Bandpass filter has no effect - attempting to make multi bandpass filter?

Development
1

I am absolutely certain there are 100 better ways to do what I am attempting to do with this code. If anybody happens to know how please let me know. Essentially, I am attempting to create an IIR bandpass filter with an arbitrary amount of center frequencies (in my code I call them formants). My overall goal is the make a vowel like speech generator. Unfortunately, the filter seems to have no effect on the sound I produce (using a sawtooth synth). I have created an array of IIRFilter objects with

filter[i].setCoefficients(IIRCoefficients::makeBandPass(sampleRate, freq[i]));

And heres where It gets a little wonky. To achieve the multi bandpass filter. I am applying each filter individually and then averaging the result of each of them. That code is as follows

	float* outputSamplesPtr = new float[numSamples]();
	float* filterSamplesPtr = new float[numSamples];

	for (int formantIdx = 0; formantIdx < formantFreqs; formantIdx++) {
		memcpy(filterSamplesPtr, inputSamplesPtr, numSamples * sizeof(float));
		filter[formantIdx].processSamples(filterSamplesPtr, numSamples);
		for (int sample = 0; sample < numSamples; sample++) {
			outputSamplesPtr[sample] += filterSamplesPtr[sample] / formantFreqs;
		}
	}

	memcpy(inputSamplesPtr, outputSamplesPtr, numSamples * (sizeof(float)));
	delete[] outputSamplesPtr;
	delete[] filterSamplesPtr;

When I noticed it had no effect I also tried to cascade the entire system by putting the above code entirely in a for loop.

for (int order = 0; order < cascadeCount; order++)

But still no sound. I know this is probably the worst possible complexity to achieve my goal. But I don’t know any other way to accomplish it. Maybe it has something with the Q factor? I’m not sure.