trying to use the Low Pass Filter Class

[SnazzyBlanket]

Hello

I feel a bit dumb but I wanted to ask if I am declaring the low pass filter properly. all I get are errors

FilteredStream<int16_t, float> filt_stream(sqr_stream, info.channels); // Defiles the filter as BaseConverter

setup
filt_stream.setFilter(0, new LowPassFilter(440.0f, 44100.0f, 0.5f));

"audio_tools::LowPassFilter::LowPassFilter(float frequency, float sampleRate, float q = (0.7071F)) [with T=float]" (declared at line 319 of "/Users/cricketbee/Documents/PlatformIO/Projects/Billy Club/ESP32 CODE/ESP32-S3_TFT-TOUCH-DAC-ENCODER/lib/arduino-audio-tools/src/AudioFilter/Filter.h") is inaccessible

[pschatzmann]

I think there is something wrong with the version that you currently have in PlatformIO. I suggest to delete the .pio folder to trigger a reload of the actual version.

ps. I was just double checking the code and indeed there was an error in my code on line 319! Strange that Arduino did not complain.

[SnazzyBlanket]

I got the filter working with intitial cutoff , SR and Q Values but unlike other classes I do not see any methods like SetCutoff, SetQ in order to change the values in real time (say via a pot)

I wanted to do something like this but for Cutoff and Q

// Sets the volume control from a linear potentiometer input
void updateVolume() {
// Reading potentiometer value (range is 0 - 4095)
float vol = static_cast(analogRead(volumePin));
// min in 0 - max is 1.0
player.setVolume(vol/4095.0);
}

[pschatzmann]

I am not sure what you are referring to.
If you talking about the low pass filter, why don't you just call the begin method with different parameters ?

AudioInfo info(44100, 2, 16);
I2SStream in;
FilteredStream<int16_t, float> filt_stream(in, info.channels); // Defiles the filter as BaseConverter
LowPassFilter<float> lp0(440.0f, info.sample_rate, 0.5f);

void setLowPassFreqency(float freq) {
  // change filter parameters
  lp0.begin(freq, info.sample_rate, 0.5f);
}

void setup() {
  ...
  filt_stream.setFilter(0, lp0);
  ...
}

[SnazzyBlanket]

because then I would need to call lpf.begin every signel adc read if i wanted to use an external knob with analogRead.

in other words I want to be able to continously change the parameter values using a knob (or any other control signal)

thanks

[pschatzmann]

No you would call setLowPassFreqency only when the value has changed. You could even add the logic to setLowPassFreqency that you call begin only when the freq has changed

[SnazzyBlanket]

ok so it is not the same as the ADSR or sine wave classes

with those classes you have a .begin for setup but then you can manipulate via the setterMethods

there are no setter methods in the lowpassFilter and I was just trying to make sure i was not missing something

normally you would call the begin in setup and then the setter in your loop

sineWave.begin(info, N_C4);

sineWave.setFrequency(knob1)

[SnazzyBlanket]

Ahh I see i can do exactly what I would like to do with the filter in Maximillian