those are Windows tools, and those are NOT free 😉
3'rd problem is that I want to integrate in into a home-made crosover designer that will spit out a BruteFIR config file automagicly.
3'rd problem is that I want to integrate in into a home-made crosover designer that will spit out a BruteFIR config file automagicly.
http://www.geocities.com/weiruan97/dfd/dfilter.html
And i got a few more of which i do not have the links available currently.
grtz
Simon
And i got a few more of which i do not have the links available currently.
grtz
Simon
Thanks those look great.
But I still think my first java applet is the most usable, since I also have sources of that one.
But I still think my first java applet is the most usable, since I also have sources of that one.
scilab is a open source work-alike for MatLab and has many equivalent script packages for specific engineering domains - including signal processing packages
home:
http://scilabsoft.inria.fr/
signal processing functions:
http://pauillac.inria.fr/cdrom/www/scilab/whatis/node27.html
200+ page signal processing manual:
http://pauillac.inria.fr/cdrom/ftp/scilab/documentation/pdf/signal.pdf
home:
http://scilabsoft.inria.fr/
signal processing functions:
http://pauillac.inria.fr/cdrom/www/scilab/whatis/node27.html
200+ page signal processing manual:
http://pauillac.inria.fr/cdrom/ftp/scilab/documentation/pdf/signal.pdf
Thanks jcx! That looks like some neet tools.
I still like the java applet though, since it can find the optimal length of the filter, and passband and attenuation be set. Best of all is that I can simply use the stuff directly in my onw tools (of course I'll need to straighten out some bugs).
Scilab looks fine too, but I'd have to do more work to have it usable. But I guess, it is a lot more flexible! So it might very well be worth it.
I still like the java applet though, since it can find the optimal length of the filter, and passband and attenuation be set. Best of all is that I can simply use the stuff directly in my onw tools (of course I'll need to straighten out some bugs).
Scilab looks fine too, but I'd have to do more work to have it usable. But I guess, it is a lot more flexible! So it might very well be worth it.
Looked into the PDF a little closer.
It really is a great tutorial. It's all I'll ever need, and it's free for all 😀
It really is a great tutorial. It's all I'll ever need, and it's free for all 😀
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