Reading data in PyAudio

Question

I've looked at all the example code but can't seem to read audio from my RME card using PyAudio. here is the code I'm using:

import wave
import scipy.io.wavfile as waveIO
from __future__ import division
import pyaudio
import time

p=pyaudio.PyAudio()

def record_audio(RECORD_SECONDS,MIC_channel):

   CHUNK = 1024
   FORMAT = pyaudio.paInt16
   CHANNELS = 1
   RATE = 44100

   stream_in = p.open(rate=RATE,
                channels=CHANNELS,
                format=FORMAT,
                input=True,
                input_device_index=MIC_channel,
                frames_per_buffer=CHUNK)

   frames = ""

   t=time.time()
   for i in range(0, int((RATE / CHUNK) * RECORD_SECONDS)):
       data = stream_in.read(CHUNK)
       frames=frames+data

   elapsed=time.time() - t

   print('I read the data in %f seconds' %elapsed)


   stream_in.stop_stream()
   stream_in.close()


   return frames

record_audio(5,40)

I expect this code to read 5 seconds of audio. However, the audio I get is just noise so I added the timer lines to check. the answer I get is 'I read the data in 0.001 seconds'.

The length of the frames string is correct (sample_rate*2 (bytes per sample) * 5 seconds). The number of frames is also correct. So it just looks like the data=stream_in.read(CHUNK) line takes up almost no time while I expected it to take CHUNK/RATE.