Hornresp Filter Wizard
Hi Everyone,
Just letting you know that because of the unprecedented interest shown in the matter, I have started developing a filter wizard for Hornresp.
The tool will have limited capabilities, but hopefully will prove to be of some use, with the ability to model a number of different active and passive filter types. It will operate in much the same way as the existing loudspeaker wizard, with results being calculated in real time so that the effect of filter design changes can be seen immediately. SPL response and diaphragm displacement charts will be provided, together with a schematic diagram for passive filter layouts.
Filter input parameter values will be retained for the duration of the Hornresp session, but will be lost once the program is closed. It will not be possible to permanently save filter settings as part of the data record for a specific design.
Kind regards,
David
Hi Everyone,
Just letting you know that because of the unprecedented interest shown in the matter, I have started developing a filter wizard for Hornresp.
The tool will have limited capabilities, but hopefully will prove to be of some use, with the ability to model a number of different active and passive filter types. It will operate in much the same way as the existing loudspeaker wizard, with results being calculated in real time so that the effect of filter design changes can be seen immediately. SPL response and diaphragm displacement charts will be provided, together with a schematic diagram for passive filter layouts.
Filter input parameter values will be retained for the duration of the Hornresp session, but will be lost once the program is closed. It will not be possible to permanently save filter settings as part of the data record for a specific design.
Kind regards,
David
An externally hosted image should be here but it was not working when we last tested it.
Thanks David!
Hi Martin,
At this stage...
Passive filters:
User-specified networks fitting the attached template, with each of the four RCL branches able to connected in series as shown, or in parallel as suggested by Bjørn (Kolbrek). The attachment shows the maximum number of components possible, connected in full "series" configuration.
Active filters:
Low-pass, high-pass and band-pass Butterworth and Linkwitz-Riley alignments, orders 1 to 8.
Kind regards,
David
Attachments
On the active side it is probably simpler and more flexible to input filter Q instead of limiting to just BW and RL.
In practice todays DSP and even simple plate amps with analog Sallen-Key filters are programmable by Q.
Q factor - Wikipedia, the free encyclopedia
Sallen-Key topology - Wikipedia, the free encyclopedia
In practice todays DSP and even simple plate amps with analog Sallen-Key filters are programmable by Q.
Q factor - Wikipedia, the free encyclopedia
Sallen-Key topology - Wikipedia, the free encyclopedia
Hi Dan,
Apart from specifying a value for Q, what other input parameter values would be required, and what is the formula for the gain of an active filter expressed in such terms? Thanks.
Kind regards,
David
bjorno posted an atachement in post 3300 regarding filters and such ,maybe that helps?
Hi David,
Some resources that come to mind are:
Don Lancaster's Active-Filter Cookbook, and
Active Filter Design Techniques, by TI : http://www.ti.com/lit/ml/sloa088/sloa088.pdf
Regards,
Some resources that come to mind are:
Don Lancaster's Active-Filter Cookbook, and
Active Filter Design Techniques, by TI : http://www.ti.com/lit/ml/sloa088/sloa088.pdf
Regards,
Holy cannoli "Tschebyscheff's" at 10th order is craptastic. I had never even heard that Germanic spin on his name before, always just Chebyschev. It's in the Wikipedia along with several other variants. FYI there are several additional filter design pdf's linked in the Sallen-Key Wikipedia entry.
Hi Everyone,
Thanks for the filter references.
It is still not clear to me how to calculate filter gain given Q and ???
For example, if I wanted to specify a 4th-order Linkwitz-Riley high-pass filter, what input parameters would I use?
With my currently proposed method, the user simply selects the required alignment (Linkwitz-Riley), order (4) and cutoff frequency (100 Hz, for example).
Kind regards,
David
Thanks for the filter references.
It is still not clear to me how to calculate filter gain given Q and ???
For example, if I wanted to specify a 4th-order Linkwitz-Riley high-pass filter, what input parameters would I use?
With my currently proposed method, the user simply selects the required alignment (Linkwitz-Riley), order (4) and cutoff frequency (100 Hz, for example).
Kind regards,
David
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Hello David.
Here are some application examples, and one neat way to display passive filters using ASCI notation.
Q factor bandwidth in octaves filter calculator formula bandwidth - quality factor Q to bandwidth BW width octave convert filter BW octave mastering slope dB/oct steepness EQ equalizer ?? - sengpielaudio Sengpiel Berlin
Calculating the -3 dB cutoff frequencies - quality factor Q factor given center frequency and q factor formula bandwidth in octaves 3 db bandwidth frequency EQ equalizer filter octave 3 dB bandwidth conversion calculator corner frequency half-power f
Active audio filter calculator amplification bandwidth frequency band pass gain - sengpielaudio Sengpiel Berlin ( click on show schematic, I thought it was pretty clever)
Here are some application examples, and one neat way to display passive filters using ASCI notation.
Q factor bandwidth in octaves filter calculator formula bandwidth - quality factor Q to bandwidth BW width octave convert filter BW octave mastering slope dB/oct steepness EQ equalizer ?? - sengpielaudio Sengpiel Berlin
Calculating the -3 dB cutoff frequencies - quality factor Q factor given center frequency and q factor formula bandwidth in octaves 3 db bandwidth frequency EQ equalizer filter octave 3 dB bandwidth conversion calculator corner frequency half-power f
Active audio filter calculator amplification bandwidth frequency band pass gain - sengpielaudio Sengpiel Berlin ( click on show schematic, I thought it was pretty clever)