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TOPIC: Little biquad problem and FIR problem

Little biquad problem and FIR problem 7 months 2 days ago #41015

  • mr-marlen
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Hello!
I found that if we get Biquad filter spreadsheet form this link:
www.minidsp.com/applications/advanced-to...d-biquad-programming
www.minidsp.com/images/fbfiles/files/All...oefs_v1-20101026.zip

Than make filter with low Q values. Our result will be different if we compare it.
When the Q value in spreadsheet about Q=0,2 the result after miniSHARC filtering will be about Q=0,3.
To get 0,2 after miniSHARC filtering i need to put about 0,13 in spreadsheet
Is it some mistake with low values of Q or it is something else?

Also i have got a question about FIR sounding.
When i use "IIR filters config" for my 3 way the bass sounds great. But if i use 96kHz 564taps FIR for each channel which correct only phase from 2kHz to 30kHz, i am getting sad bass sounding. I generates filter using rephase.
Puted here FIR filter and rephase config.
Such filter shouldn't change low freq. sounding but it make it sounds like my 10 inch woofers turned into 5 inch woofers.
Sometimes but not always, on sweep harmonic distortion plots i can see high harmonic distortion to low frequencies with FIR config (sine measurements show that all is clear).
On IIR measurements i can see sometimes uppering 2nd or 4th harmonics, but not all of them.
Maybe it is measuring software problems due to big delay from FIR. But sound perception is similar to increasing harmonic distortion to low frequencies.

Maybe someone could just listen such filter with 96kHz plugin about bass sounding? It will change a little upper frequency sounding and stereo image, but shouldn't change bass perception. For my speakers it make it nearly pergect to minimum phase response.
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Little biquad problem and FIR problem 6 months 3 days ago #41431

  • mr-marlen
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Ok. I have got Hypex FA253 and there is exactly resulting frequency response as i puted in biquads and it is same as in simulator.
With miniSHARC and same biquads i have another frequency response on the output and it is not same as in simulator.
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