Programmatically launch the Mac's System Preferences screen -> Sound

There is an easier way:

NSURL * url = [NSURL fileURLWithPath:@"/System/Library/PreferencePanes/Speech.prefPane"];
[[NSWorkspace sharedWorkspace] openURL:url];

You can applescript it:

tell application "System Preferences"
    activate
    set the current pane to pane id "com.apple.preference.sound"
    reveal anchor "Output" of pane id "com.apple.preference.sound"
end tell

Adapted from this link.