IIRFilter BandPassFilter Has No Effect!


Im trying to setup the bandpassfilter but it seems to have no effect regardless of the values I choose whereas the lowpass or highpass work ok, is there something different with the implementation of the bandpassfilter.

[code]//This is OK

//This has no effect!

The bandpass should be passing frequecies within a certain range, Q value should be the center frequency of a filter divided by the bandwidth, so to map upper and lower bounds of a certain frequency range I calculate the appropriate Q value. How is the effect of the gainvalue here calculated? If I setup the bandpass filter as

makebandpass(samplerate,200,2,0.1f) This is passing High Frequencies why?(Should be passing 150-250Hz) Also setting the gain value to 1.0f makes the bandpass filter have no effect what so ever.


The gain is the factor to boost the centre frequency by - so if it’s more than 1, it’ll boost, less than 1 and it’ll cut it.


Thanks jules, but my question is if you try

Shouldn’t this be passing low frequencies? Q value of 2 implies bandwidth of 100 (200/100 = 2) therefore only a range between approx 150 to 250, but all you hear is high frequencies?


If the gain is 1, it won’t do anything at all. It’s the same thing as the tracktion e.q. - have a play with that to see how it works visually.