Apple Provides Details on Using High-Impedance Headphones With New MacBook Pros

Thursday, October 28, 2021 5:56 AM

Use high-impedance headphones with new MacBook Pro models

Connect high-impedance headphones directly to MacBook Pro (14-inch, 2021) or MacBook Pro (16-inch, 2021).

The 3.5 mm headphone jack on the MacBook Pro (14-inch, 2021) or MacBook Pro (16-inch, 2021) features DC load detection and adaptive voltage output. Your Mac can detect the impedance of the connected device and will adapt its output for low- and high-impedance headphones, as well as for line-level audio devices.

When you connect headphones with an impedance of less than 150 ohms, the headphone jack provides up to 1.25 volts RMS. For headphones with an impedance of 150 to 1k ohms, the headphone jack delivers 3 volts RMS. This may remove the need for an external headphone amplifier.

With impedance detection, adaptive voltage output, and a built-in digital-to-analog converter that supports sample rates of up to 96 kHz, you can enjoy high-fidelity, full-resolution audio directly from the headphone jack on your MacBook Pro.

About high-resolution digital-to-analog conversion on new MacBook Pro models

The hardware digital-to-analog converter (DAC) built into MacBook Pro (14-inch, 2021) and MacBook Pro (16-inch, 2021) supports sample rates of up to 96 kHz. 

MacBook Pro (14-inch, 2021) and MacBook Pro (16-inch, 2021) feature a high-quality built-in hardware DAC that can convert up to 96 kHz digital audio to analog audio. Connect an analog device like headphones or speakers directly to the headphone jack on your Mac and monitor your audio at full resolution without needing an external DAC.

To set the sample rate for the headphone jack, use the Audio Midi Setup app, which is located in the Utilities folder of your Applications folder. Make sure to connect your device to the headphone jack. In the sidebar of Audio MIDI Setup, select External Headphones, then choose a sample rate from the Format pop-up menu. For best results, match the sample rate for the headphone jack with the sample rate of your source material.

Set up audio devices in Audio MIDI Setup on Mac

Use Audio MIDI Setup to set up audio input and output devices, such as microphones and multichannel audio interfaces. You can also use it to route audio from iOS and iPadOS devices directly into your Mac.

Available settings in Audio MIDI Setup depend on the audio device you’re using. For example, you can adjust the volume for each channel your audio output device has available.

The Audio Devices window.

  1. Connect your audio devices to your Mac and, if necessary, install any software included with the devices.

  2. In the Audio MIDI Setup app  on your Mac, in the sidebar of the Audio Devices window, select a device.

    Note: For iOS and iPadOS devices, first click Enable, then select the device. You may be asked to unlock your device with a passcode or to trust the device.

  3. Control-click the device, or click the Configure Selected Device pop-up menu  at the bottom-left of the sidebar, then choose how the device is going to be used:

    • For sound input: Choose Use This Device for Sound Input.

    • For sound output: Choose Use This Device for Sound Output.

    • For playing system sounds: Choose Play Alerts and Sound Effects Through This Device.

  4. On the right side of the Audio Devices window, choose the options available for the device you selected:

    • In most cases, “Clock source” is set to the default.

    • Click the Format pop-up menu, then set the sample rate and bit depth. Make sure they match the appropriate settings for your audio device.

    • If your Mac supports the hardware sample rate converter, the Hardware Rate Converter pop-up menu is available in the Input pane. When you choose Automatic from the pop-up menu, the hardware sample rate converter is turned on if the audio samples coming in are PCM and formatted according to the international standard IEC 60958-3. The hardware sample rate converter is turned off if the input stream is encoded. You can also choose Enable or Disable from the menu, to keep the hardware sample rate converter turned on or off.

    • If software volume control is available for your device, the Volume sliders appear blue to indicate that they’re active. Drag the sliders to set the volume for each channel.

    • To set up a surround (multichannel) speaker configuration, click Configure Speakers, then set up the configuration.

Set up external speakers for stereo or surround sound in Audio MIDI Setup on Mac

You can configure external speakers connected to your audio device for stereo or multichannel output, such as surround sound.

The Audio Devices window showing an aggregate device in the Quadrophonic Isometric View. In the list of streams at the top of the window, a stream with four channels is selected. The 3D view shows the four speakers positioned in the room.

Note: Before you configure the speakers, connect them to your audio devices. Make sure your audio devices have any required software installed, are connected to your Mac, and are turned on.

  1. In the Audio MIDI Setup app  on your Mac, select an audio output device in the list, then click Configure Speakers.

    If your output device has multiple streams, they’re listed at the top of the window.

    To change how you view the speaker configuration, click View, then choose a view. For Isometric or Side view, you can drag the 3D view to rotate it 360 degrees.

  2. Click the Configuration pop-up menu, then choose a configuration, such as Stereo or 5.1 Surround.

    If you have five front speakers and two rear speakers, choose 7.1 Surround. If you have three front speakers and four rear speakers, choose 7.1 Rear Surround.

  3. For each speaker in the list, click the Channel pop-up menu, then choose a channel to assign to the speaker.

    You can click a speaker in the 3D view to highlight it in the list.

    Tip: If your output device has multiple streams offering multiple channels, it may be difficult to find the channel you want in the pop-up menu. At the top of the window, you can deselect the checkbox for each stream you don’t want to use, so their channels aren’t shown in the pop-up menu.

  4. To hear a speaker’s test tone, click its Speaker button .

    For surround sound configurations, make sure the test tone for each speaker is at the same volume when heard from the listener’s vantage point.

    You can adjust the volume for each speaker channel in the Audio Devices window.

    Tip: You can adjust the test tone volume in the Audio pane of Audio MIDI preferences by dragging the slider.

  5. Click Apply to save your configuration and apply it to the speakers.

Some macOS apps render audio output in stereo while others use multichannel, depending on the media content. You may want to set up your speakers for both configurations to customize your audio experience when using apps.