Fission is an audio editor designed with simplicity in mind. With it, you can quickly and easily trim and split audio files, all with no quality loss. You can also export from one format to another, batch convert a group of files, and even create iPhone ringtones. Fission makes audio editing simple, fast, and affordable.

Getting Started

This manual provides you with a useful overview of the application, including an outline of the interface, as well as details on using the application. We recommend a quick read-through, but you can also just dive in if you like. Refer back here for assistance at any time, right from Fission's Help menu.

Additional Assistance

The following resources will supplement a read-through of the manual and help you get the answers you need.

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Search This Manual

Use the search field in the upper right to locate specific keywords in this manual.

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Visit Our Online Support Center

Our searchable Fission Support Center provides answers to common questions, as well as tutorials, tricks, and more.

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Email Support

Finally, Rogue Amoeba's top-notch Support team is always ready to assist, both before and after purchase. Select Contact Support in the Help menu to get in touch. We're amazingly responsive, and strive to reply within 24 hours.

Information for Users of Previous Versions

If you've used any previous version of Fission, the additional information below may be helpful.

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Release Notes

The Release Notes window always provides a comprehensive list of improvements and fixes made to Fission. Access it from the Help menu.

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Upgrading to Fission 2

If you purchased a license for Fission 1, you're eligible for a heavily discounted upgrade to Fission 2.

Using Fission

Get started with details on the main Fission controls, as well as its basic functionality.

Fission's Editing Window

Fission's Editing Window
Fission's Editing Window

Fission's editing window contains all the controls for editing audio. Here, audio can be selected and removed, split points can be added, and volume levels can be adjusted. For more details, see all the pages in the “Editing Operations” section.

Fission's Inspector


Fission's Inspector

When an audio file is open, the Inspector can be shown on the right side of the window. Here, metadata can be updated, including ID3 tags, lyrics, and artwork. Information on the file, including bitrate, sample rate, and more, can also be found under the Summary tab.

Fission's Batch Converter


Fission's Batch Converter

Fission's Batch Converter makes it a snap to convert between audio formats. Drop as many audio files as you like onto the Batch Converter, then select the format to which you'd like to convert them. Click Convert, and Fission does the rest. Learn more on the Converting Formats page.

Removing and Adding Audio

Fission can be used to remove audio from a file, as well as add new audio.

Deleting Audio

Deleting audio is as easy as selecting and removing it. First, select the exact audio you wish to remove. You can tweak your selection by dragging either edge to increase or decrease the length. Alternately, the Set Selection option in the Tools menu will let you select an exact length of audio.


A selection of audio to be removed

Once the audio is selected, you can delete it by clicking the Remove button in the toolbar, or by selecting Remove from the Clip menu. The selected audio will then be removed from the file. If you wish to automatically add fades into and out of the removed point, turn on the Fade Around Removed Audio option in the Clip menu. For more details on fading, see the Fades and Volume Adjustments page for details.


Remove & Split button

You can also use the Remove and Split function in the Toolbar or Clip menu, to add a split point between two pieces of audio. For more on split points, see the Splitting Audio page.

Cropping Audio

Cropping audio is also very straightforward. First, select the audio you wish to keep. Remember that you can tweak a selection by dragging either edge to increase or decrease the length, or set an exact selection with the Set Selection option in the Tools menu.


The Crop Button

Once the exact selection is made, the audio can be cropped by clicking the Crop button in the toolbar, or choosing Crop from the Clip menu. All other audio will be removed, leaving you with only the selected audio.

Adding Audio

Audio can be added to a file in two ways. First, if you wish to simply join two (or more) files together, you can drag and drop a file from the Finder into an already-open audio file. The second file will be added to either the beginning or end of the open file (depending on where you drop) as a separate clip, so that it can be easily moved and manipulated. To merge the two clips together, just highlight the split point separating them, and delete it.

File's being joined
Two files can easily be joined into one

Audio can also be pasted in between audio files. With multiple audio files open, you can select audio from one file and copy it out using the Edit menu. Switch windows to the destination file, and paste it in where desired. The audio will be inserted wherever the playhead is currently located, as a separate clip. Again, to merge the two clips together, just highlight the split point separating them, and delete it.

Inserting Silence

Finally, Fission can add periods of silence to files, with the Insert Silence command. The Insert Silence sheet will appear:

Fissions's Insert Silence Sheet

With the settings seen above, 7.5 seconds of silence will be inserted where the playhead is currently located. Note that silence is added as a separate clip, so that it can be easily moved and manipulated. To merge the silence fully, just highlight the split points and delete them.

Splitting Audio

Fission can help you rapidly split one long audio file into multiple files.

Split Points and Clips

Fission uses split points, or splits, to separate clips in an audio file. When a file contains multiple clips, the split points are what separate each clip. Saving a file with multiple clips results in multiple audio files being saved out.

To adjust the length of a clip, just move the relevant split by clicking and dragging it to the desired point. To merge two clips together, just remove the split point separating them by clicking it to highlight, then pressing the delete key on your keyboard. You can also remove all splits from a file by selecting Clear All Splits from the Edit menu.


A split point between two clips

Adding Split Points

Adding a split point can be done in several ways. Generally, placing the playhead where you wish to split is the first step. You can click once in the main waveform to move the playhead, or simply play the file until the desired point. Once the playhead is in place, you can click the Split button in the Toolbar, or select Split at Playhead from the Clip menu. A split point will be inserted into the file, separating the audio into two distinct clips.

If you know the exact timestamp where you'd like to split, you can also use the Add Split option in the Tools menu to add a precise split.

Removing Split Points

You may wish to remove a split point, to prevent separate files from being saved out. To remove a split point, just click it, then press Delete on your keyboard or choose Delete from the Edit menu. Alternately, you can choose Clear All Splits from the Edit menu to remove all splits at once.

The Smart Split Tool

Fission's Smart Split tool can be used to automatically find split points in a file, based on where there are silences. This can be particularly useful for rapidly splitting up recordings from analog sources like records and tapes, as well as multi-song digital recordings. To access it, select Smart Split from the Tools menu:


Fission's Smart Split Window

Smart Split identifies silences based on the settings selected and shows where it will place split points. When you click the Insert Splits button, the split points will be added to the file, creating multiple clips. If needed, adjust these splits by moving them, adding more, or removing any which are erroneous. Once you've got the split points set, save the audio out and you'll get a distinct file for each clip.

Fades and Volume Adjustments

Fission can fade audio in and out, normalize an entire file, and adjust the gain of a portion of audio.

Fading In or Out

To fade audio, start by selecting the audio you wish to fade. Once a selection is made, click the Fade In or Fade Out buttons to fade the audio across the entire selection.


Fission's Fade Buttons

As well, with the Fade Around Removed Audio option turned on in the Clip menu, you can set Fission to automatically fade around areas where audio has been removed. The duration of these fades can be adjusted in the Preferences window.

Normalizing Audio


Fission's Normalize Button

Normalize increases the gain of the selected audio, so that the loudest sample is at set to the maximum possible value. This makes the selection as loud as possible without causing distortion. To normalize a selection of audio, just highlight the desired audio then click the Normalize button.

Gain Adjustment


Fission's Gain Adjustment Slider

You'll see the Gain Adjustment button at the bottom of any selection. Clicking and holding the button will bring up the Gain Adjustment slider. Just slide up or down to adjust the gain of the selection.

Audio Format Conversion

While originally designed for lossless audio editing, Fission can also save audio between formats in a process known as transcoding. For example, you can edit an AIFF file and save it to MP3, or take a collection of FLAC files and convert them to AAC. Fission offers two ways to convert formats: you can export a single file to a new format, or perform a batch conversion of many files at once.

Fission offers support for saving to MP3, AAC, Apple Lossless, FLAC, AIFF, and WAV, with defaults offering varying quality levels. Audio experts can even customize all settings using the Custom menu option. Remember that higher bitrates provide higher quality, but also create bigger files. For more details, see the Audio Formats Overview page.

Exporting

When you've got an audio file open, selecting Export from the File menu will bring up this sheet:

From this sheet, you can export a file to your desired format and Fission will save it out in seconds. You can also export just a selection of a file, with the Export Selection option.

The Batch Converter

Fission's Batch Converter makes it easy to transcode multiple files at once. The Batch Converter can be opened from Fission's Start window, or by selecting Show Batch Converter from the Window menu.

In the Batch Converter window, you can add multiple files to the table at the top, then select the desired format and output location. Once that's set, clicking Convert will cause the files to be converted in sequence.

Making Custom iPhone Ringtones

iOS devices allow you to set custom tones to play when you receive a phone call or text message, as well as when an alarm or timer goes off. With custom tones, you can assign specific sounds or music to individuals, so you can tell who's calling or texting without even looking at your phone. You can even pick music to wake up to — rise and shine with your favorite song, or force yourself out of bed with music you despise.

Fission enables you to transform any audio file into a tone for use on any iOS device. While these custom tones are often referred to as “iPhone ringtones”, they work great with the iPad and iPod Touch as well.


A custom tone, cropped and ready for saving

The process for making custom tones has varied in recent years, due to changes made by Apple, but Fission has always kept up. For current details, please see the support Knowledge Base article on our website.

Making Chapterized Files

Fission has support for saving chapterized AAC and chapterized MP3 files. These are audio files which contain distinct sections, known as chapters. Chapterized files are often used by podcasters to make enhanced podcasts.


A Chapterized AAC file in iTunes

Visit our support Knowledge Base to read a detailed article on making chapterized files with Fission.

An Overview of Audio Formats

Fission has native support for editing six of the most popular audio formats: MP3, AAC, Apple Lossless, FLAC, AIFF, and WAV. Editing of these formats with Fission is always done losslessly.

Fission also has support for a large number of less common formats. Our online Knowledge Base provides a current list of supported formats.

Selecting an Audio Format

First, if you're unsure what audio format to save to, MP3 is likely a very safe bet. It will provide a very small audio file which can be played almost anywhere.

If you don't want to lose any quality but still wish to save disk space or bandwidth when transferring the file, Apple Lossless is a good choice for use with Apple devices. For lossless files which will play anywhere, AIFF or WAV are your best options.

Finally, if you can avoid switching audio formats entirely (by simply saving, instead of exporting), you'll prevent quality loss from occurring. That said, transcoding between formats is certainly fine when a specific file format is required, and quality loss caused by transcoding is generally not problematic.

For more information on each specific audio format, read below.

MP3

MP3 iconMP3 is the most popular format for audio compression, making it the most universal file type; MP3 files can be played almost anywhere. MP3 files are compressed lossily, meaning some audio quality may be lost when they're created. However, the files are also very compact, using only a small amount of disk space.

The Variable Bit Rate (VBR) option for MP3 files allows the software to dynamically adjust the bitrate of the encoding, saving disk space without causing additional quality loss. Modern MP3 encoding is largely done with VBR.

AAC

AAC iconThough not as universal as MP3, AAC is another well-known format for audio compression, popularized by Apple. As such, AAC files play well on the Mac and iOS devices, but may not be as easy to play elsewhere. Like MP3, AAC files are compressed lossily, meaning some audio quality may be lost when they're created. AAC files are generally even more compact than MP3, using less disk space for the same level of quality.

The High-Efficiency (HE-AAC) option for AAC files allows the software to compress encoding even further, to save disk space without additional quality loss. HE-AAC is limited to low bitrates (24 - 80 kbps) and a compatible player is needed to play the audio back optimally.

Apple Lossless

ALAC iconAs you might expect, the Apple Lossless format was created by Apple. It's a lossless compression format, which means that even though the files are shrunk down in size, no audio quality is lost. Though they are compressed to around half the size of uncompressed AIFF/WAV files, these files will still be quite large. They'll play on all iOS devices and in iTunes, as well as in many applications on the Mac.

FLAC

FLAC iconFLAC is an open competitor to Apple Lossless. Like Apple Lossless, it offers lossless compression, creating large files of around half the size of uncompressed AIFF/WAV files but losing no quality. FLAC is a popular format for web distribution of lossless audio. Unfortunately, playback of FLAC files is not as well supported as other formats. Fission makes it easy to convert files out of the FLAC format, if you desire.

AIFF/WAV

AIFF iconWAV iconAIFF and WAV are twin uncompressed audio formats, which generally work identically. While AIFF was once used largely on the Mac platform and WAV used largely on Windows, they're now each compatible on both platforms. These files have no compression, so they're enormously large, but as with Apple Lossless and FLAC, no quality is lost. AIFF and WAV files will play in almost any audio player.

Preferences

Fission's preferences can be accessed from the Fission menu.


Fission's Preferences window

Audio Settings

Fade around removed audio: This setting adjusts the length of audio automatically faded in and out when removing a section of audio from a file, when the Fade Around Removed Audio option in the Clip menu is on. The time length of fades can be adjusted with this preference. To prevent automatic fades altogether, turn the Fade Around Removed Audio menu option off.

Play audio through: Adjust this to change the output device through which audio from Fission plays.

Audio Scrubbing: When this setting is active, audio near the playhead will be heard as the playhead is moved.

Appearance

Theme Selector: This setting dictates how Fission will appear. The Dark theme is perfect for use in darkened spaces like theaters, while the Light theme is designed for brighter spaces. Of course, either can be used in any setting, according to your taste.

The default Match System setting will follow OS-wide appearance settings. You can alternately can force Fission to use the Light or Dark theme, regardless of your system-wide settings.




Fission's Dark theme
Fission's Light theme

While this manual uses the Dark theme throughout, you can easily try either theme. Fission will update immediately when you adjust this setting.

The Match System option will follow settings found in the General System Preference. On MacOS 10.14 (Mojave) and higher, it follows the Appearance setting for Light or Dark Mode. On MacOS 10.13 and lower, it follows the Use dark menu bar and Dock setting.

Software Update

Automatically check for software updates: With this option activated, Fission compares itself to the most current version available from our server and alerts you when a new version is available. Leave this on and Fission will help you stay up-to-date.

Purchasing Fission

Quick Link: To buy a license key for Fission, visit our online store.

Why should I buy Fission?

Put simply, you should buy Fission because it isn't free. We provide a free trial, so you can test out the program and all its features before you buy it. It's like test driving a car, for as long as it takes you to decide.

In trial mode, all of Fission's features are available to try, but it won't work for full-time use. During the trial, the quality of audio saved through Fission will be degraded through a series of audio fades.

If you use Fission and find you like it, please purchase a license key - support the software you use and love!

To purchase your license key, just visit https://rogueamoeba.com/store/.

What about upgrades?

If you purchased a license for Fission before April 1st, 2012, you're eligible for a heavily discounted upgrade to Fission 2.

Note: If your license key starts with YELO-, you already own Fission 2 - enjoy!

After Purchase

How do I unlock the full version?

The download of Fission from our site contains both a free trial of the software and the full version. To unlock the full, unlimited version, you just need a valid license key. When you purchase through our store, you'll immediately receive a license key in your browser as well as via email. Simply enter this key into Fission to unlock it.

What's your upgrade policy?

While we don't have a hard and fast upgrade policy, our philosophy regarding paid upgrades is simple: We try to do what's right for you and what's right for us. We've got a great track record, with many years of very satisfied customers.

For more details on free updates and paid upgrades, please see this page.

What's your refund policy?

All Rogue Amoeba products are available to try before you buy. We believe that no customer should have to buy software in order to find out how well it works. Our software can be fully evaluated with no limitations in capabilities, prior to purchase. Customers are strongly encouraged to take advantage of these trials prior to purchase. You may also seek any needed technical support from us - we answer support emails rapidly and responsively for current and potential customers alike.

If you would like a refund, please contact hello@rogueamoeba.com within 14 days of your purchase. Because we cannot recover the license key that was sold, refunds are issued on a case-by-case basis.

Recording Audio

Fission excels at editing existing audio files, but what about recording new files? Whether you need to record audio from a microphone or from an application, Rogue Amoeba has you covered with our own Audio Hijack. All recordings made with Audio Hijack can be edited losslessly in Fission.

Powerful Recording

Audio Hijack Screenshot
Audio Hijack provides powerful audio recording options.

For simple yet powerful recording options, Audio Hijack is the way to go. With Audio Hijack, you can capture from already-running applications, record all System Audio at once, set timed recordings to run when you're not around, record to an enormous variety of recording formats, and more.

Download a free trial right from our site.

Installing & Uninstalling Fission

Installing Fission

As you're reading this manual, it's likely you've already successfully installed Fission. Still, in the interest of being comprehensive, the following is the entirety of the installation procedure for Fission.

Drag Fission from your download folder to the Applications folder, then double-click its icon to begin using it.

Uninstalling Fission

If you wish to remove Fission, we'd certainly like to know why! You can contact us directly to provide feedback. We're always working to improve our products, so don't hesitate to tell us what was missing or didn't work for you.

To remove Fission, just quit the application, then place it in the Trash.

 

Fission Rights and Restrictions

Distribution

Unless explicitly stated in writing, Rogue Amoeba Software does not grant permission to sell Fission ("The Software"). Non-profit distribution of The Software in its trial form is acceptable provided that The Software is not modified in any way, and the complete works of The Software are included in the distribution package. If The Software is to be included in a distribution package, Rogue Amoeba requests but does not require that one complimentary copy of said package be sent to the snail mail address found on our site.

What that said:

Don't sell this software directly for profit. If you want to distribute it, great! Just make sure it's unmodified from the download from our site. If you create a distribution package, it'd be cool if you sent a copy to the address above, though this is not required.

Disclaimer

Fission ("The Software") is provided as is. Rogue Amoeba Software ("The Author") is not responsible for any damage to the user's computer system or data and in no event will The Author, its officers, directors, employees or agents be responsible to the user for any consequential, incidental, or indirect damages (including damages for loss of business profits, business interruption, loss of business information, and the like) arising out of the use or inability to use the The Software, even if The Author has been advised of the possibility of such damages. Because some states do not allow the exclusion or limitation of liability for consequential or incidental damages, the above limitations may not apply to you. Further, the consumer agrees that using this software in any way illegal, or even for the purposes of assessing its viability for illegal usage, is prohibited.

What that said:

Be safe when you use the software. Be aware that it's simply a tool designed to make your life better. Don't use it to do illegal or evil things. If you do, be ready to take responsibility for your own actions.