Activate Surround Sound via MIDI on internal speakers

By default macOS only uses 2 out of our MBXP 4 speakers which sound muffled and are missing a lot of the high frequencies. Enable Surround Sound to get a way better audio experience.

1. As first step, open Audio MIDI Setup from Applications -> Utilities
2. Click on the "+" symbol on the bottom left corner
3. Click Create Muti-Output Device
4. Check both of the Built-in Output options
5. Select the newly created device in the menu bar

Note: there is no default volume control for multi-channel devices in macOS, so in order to change the volume with MBXP audio shortcuts (F5 & F6), you need to get dedicated software.

Here we analyse three options:

• AggregateVolumeMenu (minimal, free & open source)
• Soundflower (free & open source)
• SoundSource (paid app)

AggregateVolumeMenu - How to

Its only purpose is to give you the ability to change the volume of the aggregate sound device you made. It's a very minimal approach avoiding the need of installing a tool where all the sounds flows into it.

How to install AggregateVolumeMenu app on our MBXP? Download it from https://github.com/adaskar/AggregateVolumeMenu

AggregateVolumeMenu code does:

• Get default audio output device for each sub devices of it
• Get or set left and right channel volume.

Here is the gif while popover app to adjust the volume of the aggregate sound device is working

The volume and mute keys (F4, F5 and F6) works as they should.

Credit to Gurhan Polat and @samueljoh

Soundflower - How to

So, how to install Soundflower app on our MBXP? Using brew!

6. Type the following in Terminal app:

brew cask install soundflower

7. Allow it to install a kext from System Preferences -> Security & Privacy
8. Restart the computer (even if you are not prompted to do so...)
9. Now Soundflower should be installed successfully; please choose System Preferences -> Sound
10. Select the Output tab and select "Soundflower (2ch)" from the list, turn the Output volume up

11. In the same panel, choose the Input tab, again select "Soundflower (2ch)" and turn the Input volume up. Then close the System Preferences window.

At this point, you will no longer be able to hear what is playing on your MBXP since the sound output of the computer is being sent to the Soundflower app. To hear what is playing on your machine while using Soundflower, you need to run SoundflowerBed app.

12. Type the following in Terminal app:

brew cask install soundflowerbed

13. Launch SoundflowerBed from Applications and allow its execution from System Preferences -> Security & Privacy: you will see a "flower" menu to the right of your MBXP’s menu bar
14. Click on the "flower" menu: selecting Multi-Output Device will allow you to hear your MBXP’s sound again

Now you have shortcuts working for your audio!

Note: If you think the sound is not loud enough, in the Output tab of Sound panel, select the actual device that would play the sound, e.g., “Internal Speakers”, and turn the Output volume up. Then select back ”Soundflower (2ch)”:

Enjoy your music!

Sidenote

For supporting full auto sleep mode (i.e. macOS default hibernatemode 3) the following additional step is needed:

• setting in macOS menubar Soundflower (2ch) to None as default settings instead of Multi-Output Device (this means that you need to manually set Multi-Output Device when it is necessary)

This additional step is needed since Soundflower maintains an open audio channel even when no audio is playing (for reference see Soundflower prevents screen saver, display and comptuer sleep #179)

Credit to @huotarih and @profzei

SoundSource - How to

• Download and install SoundSource app on our MBXP
• When prompted, install ACE and allow its execution from System Preferences -> Security & Privacy
• Then select Multi-Output Device for Output and Sound Effects tabs in SoundSource System sub-menu

Full auto sleep mode (i.e. macOS default hibernatemode 3) is supported.

Enjoy your music!