FFT Problem (Returns random results)

Question

I\'ve got this code, but it keeps returning random frequencies from 0 to about 1050. Please can you help me understand why this is happening.

My data length is 1024, sam

Answer 1

"random frequencies from 0 to about 1050" - doesn't the typical audio signal consist of a combination of frequencies? Since your sample rate is 8192 Hz, your FFT can detect up to 8192/2 = 4096 Hz. I would expect that you'd see a combination of many frequencies, but I wouldn't call them "random".

Why are you surprised? What did I miss?