Decrease the volume

`Ctrl` + `↓`

All hotkeys for iTunes 11 for Windows

With full keyboard navigation enabled Click the currently selected control	`⤶ Enter`
Playback Move backward or forward within a song	`Ctrl` + `Alt` + `← →`
Playback Listen to previous or next album in a list	`↑ Shift` + `← →`
With full keyboard navigation enabled Open or close the selected item's disclosure triangle	`← →`
File and window (on the video) Choose artwork for the selected video	`Ctrl` + `Mouse left click`
Library and playlist Create a playlist from a selection of songs	`Ctrl` + `↑ Shift` + `N`
Library and playlist Create a new smart playlist	`Ctrl` + `Alt` + `N`
General Refresh source list	`F5`
iTunes Store Go to next page in the iTunes Store	`Ctrl` + `]`
iTunes Store Go to previous page in the iTunes Store	`Ctrl` + `[`
iTunes Store (after typing in Search field) Initiate a search in the iTunes Store	`↑ Shift` + `⤶ Enter`
iTunes Store Open the Store menu	`Alt` + `S`
File and window In the Get Info window, see the info for the next or previous song in the list	`Alt` + `N`
File and window In the Get Info window, see the info for the next or previous song in the list	`Alt` + `P`
File and window Select the search field	`Ctrl` + `F`
File and window then press the indicated key to use an option (not all visual effects support this)	`?`
File and window Stream audio file at a specific URL to iTunes	`Ctrl` + `U`
General (while opening iTunes) Open iTunes in “safe mode” (without external plug-ins)	`Ctrl` + `↑ Shift`
Spoken word shortcuts Go to last or next chapter (if available)	`Ctrl` + `↑ Shift` + `← →`
File menu Create a new playlist	`Ctrl` + `N`
File menu Add a file to your music library	`Ctrl` + `O`
File menu Close the iTunes window	`Ctrl` + `W`
File menu Open the song or CD Info window for the selected song or CD	`Ctrl` + `I`
File menu Show where a song file is located	`Ctrl` + `R`
File menu Show the currently playing song in the list	`Ctrl` + `L`
Edit menu Open iTunes Preferences	`Ctrl` + `,`
Edit menu Undo your last typing change while still in edit mode	`Ctrl` + `Z`
Edit menu Cut the selected song’s information or artwork	`Ctrl` + `X`
Edit menu Copy the selected song’s information or artwork	`Ctrl` + `C`
Edit menu Paste the selected song’s information or artwork	`Ctrl` + `V`
Edit menu Select all the songs in the list	`Ctrl` + `A`
Edit menu Deselect all the songs in the list	`Ctrl` + `↑ Shift` + `A`
Control menu Start or stop playing the selected song	`Space`
Control menu When a song is playing, play the next song in a list	`→`
Control menu When a song is playing, play the previous song in a list	`←`
Control menu Increase the volume	`Ctrl` + `↑`
Control menu Decrease the volume	`Ctrl` + `↓`
Control menu Mute the sound (song keeps playing)	`Ctrl` + `Alt` + `↓`
Control menu Eject a CD	`Ctrl` + `E`
View menu Switch to the MiniPlayer	`Ctrl` + `↑ Shift` + `M`
View menu Hide or show the Browser (Artist and Album columns)	`Ctrl` + `B`
View menu Turn the visualizer on or off	`Ctrl` + `T`
View menu Switch between viewing visual effects using the entire screen or in the iTunes window (when visualizer is on)	`⌘ Cmd` + `F`
View menu Enter or exit full-screen view	`Ctrl` + `↑ Shift` + `F`
View menu Open the View Options window for the selected source	`Ctrl` + `J`
Help menu Open iTunes help	`Ctrl` + `?`
General Edit the name of the currently selected item	`F2`
General Interrupt the current process (burning a CD, syncing, converting a file, and so on)	`Ctrl` + `Break`
With full keyboard navigation enabled Select the next control	`⭾ Tab`
With full keyboard navigation enabled Open the selected item's disclosure triangle	`+`
With full keyboard navigation enabled Close the selected item's disclosure triangle	`-`