diyAudio (
-   Digital Source (
-   -   FIR filters: how to get the filter coefficients? (

4real 25th August 2005 08:10 PM

FIR filters: how to get the filter coefficients?
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.

4real 25th August 2005 09:28 PM

Here a java applet that should do the trick:

I only need to know if the coefficients are compatible with BruteFIR.

Charles Hansen 26th August 2005 03:40 AM

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.

DSP_Geek 26th August 2005 03:53 AM

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).

It's a hundred bucks; I've gotten many times that much use from it.

Frankie-Bob says two thumbs up!


disclaimer: no ties to iowegian whatsoever, just a satisfied customer.

4real 26th August 2005 09:30 AM

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.

blu_line 26th August 2005 11:11 AM

And i got a few more of which i do not have the links available currently.



blu_line 26th August 2005 11:20 AM


And i got a few more of which i do not have the links available currently.
I do :D



4real 26th August 2005 11:35 AM

Thanks those look great.

But I still think my first java applet is the most usable, since I also have sources of that one.

RR 26th August 2005 02:37 PM


Try this Octave script:

4real 26th August 2005 02:40 PM

Thanks! That is really nice! I'll look into that as soon as possible!

All times are GMT. The time now is 04:08 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 18.75%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio