Mac and USB input devices

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Revision as of 05:14, 4 December 2010 by BillWharrie (talk | contribs) (some tweaks)
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On Mac OS X and using Audacity 1.3.12 or later, the following procedure should get sound from the USB audio input device into Audacity. This includes USB turntables, USB cassette decks and external USB audio input/output adapters.

1) Connect the USB device directly to a free USB port on your Mac. Do not connect through a USB hub. Turn the device on. If it is a USB turntable or cassette deck, begin playing an LP or cassette. For other USB interfaces, input some sound to the device.

2) Go to Apple Menu > System Preferences then select the Sound preferences panel, then click on the Input tab. In 10.5.8 you will see something like this (it may look slightly different in 10.4 or 10.6)

Select USB Audio Codec from the Input list.

Note that:

  • "The selected device has no input controls" - this means that whatever level the device sends to your Mac is what you get.
  • The blue "Input level" meter is showing that sound is being input.
If there is no indication on the Input level meter, stop now and figure out why. You may need to use Audio Midi Setup to configure the USB device before the Mac will recognize it. See the section below on using Audio Midi Setup.

Assuming you have sound coming into your Mac through the USB device, continue as follows.

3) Start Audacity and go to Audacity > Preferences then the Devices section. In 10.5.8 you will see something like this (it may look slightly different in 10.4 or 10.6)

Under "Recording" make the choices shown.
Note that you do not want to set the Playback Device to your USB device in the case of a USB turntable or cassette deck. In most cases you will want the Playback Device set as shown - this will cause playback to occur through your Mac's built-in speakers.
Click OK to accept the settings.

4) Click on the Transport menu and make sure that "Software Playthrough" is checked.

5) Note that the Input volume slider is greyed out and cannot be used. Remember that "The selected device has no input controls".


6) With the LP or cassette playing, or with sound being input to the USB interface, click on the recording meter to begin monitoring.

  • Make sure that the levels are below 0 dB, and that the clip lights do not come on.
  • Some USB turntables have a volume control somewhere on the turntable. If the levels are too high in Audacity, look on the turntable or in your manual to see if you have a volume control. For external USB audio interfaces, simply turn down the volume of the device that is feeding the USB interface.
Warning icon If you got an indication on the blue System Preferences input level meter in step 2, but do not get any indication on the Audacity input level meter, go to the next section and use Audio Midi Setup to set up your USB device.

7) If you have got this far and are getting a good indication on the recording level meters, you are ready to begin recording!

Using Audio Midi Setup

There are reports that the above procedure will not work with certain USB devices, including some from Logitech. If you still can't get sound into Audacity, continue to set up the USB input device using the Audio Midi Setup program.
You must use Audio Midi Setup if you want to change the bit depth or sample rate of your device.

1) Quit Audacity if necessary.

2) In the Finder, click on Go > Utilities then open "Audio Midi Setup". In 10.5.8 you will see something like this (it may look slightly different in 10.4 or 10.6)

Make the selections as shown.
  • The Format setting of 44100 Hz and 2ch-16bit is standard for most interfaces, and corresponds to the CD data standard.
  • Note that the "Volume" sliders are disabled - as expected, since the selected device has no input controls.

3) Quit Audio Midi Setup, start Audacity and click on Audacity > Preferences then the Quality section. In 10.5.8 you will see something like this (it may look slightly different in 10.4 or 10.6)

Under "Sampling", set "Default Sample Rate" and "Default Sample Format" to match the settings you made in Audio Midi Setup.