An Applescript to cycle the audio input and output sources between two (or more) audio devices

switch_audio.applescript

on alfred_script(q)
    set output_devices to {"Display Audio", "Generic USB Audio Device   "}
    set input_devices to {"Display Audio", "Generic USB Audio Device   "}
    set device_keywords to {"speakers", "headphones"}

    tell application "System Preferences"
        reveal anchor "output" of pane id "com.apple.preference.sound"

        tell application "System Events"
            tell process "System Preferences"
                set target_idx to 0
                if q is not "" then
                    repeat with idx from 1 to count of device_keywords
                        if (item idx of device_keywords is q) then
                            set target_idx to idx
                            exit repeat
                        end if
                    end repeat
                else
                    repeat with idx from 1 to count of output_devices
                        set device to (row 1 of table 1 of scroll area 1 of tab group 1 of window "Sound" whose value of text field 1 is item idx of output_devices)
                        if (selected of device) then
                            if (idx is (count of output_devices)) then
                                set target_idx to 1
                            else
                                set target_idx to idx + 1
                            end if
                            exit repeat
                        end if
                    end repeat
                end if
                if target_idx is not 0 then
                    select (row 1 of table 1 of scroll area 1 of tab group 1 of window "Sound" whose value of text field 1 is item target_idx of output_devices)
                    tell application "System Preferences"
                        reveal anchor "input" of pane id "com.apple.preference.sound"
                    end tell
                    select (row 1 of table 1 of scroll area 1 of tab group 1 of window "Sound" whose value of text field 1 is item target_idx of input_devices)
        			set script_str to "/usr/local/bin/growlnotify --image /System/Library/PreferencePanes/Sound.prefPane/Contents//Resources/SoundPref.icns -name 'Audio switcher' -m 'Switched audio to " & item target_idx of device_keywords & "'"
                    do shell script script_str
                end if
            end tell
        end tell
        quit
    end tell
end alfred_script

As written, it's designed to be used by Alfred. Given the optional parameter it switches to the specified audio source and input. Without the parameter, it picks the next set in the list (which works as a toggle if there are only two items in the list).

The devices in this example match my Thunderbolt Display and my USB sound card. Update the script to suit your own setup. The sound card I have does actually have three spaces at the end of its device name. I have no idea why.

Are you able to share the alfred workflow? i cannot seem to get it to work but could be related to Mavericks.