如何使PyAudio的嘈杂输出静音？

import pyaudio

pa = pyaudio.PyAudio()

input_device_index = pa.get_default_input_device_info()['index']
output_device_index = pa.get_default_output_device_info()['index']

stream = pa.open(input_device_index=input_device_index,
                 output_device_index=output_device_index,
                 format=pyaudio.paInt16,
                 channels=1,
                 rate=44100,
                 input=True,
                 output=True)

while True:
    data = stream.read(1024)
    stream.write(data)

import numpy as np

while True:
    data = stream.read(1024)
    data = np.frombuffer(data, dtype=np.int16)
    data[np.abs(data) < threshold] = 0
    data = data.astype(np.int16)
    stream.write(data.tobytes())