Equalizer

[normanalie]

Hello, currently the EQ web interface display 3 bands (Bass, mids and highs) but the code only takes two bands into account.
Is there a reason for that ? DSP capabilities?

[CarlosDerSeher]

The EQ isn't quite finished yet. I didn't find time to do it. I'd like to make all those EQ / DSP capabilities accessibly from the web interface at some point though. Maybe you can implement needed functionality yourself?

[CarlosDerSeher]

I would use NVS flash. Have a look at IDF doc

Hopefully NVS parition will be big enough to store all the data you need. If not we would need to adjust sizes in partition.csv

[normanalie]

Thanks. NVS is big enough to store filter params.
I've been playing with filter types, and I don't understand why there is no gain parameter for the peak filter ?
esp_err_t dsps_biquad_gen_peakingEQ_f32(float *coeffs, float f, float qFactor);
I think I missed something.

[CarlosDerSeher]

I'd expect a gain factor too. Some info about digital filters can be found here.

Not sure how to proceed here maybe ask on espressif github page?

[CarlosDerSeher]

Not sure how to read the implementation. It seems gain is set to 1 but still the formulas don't add up. Which IIR form did they implement?

[CarlosDerSeher]

Ok probably more research on dsp needs to ne done. See here for example. Quality factor is related to -3dB bandwidth of the filter.