Hello all
I have made a free, nonagging, filter simulation program for designing passive filters.
https://sites.google.com/site/passivefilter/
The filter syntesis program emulates a passive 4 order filter.
Take a look at the screenshots on the homepage.
The main thing is that the program uses the impedance of the speaker so more real results is calculated compared to simple fixed impedance calculators.
I also like the abillity to correlate against a active filter response, since many of us is used to designing active digital filters. Can also be used for hybrid filter design.
In my exprience digital filters works very well. I still think you can save some money using a passive filter from 2000Hz and up. Then the component values are small and "cheap", the power needed is low and you could save a DAC, filterstage and poweramp. (Or a active filterstage if it is hybrid.)
(This assuming a minimum 3 way speaker, and no bandpass passive filter).
Feel free also to design an all passive 3 way design or a mix of n way active and n way passive
.
You could even make 3 way modules, measure them and put them together by importing the module impedances and SPLs.
For the real filter geeks: Enjoy the complex plots!
For the beginner and learner: Look how the transfer function changes as the filtervalues are changed by the program.
I think the program can be run from a stick and all user settings can be saved in a single xmlfile. The program do not use the register.
The .xml file can also be used to exchange designs in a simple way for users of the program.
I have achived simulation/real filter with 0.5 dB max error for 4th order HP filter with the program.
Hope you like it
Regards Torgeir
I have made a free, nonagging, filter simulation program for designing passive filters.
https://sites.google.com/site/passivefilter/
The filter syntesis program emulates a passive 4 order filter.
- 3 bands: High, mid and low
- Imports RoomEQwizard impedance and SPL data for each band
- R,L and C on each node
- Calculates Butterworth 1 to 4 order for both active and passive
- Automatic change components and correlates with active filer spesified by user. From 100 changes/second.
- Look at curves as components are changing!
- Curves for all components, tranfer function and SPL
- Magnitude and phase in dB and degrees + plot in complex chartesian diagram, s+jw
- Saves all settings as xml, no use of registers
- Based on complex numbers and Cauer/prototype networks.
- Windows desktop program coded in Visual Basic.
- Uses mathdotnet library. http://numerics.mathdotnet.com
- Prerequisites: Microsoft .NET framework 4.5.2.
The installer will install 4.5.2 from the Microsoft site if it is not already installed.
Take a look at the screenshots on the homepage.
The main thing is that the program uses the impedance of the speaker so more real results is calculated compared to simple fixed impedance calculators.
I also like the abillity to correlate against a active filter response, since many of us is used to designing active digital filters. Can also be used for hybrid filter design.
In my exprience digital filters works very well. I still think you can save some money using a passive filter from 2000Hz and up. Then the component values are small and "cheap", the power needed is low and you could save a DAC, filterstage and poweramp. (Or a active filterstage if it is hybrid.)
(This assuming a minimum 3 way speaker, and no bandpass passive filter).
Feel free also to design an all passive 3 way design or a mix of n way active and n way passive
. You could even make 3 way modules, measure them and put them together by importing the module impedances and SPLs.
For the real filter geeks: Enjoy the complex plots!
For the beginner and learner: Look how the transfer function changes as the filtervalues are changed by the program.
I think the program can be run from a stick and all user settings can be saved in a single xmlfile. The program do not use the register.
The .xml file can also be used to exchange designs in a simple way for users of the program.
I have achived simulation/real filter with 0.5 dB max error for 4th order HP filter with the program.
Hope you like it
Regards Torgeir
Last edited:
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