How can I get the spectrum out of a 2048 float32Array

[JSmithOner]

I've looked at your documentation and couldn't find a real situation example where the array is filled with data.So my question is how can I get the Spectrum values of a float32array filled with audio values.

Thanks in advance

[skoerfgen]

Recently I asked myself the same thing. Hope this helps:

// example audio values
const myFloat32Array = new Float32Array(4096).map(i=>Math.random()*2-1);

const f = new FFT(4096);
const out = f.createComplexArray();
f.realTransform(out, myFloat32Array);

const getMagnitude=(arr)=>{
	// input "arr" contains [ real0, imaginary0, real1, imaginary1, ... ];
	// pairwise get scalar magnitude (power)
	return arr.reduce((a,c,i)=>{
		if (i%2===0) a.push(Math.hypot(c,arr[i+1]));
		return a;
	},[]);
};

// "out" has length 4096*2, only use left half (containing the Fourier Transform's complex output)
const spectrum=getMagnitude(out.slice(0,out.length/2));
// result has now length 2048 (half the fftSize)

[JSmithOner]

@skoerfgen

Recently I asked myself the same thing. Hope this helps:

// example audio values
const myFloat32Array = new Float32Array(4096).map(i=>Math.random()*2-1);

const f = new FFT(4096);
const out = f.createComplexArray();
f.realTransform(out, myFloat32Array);

const getMagnitude=(arr)=>{
	// input "arr" contains [ real0, imaginary0, real1, imaginary1, ... ];
	// pairwise get scalar magnitude (power)
	return arr.reduce((a,c,i)=>{
		if (i%2===0) a.push(Math.hypot(c,arr[i+1]));
		return a;
	},[]);
};

// "out" has length 4096*2, only use left half (containing the Fourier Transform's complex output)
const spectrum=getMagnitude(out.slice(0,out.length/2));
// result has now length 2048 (half the fftSize)

thank you meanwhile I figured it out