Volume Control Does not Seem to Work

[RickLloyd24]

Sorry if this is a stupid question. I am using the file streams-i2s-filter-i2s.ino example. Everything works but the volume is very low. I tried adding a VolumeStream and used multiple values (0.3 to 0.9) but it did not change the volume. What am I doing wrong? I enclosed the complete code.

On other questions what is the maximum number of coefficients you can use?

#include "AudioTools.h"
AudioInfo info(32000, 2, 16);
I2SStream in;
I2SStream out;
VolumeStream gain(in);

// copy filtered values
FilteredStream<int16_t, float> filtered(in, info.channels); // Defiles the filter as BaseConverter
StreamCopy copier(out, filtered); // copies sound into i2s

// define FIR filter parameters
float coef[] = { 0.021, 0.096, 0.146, 0.096, 0.021};

// Arduino Setup
void setup(void) {
// Open Serial
Serial.begin(115200);
// change to Warning to improve the quality
AudioLogger::instance().begin(Serial, AudioLogger::Info);

// setup filters for all available channels
filtered.setFilter(0, new FIR(coef));
filtered.setFilter(1, new FIR(coef));

// start I2S in
Serial.println("starting I2S...");
auto config_in = in.defaultConfig(RX_MODE);
config_in.copyFrom(info);
config_in.i2s_format = I2S_STD_FORMAT;
config_in.is_master = true;
config_in.port_no = 0;
config_in.pin_ws = 22;
config_in.pin_bck = 23;
config_in.pin_data = 21;
// config_in.fixed_mclk = sample_rate * 256
// config_in.pin_mck = 3

in.begin(config_in);

// start I2S out
auto config_out = out.defaultConfig(TX_MODE);
config_out.copyFrom(info);
config_out.i2s_format = I2S_STD_FORMAT;
config_out.is_master = true;
config_out.port_no = 1;
config_out.pin_ws = 25;
config_out.pin_bck = 14;
config_out.pin_data = 26;
out.begin(config_out);

// set initial volume
gain.begin(info); // we need to provide the bits_per_sample and channels
gain.setVolume(0.9);

Serial.println("I2S started...");
}

// Arduino loop - copy sound to out
void loop() {
copier.copy();
}

[pschatzmann]

gain is not part of the processing chain, so it does not have any impact!

[RickLloyd24]

How do I make gain part of the processing chain?

[RickLloyd24]

I understand your response and was able to get it working.