AV202-B USB Audio Grabber Issues on macOS

How can I prevent clicky recordings on Mac?

There are several possible fixes.

  • Open Devices Preferences and adjust the "Buffer Length" setting. Reduce the setting to 0 milliseconds. If recording breaks up or does not start, increase "Buffer Length" in increments of 10 milliseconds until recording is smooth.
  • If you are recording from an external USB or FireWire interface, open /Applications/Utilities/Audio MIDI Setup and select the device. On the Input tab, make sure that the sample rate and number of channels matches with those chosen in Audacity.
  • Turn off WiFi.
  • Mitigate power saving features in Mavericks or later that can interfere with recordings.
    • Right-click or Control-click Audacity.app then "Get Info" and enable the "Prevent App Nap" checkbox. This should prevent the Mac putting Audacity into a paused state when it does not have focus.
    • A few users have reported that Antipop helps. This prevents the Mac shutting down the audio system when there is no playback.

See also:


How can I record without small skips (dropouts) or duplications?

You may have been experiencing dropouts and not noticing, they are not discernible while recording only on playback. So Audacity could now appear much worse than previous releases, when in actual fact Audacity is just alerting you to a problem that you previously would not have been aware of - or might have put down to a bad microphone or poor recording technique. 

If it sounds like recording is skipping, or small fragments are sometimes missing, this means that Audacity cannot write the audio to disk fast enough to keep up with what it's recording. You may not hear skips while listening during the recording, but you will hear them on playback.

Audacity settings

  • Reduce screen redrawing: Zoom out to at least the entire length you'll be recording, or in Tracks Preferences, uncheck unchecked checkbox Auto-scroll if head unpinned. Turn off View > Show Clipping while recording. Minimize the Audacity window whenever you have no need to see it.
  • Turn off Transport > Transport Options > Software Playthrough (on/off) unless it is essential you hear what is being recorded.
  • Increase the default "Buffer length" setting of 100 milliseconds in Devices Preferences.

On Mac using Mavericks or later, it may be necessary to reduce audio to buffer, possibly to zero.

  • Reduce the amount of audio data being written: Choose 16-bit Sample Format in Quality Preferences and set recording channels to mono in Device Toolbar (unless you need stereo). Either of these actions halves the amount of data Audacity otherwise has to write. A single instrument or solo vocal should usually be recorded in mono and can be panned in the stereo field later using Audio Track Dropdown Menu.
  • Use a local drive with sufficient space: Set the path to the Audacity temporary directory to a local hard drive because these are usually faster than external USB drives. Choose the local drive with the most space. Audacity tells you how much longer you can record for (based on available disk space) in the Status Bar at the bottom of the window.

Computer and hardware

There are many possible actions you can take. Some may have no effect on a skipping problem, others may have a cumulative beneficial effect, so try them all.

  • Quit as many other other applications or processes as possible. In particular, stop anti-virus applications scanning the Audacity Temporary Directory. Disconnect from the internet.
  • On Windows, regularly defragment your hard disk drive (this should happen automatically on Windows, but do not schedule defragmentation during a recording). Disable Windows Update while recording. Consider creating hardware or software profiles that load only essential hardware and services for a recording session.
  • Set Audacity to a higher priority in the operating system.
  • If you are using a USB recording device. connect directly to a USB port, not a hub.
  • Whatever the audio device, ensure it has the latest drivers as supplied by the motherboard or device manufacturer (as appropriate).
  • A faster processor or more RAM could help solve the problem.
  • Set DMA mode for the hard drive on Windows and Linux, hardware acceleration for the video card and avoid sound card interrupt sharing.

 

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