Devices Preferences

Gale 27Feb13: ToDo-2 Please review WASAPI text.

Click on any of the other Preferences sections in the above image to go directly to that Preferences page.

Interface

• Host: Selects the particular interface with which Audacity communicates with your chosen playback devices. On Windows, the choice is between MME (the Audacity default, more compatible), Windows DirectSound (a slightly modern replacement), Windows WASAPI (Audacity currently provides only "loopback" inputs for this host - these inputs can be used to record computer playback on Windows Vista and later) and Windows WDM-KS a (host which bypasses the kernel mixer that is normally used to mix outputs from multiple applications and can thus provide very low latencies). In Linux there is often only one option: ALSA, other options could be OSS and/or Jack Audio Connection Kit (also known as "Jack" or "Jackd"). On Mac OS X the only choice is Core Audio. Generally you will want to use the default host.
  • On Windows XP or earlier (given a recent computer), WDM-KS's and DirectSound's much shorter path to the hardware should produce lower latency than MME. Under WDM-KS, only one application is allowed to access the audio device at a time. So for example if you are already playing audio in the web browser or another application, you will not be able to play audio in Audacity using the same device that the web browser is using.
  • On Windows Vista, Windows 7 and Windows 8:
    • Windows DirectSound and WDM-KS may have only slightly lower latency than MME because both interfaces are emulated. However if you reduce "Audio to Buffer" in Recording Preferences you can achieve extremely low latencies. Just reduce "Audio to buffer" until the sound begins to break up.
    • Windows WASAPI  host currently provides only "loopback" inputs. These inputs can only be used to record computer playback.

  Selecting Windows DirectSound and enabling both "Exclusive Mode" boxes in Windows "Sound" allows Audacity to request audio direct from the device without resampling or kernel mixing. If you use WDM-KS on Windows Vista or later, the currently playing application has exclusive access to the audio device irrespective of Windows "Exclusive Mode" settings. See the Wiki page for Windows 7 for more explanation.
  • Using: Gives the version number and build date of the PortAudio Audio I/O interface library with which Audacity was built.

  Playback

  • Device: Selects the device used for playback.

  Recording

  • Device: Selects the device used for recording.
  On Windows, each entry for recording device consists of the input type (such as microphone), followed by the name of the audio device the input belongs to. If you have multiple audio devices, the list will be grouped so that inputs of each device are grouped together. The input level of the selected device can be adjusted in Mixer Toolbar, but device selection is no longer made there.
  • Channels: 1 (Mono), 2 (Stereo) or the number of channels that are provided by the drivers of your sound device. On most inbuilt sound devices, especially on Windows, only mono or stereo will be available. For some devices on Windows, choosing Windows DirectSound in "Host" above may be more likely to reveal options for recording more than two channels. On some devices capable of recording more than two channels, an explicit "multi" device may appear in the "Device" drop-down for recording all the channels simultaneously.