How can I create a custom alert sound in Mountain Lion?

Question

I want to use a personal sound file (currently an mp3) instead of the system alert sounds (sosumi, basso, etc.)

I remember this being really easy on Macs a couple of decades ago, but can't figure out how to do so today.

Answer 1

You need add the sound file to /System/Library/Sounds/, or ~/Library/Sounds. (If you don't know how to locate that easily, you can search for "sosumi", and follow the breadcrumbs at the bottom of the finder window.)

The sound file needs to be converted to AIFF or WAV format. Macworld has a good writeup on how to do this using iTunes or garageband.

Then, in System Preferences->Sound->Sound Effects, it will show up as an option for your system alerts.

Answer 2

It is still easy!. (Mountain Lion)

To create an alert sound

• I just used Qucktime Player to open an mp3 from iTunes.
• Selected a 25 second portion and copied it
• Opened a new Quicktime file and pasted the portion
• Exported as a .Wav file.
• Put the file in ~/Library/Sounds

To use an alert sound

• Opened up the System Preferences->Sounds
• Selected the Effects Tab.
• Scrolled down to my file and selected it.

The play limit appears to be under 30 seconds. That is why I used a 25 second file.

UPDATE

Ok I forgot I have Quicktime Pro (v7)

In QuickTime X.

After Trimming in QuickTime X.

•   Export the file using the Export..  menu.
•   Set the Format to: Audio only.

This will give you a m4a file.

•   Open it in a free app like VLC.

You can drag and drop it on to VLC.

In VLC:

•   Go to the menu : file-> Streaming/Export Wizard..
•   Select: Transcode/Save to file.
•   Hit Next
•   Select: Existing Playlist item. Select the m4a in the list.
•   Hit Next
•   Check the box: Transcode audio.
•   Select the Codec: Uncompressed integer.  (smaller file the float)

•   set or leave Bitrate at: 192.
•   Hit Next
•   WAV should be the only option selected. 
•   Hit Next
•   Hit the  Choose button.
•   give the file a name in the Save As: and choose where to save it.
•   Hit Save.
•   Hit Next.
•   Hit finnish.

The file should now be exported as a .wav