Generating a sine wave sound in python

问题

I've been trying to generate a sine wave using the following code and playing it thought my speakers, but it sounds horrible. Anyone knows why? It does not sound like a sine wave.

       dur = int(FS * float(duration) / 1000)
       for i in range(dur):
         a = frequency * i * 2 * math.pi / FS
         y = math.sin(a)
         outbuf[i] = y * 0.2

p = pyaudio.PyAudio()
stream = p.open(format=pyaudio.paFloat32, channels=1, rate=44100, output=True)
stream.write(outbuf)
stream.stop_stream()
stream.close()
p.terminate()

play_sound("sine", 1000, 1, 1000)

回答1:

the audio buffer must be packed into binary, for python3 use b''.join(struct.pack also simplified the sin curve synthesis by moving the angle theta increment constant to outside of the loop

import pyaudio
import numpy as np
import math
import struct

FS = 44100  #  frames per second, samples per second or sample rate

def play_sound(type, frequency, volume, duration):

   generate_sound(type, frequency, volume, duration)

def generate_sound(type, frequency, volume, duration):

    outbuf = np.random.normal(loc=0, scale=1, size=int(float(duration / 1000.0)*FS))

    if type == "sine":
        dur = int(FS * float(duration / 1000.0))
        theta = 0.0
        incr_theta = frequency * 2 * math.pi / FS # frequency increment normalized for sample rate
        for i in range(dur):
            outbuf[i] = volume * math.sin(theta)
            theta += incr_theta

    p = pyaudio.PyAudio()
    stream = p.open(format=pyaudio.paFloat32, channels=1, rate=FS, output=True)
    data = b''.join(struct.pack('f', samp) for samp in outbuf) # must pack the binary data
    stream.write(data)
    stream.stop_stream()
    stream.close()
    p.terminate()

play_sound("sine", 220, 0.8, 1000)  #  duration in milliseconds

来源：https://stackoverflow.com/questions/61576953/generating-a-sine-wave-sound-in-python