3.2 Sound recording fails


Often a system may not work well because the recording itself has not been performed properly. This section describes

  1. A method to confirm that the recording has been performed properly, and

  2. The usual reasons that sound recording is not performed properly and measures to correct these problems.


Try to record after reading the recipe Learning sound recording. It will be easier to confirm later if a user says something for sound recording. Next, confirm that the file has been recorded using software that can display waveforms, such as Audacity and wavsurfer. When recording using more than three microphones, it is convenient to use software that accepts multiple channels. If the display shows that each waveform has been recorded by all channels to which microphones have been connected, the recording has been successfully completed. If there are almost no amplitudes or clipping, confirm that

Each microphone is working properly

Connect each to a familiar PC and confirm that each can record sounds.

Each microphone is connected properly

Confirm if each is properly connected. Unplug a microphone and plug in again.

The microphone has been plugged in

Some types of microphones cannot access a sufficient sound volume without an external power source (called plug in power). Although some sound recording devices supply power, if a microphone requires plug in power and the device does not supply power, an external power supply is required. Confirm by consulting the manuals for both the microphone and the device.


Speech recognition systems often do not work properly because the sound itself was not recorded or not recorded properly. particular, for a system with a large number of microphones, it is important to confirm that each microphone can record sounds before operating the software.

See Also

A detailed method of sound recording is described in Learning sound recording. A detailed description of sound recording devices are described in Chapter 7 in the HARK  document.