How can I mix recordings from two separate devices into one clip?

Jaimin k November 2, 2014

I took the recording of an important meeting using two android devices (let’s call them device A and device B) . The meeting table is 25 feet long and attended by about 15 people. I placed each recording device at each end of the table. Each device can only record the voice of people seated near it. My question is: how do I combine the recording of both Device A and Device B so that I can have a single recording that clearly captured the voice recording of all people in the meeting?

  1. Susendeep.D
    November 2, 2014 at 3:24 pm
  2. Oron J
    November 2, 2014 at 12:12 pm

    I would suggest transferring them to a PC (or Mac), importing both recordings into an audio editor and aligning them. Here are instructions for doing this in Audacity, but you could use any good audio editor.
    Open Audacity and choose File=>Import=>Audio...
    Select both files and Open (or you can import them one at a time, the result is the same).
    Expand the window so to fill the screen. You will see each recording in a separate pane. If they are stereo recordings, each of them would show both tracks.
    Find the beginning of the conversation, and zoom in on it using the magnifying glass so that you can see perhaps 30 seconds of speech.
    Choose a distinct pattern on the screen that appears on all recordings (although obviously it will be at slightly different points), and zoom in on it.
    Using the time-shifter tool (double arrow), move one recording to that the pattern appears exactly at the same point in time (in other words, so that it one of them appears directly above the other).
    Zoom in more and refine the process.
    Put the cursor a bit earlier in the recording and play a few seconds (tip: use the space bar to start/stop playing). If they sound fine, great. If not, you may need to zoom in further to make the alignment more accurate.

    This approach works, but it can be hard work. In the future, make a sharp sound after you press "record" on both devices, but before the actual conversation starts. This will help with the alignment. A sharp noise can be clapping your hands, or dropping a metal object etc - anything that is loud and quick.