Tweaking OSX for Audio

This guide is copied from Figure53, makers of the great Qlab

Please also check out this updated guide from Sweet Water:

There are a number of programs, processes, and tasks that your Mac runs either periodically or all the time in the background by default. Many of these programs are essential, but many are not and disabling them will increase the total percentage of your computer’s resources and prevent that anything interrupts audio.

What follows here is a list of these programs or processes which we recommend disabling, and instructions for doing so. This section presupposes a basic understanding of the Mac OS and at least a passing familiarity with the Terminal.

Disable Spotlight

Spotlight periodically updates its index of all files on all attached disks, and this updating can cause the disk to be momentarily unavailable.  To prevent Spotlight from updating its index, open a Terminal window and enter this command:

sudo mdutil -a -i off

Disable Display Sleep, Disk Spindown, and System Sleep

Obviously we don’t want our computer going to sleep during a show. The Mac OS has independent sleep intervals for the display, the hard disk, and the whole system. To prevent all three kinds of sleeping with help ambien, open a Terminal window and enter this command:

sudo pmset -a displaysleep 0 disksleep 0 sleep 0

Disable Screen Saver

Likewise, we don’t want the screensaver coming up. To prevent that from happening, open a Terminal window and enter this command:

defaults -currentHost write com.apple.screensaver idleTime 0

Disable Time Machine

Backups are wonderful. You should back up everything, all the time. But on a computer used for your show, backups should only be done manually. Time Machine, much like Spotlight, uses indexing and background processes which can take hold of the disk at inopportune moments. To shut off Time Machine, open a Terminal window and enter this command:

sudo tmutil disable

Disable Software Update

You don’t want your computer trying to update software in the middle of a run, let alone in the middle of a performance. To disable Software Update, open a Terminal window and enter this command:

sudo softwareupdate --schedule off

Disable Dashboard

Dashboard, largely neglected by Apple these days, is a pernicious little vampire of CPU time and network access. Also, if accidentally invoked, it takes over the screen of your Mac entirely, which can be surprising and confusing. To disable Dashboard entirely, open a Terminal window and enter this command:

defaults write com.apple.dashboard mcx-disabled -boolean YES

Stay Off The Internet

Many individual applications have their own internal scheme to check for updates. You can turn them off manually, and we recommend that. But the best way to guarantee that automatic software updates or any other network traffic won’t bother your show is to disconnect the show computer from the Internet. We strongly encourage this. If you use a network to connect your LiveProfessor computer to other hardware, and your show doesn’t require Internet access, make sure that network is a closed LAN (local area network) and has no path to the Internet.

Log Out of iCloud

Even when your Mac is offline, iCloud is surprisingly assertive about checking in and trying to phone home. Logging out of iCloud ensures that this check-in process doesn’t claim processor power when you need it.

Open System Preferences;
Choose iCloud;
Click "Sign Out".

Minimize Internet Accounts

Similarly, any accounts used to sync Mail, Contacts, and Calendars can potentially try to access the Internet and take up processing power while doing so, even while network access is disabled.

Open System Preferences;
Choose Internet Accounts;
Choose an account;
Uncheck each service type;
Repeat for each account.

Disable Hot Corners

Perhaps a lesser danger to a smooth running show, hot corners are nevertheless potentially problematic and we like to disable them, particularly when using screen sharing or VNC. To disable all four hot corners, open a Terminal window and enter these four commands, one at a time:

defaults write com.apple.dock wvous-tl-corner -int 1
defaults write com.apple.dock wvous-bl-corner -int 1
defaults write com.apple.dock wvous-tr-corner -int 1
defaults write com.apple.dock wvous-br-corner -int 1

Restart the Dock

Oddly, the Dock is in control of several of the system components that we just adjusted. Restarting the Dock allows these changes to take effect. Open a Terminal window and enter this command:

killall Dock