Rogue Amoeba’s Audio Hijack Pro is a terrific program for capturing audio that plays through your Mac but it’s an incomplete solution—once you’ve captured hours of streaming audio, there’s no way to split it into digestible segments and then identify which bit is which. Rogue Amoeba fills in that missing functionality with Fission 1.1.1, an audio editor that makes dividing long audio files into individual tracks as easy as possible.
Fission isn’t intended to be a full-featured two-track audio editor as is Freeverse’s $80
Sound Studio 3
or HairerSoft’s $30 Amadeus II (
; “Best of Mac Gems”,
). Unlike these other applications, you can’t record audio directly into the program. Rather, it takes files you’ve already recorded, displays them as wave forms, and then provides the tools for automatically splitting audio streams—for example, Internet radio broadcasts or LPs and cassettes that you’ve captured with a program like Audio Hijack that you’d like to turn into iTunes tracks or cell phone ring tones. Unlike some other audio editors that convert files as they’re imported or saved, Fission lets you edit and save the edited files in their native audio format—the program supports MP3, AAC, Apple Lossless, AIFF, and WAVE. Thus, there’s no loss of audio quality that can occur when you convert a file.
You use the program’s Smart Split command to manipulate your audio file. Select the command and up pops the Smart Split window. You can choose one of the two presets—Analog Recording or Digital Recording—and the file is marked with green lines where Fission senses that gaps between tracks exist. If it fails to find all the gaps (or finds too many), simply adjust a couple of sliders. The first slider is Length, which tells Fission how long a period of silence must be to be identified as a gap. (The default is 2 seconds.) The other is Sensitivity, a setting that determines gaps by how quiet the music gets. (The default for the Digital Recording preset is -60 dB.) You can save these adjustments as presets. Once you’re happy with the split points, just click the Split button and the file is divided into individual tracks.
In several test recordings I was able to use these sliders to accurately identify every track, but if the sliders fail, you can manually insert splits using the program’s Split tool. I never had this kind of luck with Roxio’s CD Spin Doctor 2, a utility included with
) that’s also designed to automatically split long files. What’s more, unlike Fission, CD Spin Doctor did not import AAC and MP3 files.
Fission offers some other basic editing features. For example, a click of a button cuts, cuts and splits, or crops a selected audio track. You can also click buttons to fade-in or fade-out selected audio—the beginning or end of a track, for example. Fission lets you scrub audio by dragging the playhead back or forward while audio plays. And if you’d like to mark split points by time—half an hour into the file, for instance—you can do that as well.
Fission allows you to tag tracks within the program via its Inspector pane. This is a really useful feature, letting you enter typical ID3 tags—title, artist, album, track number, and genre, for example, as well as lyrics and artwork—before you export the individual files.
Much as I appreciate this feature, I wish the Inspector were a little more refined. As it is, you can enter Artist and Album information before splitting the track and that information is inherited by the split tracks. But it doesn’t also automatically enter track numbers—which would be helpful when you’ve split a single album and would like iTunes to eventually play the tracks in the proper order. You can set track numbers manually in Fission or later in iTunes, but it’s a bother. Also, moving from track to track and field to field requires a lot of mousing. Next and Previous track buttons (with accompanying keyboard commands) would be welcome, as would fields (such as Title) that stayed selected as you move from one track to another.
Macworld’s buying advice
Fission is the best tool I’ve found for identifying gaps in a variety of audio files and splitting those files into individual tracks. Its ability to edit files in their native format is a godsend (and a feature I’d like to see added to other audio editors). While tagging files within the program is useful, I’ll keep my fingers crossed that in Fission’s next revision, it will be as easy as it is useful.
’s Senior Editor Christopher Breen is the author of
The iPod and iTunes Pocket Guide, second edition
(Peachpit Press; 2007).
Fission’s Smart Split feature allows you to easily divide audio streams into individual tracks.