On the Mac, Apple has long made it relatively easy to plug in and immediately use audio inputs, like microphones and headsets. But Mac OS X has almost no built-in support for mixing different audio sources, which provided a perfect opening for Audio Hijack from Rogue Amoeba. It’s a workflow tool for audio inputs and outputs that enables you to combine and separate sources, set timers to record audio at specific times or at recurring intervals, and add effects and filters.
The just-released Audio Hijack 3 extends and improves the software, including a radical overhaul of its interface and methods of pulling together different audio elements. It also adds new options for manipulating settings and listening to audio as it’s being captured.
Rogue Amoeba has decided on a single edition release, which is now called simply “Audio Hijack” — it offers no fewer features than its former “Pro” version, but the name is no longer suffixed with that word. A fully functional version can be downloaded and used for recording up to 10 minutes of audio, after which noise is overlaid. A new copy costs $49 (with a 20 percent discount for TidBITS members), but Rogue Amoeba is offering a $25 upgrade to owners of any previous version. Note that Audio Hijack 3 requires OS X 10.9 Mavericks or later.
You can turn to Audio Hijack any time you need to capture audio. This could be for a recording session, whether live or for a podcast; to grab a broadcast Internet radio session to time-shift; or for recording the outputs of DVDs, webinars, other real-time events, or digital-rights managed media.
Users of previous versions will need to wrap their heads around the new approach because of how distinctly different it is. Veteran hijackers may miss the left-hand navigation bar that compactly listed all of the available input-source workflows; the new display uses spatial and iconographic displays, which may take getting used to.
The Basics of Hijacking — Audio Hijack’s name comes from its basic function: “hijacking,” or taking over, audio streams on a Mac. In previous releases, the input source was the commanding factor. You would set Audio Hijack Pro to grab the sound from a microphone, an app, or a virtual device. Each of these inputs was a separate entry, and could be scheduled, saved to a file, and passed through effects.
This was useful for simple situations, but at one point I had four different input items configured for recording Skype calls, in which I routed multiple sources to a single virtual input, and from there to a file. It was tweaky to use, requiring that I start four separate “hijacking” sessions but record only one.
In Audio Hijack 3’s new conceptual scheme, a session lets you combine multiple inputs, multiple recordings, and multiple outputs in a drag-and-drop layout. Each item has its own controls. This makes typical activities dramatically easier, while also revealing much more of what’s going on at a glance.
This revision also builds in live interaction, allowing changes to many parameters of an active session. One significant new feature lets you pause, rewind, and step through live audio without interrupting the recording. Serenity Caldwell wrote a how-to on this feature for iMore.
Audio Hijack still divvies up inputs into Application, Input Device, and System Audio. Any USB-connected or other available audio source appears as an option for Input Device. With Instant On installed (choose Audio Hijack > Install Extras), applications can have their audio re-routed without being relaunched, which is otherwise required. (Installing the free Soundflower virtual audio device lets you collect and route outputs from multiple sources, too, though it’s not as necessary in this new release.)
Outputs include devices like speakers, Soundflower, headphones, and Recorder — the last of which lets you capture the resulting audio to a file. What’s fantastic in Audio Hijack 3 is that you can have multiple recorders in the same session, recording in different ways, while also having multiple sessions operating at once.
There’s also the option to insert effects along the way, which can include boosting the volume, equalizing bands of sound frequencies, and cleaning up audio. While recording, animation lights up all active audio paths, letting you see precisely the flow of audio from and to devices.
That’s a dry explanation; the program is best explained through use cases.
Make a Scheduled Recording — Audio Hijack now divides its main window into Sessions, Recordings, and Schedule. Sessions holds the sound workflow layouts discussed above. Recordings are where you find the output of Recording items. And Schedules is where you set timed events.
You may have to hunt for these feeds, although you can extract them if they’re listed in the Internet Radio section of iTunes. In iTunes 12, click the three dots in the upper left and choose Internet Radio. Select the desired station, and then press Command-I. Control-click the Location field and choose Copy Path. For public-radio programs, consult PublicRadioFan, which has an extensive listing of feeds and schedules.
After determining that the stream will play automatically in a Web browser, create the full capture sequence in a session, starting with a template, as I describe next. You can watch a screencast of this sequence, too. (Note that you can capture only one stream per browser, but if you have multiple browsers, you could conceivably capture simultaneous audio programs.)
- In the Sessions tab of the Home window, click New Session.
Select Application Audio and click Choose.
In the session that’s created, click the Application source, and then choose Safari from the pop-up menu and paste in the URL.
If you want to change to a different audio recording format than the default (256 Kbps MP3), click the Recorder output, and choose a format from the Recording Format menu, which includes a number of presets that can be customized. You can also set the name of the recording, set tags, and choose a destination other than the default.
Test the playback by choosing Control > Turn Recording Off, and then clicking the Record button. (This prevents writing a file to disk when testing the workflow.) If the browser isn’t open, it will launch it, open the URL, and start recording.
If all goes well, click the Record button again to stop recording, and choose Control > Turn Recording On. (For sessions with multiple Recorders, the item changes to Turn All Recordings Off or On.)
You probably don’t want the Output Device to play during a timed recording: click it and then flip the active switch to Off, or Control-click it and choose Delete Block. (You don’t need to mute the system audio either way, because Audio Hijack captures the application’s sound output before it reaches your speakers.)
Now you should name the session. Unfortunately, there’s no way to name a session from within the Session window. Switch to the Sessions tab, find the session you just created by its default name, click the name, and after a moment it highlights. Name it something descriptive.
Click the Schedule tab and find your session. (You can also click Schedule within the Session window, and it opens Schedule with that item selected.)
Click Add Timer, and set your parameters, such as On Date (one time) or Repeat Every. Remember to figure out the time zone of the recording for live broadcasts outside your area.
You probably want to select Quit Sources When Done to avoid the audio continuously streaming when you don’t need it.
Now you have a timer set. Each schedule can have multiple timers. Just click Add Timer to set additional one-time or repeating scheduled recordings.
Whenever you visit the Schedule tab, you’ll see a list in order of active timers, followed by expired timers, followed by all sessions to which no timers have been attached.
Record a Multi-Input Podcast — My most frequent use of Audio Hijack is recording podcasts in which there are local and remote people involved. I opt for the belt, suspenders, and duct-tape method so that I have fallback positions in case a recording fails. I typically record multi-enders, in which every party records her or his audio locally, which I mix together later. (Jason Snell wrote a thorough rundown of his methods, including multi-enders, at Six Colors.)
But even when everyone is recording locally, I like to have two backups. In Audio Hijack Pro, I recorded the VoIP program (almost always Skype) and used QuickTime Player to record directly from my mic. With the new version of Audio Hijack, I can now do both.
For a regular VoIP recording, the default template (called Voice Chat) provided in Audio Hijack is quite good. Let me break down what the template does:
- Audio Hijack captures audio from Skype (parties on the other end of the conversation) and from your microphone. The Split Between Channels option puts your audio inputs on the left channel and the application’s output on the right. This provides both ends of the call. (A single mic is almost always mono, so you’re not losing stereo sound.)
The VU Meters give you a visual representation as sound is recording. If you click the meters icon, a larger and better labeled sound meter appears. (You can also drag in a Menu Bar Meters item from the library at the bottom right, and see the live levels in your menu bar.)
Audio Hijack now captures the audio in two ways. At the top, a Recorder writes the left and right channels to a stereo MP3. At the bottom, the right channel (the application’s output) is routed to an Output Device. This prevents an echo where you would hear your own audio in the output.
For more complicated podcast recordings that I don’t necessarily plan to edit, I take three audio sources: the Skype output, a mic, and Soundflower, after setting a sound-effects program to route itself through Soundflower. To have a high-quality backup recording of each source, I first route them through uncompressed AIFF Recorder items.
To avoid an echo, I route the Skype and Soundflower audio into an Output Device, and then the mic and the Output Device into a meter display and onward into a mono 128 Kbps AAC file. If my recording goes perfectly, I may be able to use the prefixed AAC file. If not, I can take my uncompressed audio sources and fiddle with them.
For a podcast that I plan to edit, I would omit the final mixed-down AAC, and record all three inputs only to a high-quality AAC (256 Kbps) or AIFF file.
Jack Me In, Bob — Audio Hijack 3 has myriad other changes, and a host of features that would require another article of this length to cover. Here are just a few additional highlights.
- For previous users, the Hijack and Mute buttons are gone, and the Recording and Split buttons have migrated. You can’t listen to audio without recording, but you can choose Control > Turn Recording Off to effect the same result. Split, where one file is closed and another opened, is now available in every Recorder item (click the Split button on the item’s icon, or click the item and then click Split Recording) or globally as Control > Split Recording.
A new Overdrive feature is available via the Volume built-in effect. Drag that into a workflow, and you can boost the input volumes by two-, three-, or fourfold.
Recordings are now organized by session, rather than in a long list. If you want to delete one, choose Edit > Delete (Command-Delete). Hover over a recording and you’ll see a magnifying glass that, when clicked, shows the recording in the Finder. There’s currently no way to open the recording directly in a sound-editing app like Rogue Amoeba’s own Fission. That will undoubtedly change soon. Also missing from Audio Hijack Pro is the option to run an AppleScript after a recording finishes.
The app is highly interactive. You can remove and add elements, change input sources, and turn on and off elements (effectively muting them) without missing a literal beat.
It will take me weeks, maybe months, to plumb the depths of Audio Hijack 3, as I revise old workflows and set up new projects that formerly required other software or that I found infeasible in its predecessor. This refresh of the app isn’t skin deep: it goes down into the inner workings. It will take veteran users some getting used to, but the advantages for old and new users are clear: more power, great flexibility, and less work for better results.