|Tip 402||Tell Your Mac to Do Things|
We can file this tip under “innovative features introduced some time ago.”
Your Mac has powerful speech recognition software, which you might already know about. What you might not know about is a different kind of speech recognition on offer that lets you issue commands to your Mac to do things like start apps or select options within dialog boxes. For this to work, you’ll need a Mac with a built-in microphone, although all modern portable Macs and iMacs have this.
Activating Spoken Commands
To activate spoken commands, open System Preferences (Apple menu→System Preferences), and click the Accessibility icon. Then click the Speakable Items icon in the list on the left, ensure the Settings tab is selected, and click the On radio button next to the Speakable Items heading.
A new circular floating window will appear at the top right of the desktop, which lets you know that your Mac is waiting for voice input. All you need to do is hold down Esc and speak a command, releasing Esc when you’ve finished.
To learn what commands you can speak, hold down Esc and say “Open speech commands window.” This should then show a pop-up window displaying all the commands recognized by default. You can also use Finder to browse to ~/Library/Speech/Speakable Items (open Finder, hit Shift+Command+G, and type the path into the dialog box before clicking Go). Any files you see there relate to commands you can issue—a file called Quit this application means that you can issue that command.
Calibrating the Microphone
It’s very likely you’ll need to calibrate the microphone to get the best results. To do this, click the Calibrate button in the Speakable Items pane within System Preferences; in the window that appears, drag the slider beneath the audio meter to around 25 percent. Then try speaking some of the test phrases listed on the left of the window. They’ll flash if they’ve been recognized, and you’ll hear a “squip” sound. If none seems to work or the results are spotty, try dragging the slider to the left or to the right. Note that on the MacBook Pro I used for testing, I had to drag the slider to the very first bar near the Low heading to get consistently accurate speech recognition, despite the audio meter display appearing to show a perfectly acceptable input at higher settings. See Figure 59, Calibrating speech recognition.
Try saying, “Tell me a joke.” OS X knows quite a few jokes, so try it several times.