Unify's built-in Audio File Player plug-in is a very simple streaming audio player. It can play most types of audio files (WAV, AIF, MP3, etc.), and because it plays direct from disk (with minimal RAM buffering), it can play files of any length.

The Audio File Player has three main uses:

1. To play full-length backing tracks or stems.
2. To play shorter drum loops.
3. To feed short or long audio segments into a vocoder-type plug-in such as the bundled mda Vocoder.

For the first two uses, the Audio File Player will most often be used in the instrument slot of an INST layer, although the present version is not technically an instrument because it does not respond to MIDI. (It simply plays when the Transport is running.) For any use, Audio File Player instances can be used inside a ComboBox.

Audio File Player's GUI is very simple, featuring just three controls:

The Library Menu on the left facilitates choosing audio files inside the Audio Files sub-folder of a Unify library folder. Simply select the desired library and click the file button on the right, and Unify will automatically open the correct folder.

• The first entry in the pop-up menu is always “[no library]”. If this is selected, Unify will attempt to open the Audio Files folder inside the main Unify data folder; if there isn't one, it will start in the main Unify data folder itself.

The file button displays the name of the currently-selected audio file, if there is one, or the text “Click to load audio file…” if none has yet been selected.

The Loop playback checkbox determines whether the file is to be played once, from beginning to end, or continuously, looping back to the start each time the end is reached.

The Play mode pop-up menu allows you to choose what starts the playback:

• MIDI start/stop is the default mode. Playback starts when Audio File Player receives a MIDI note-on, and stops when no MIDI notes are on, i.e., the player has seen a MIDI note-off event corresponding to every note-on effect it has seen (or in non-loop mode, when end of file is reached).
• Sync to Transport means that MIDI is ignored, and the playback simply follows the Unify Transport. When the Transport playhead runs, it plays; when the playhead stops, it stops; when the playhead is re-positioned or rewound, it automatically advances to the appropriate time point.

MIDI-triggered playback is very most useful for one-shot samples and for playing e.g. vocal or drum sounds through the a vocoder effect; see Using with a Vocoder below.

Transport-synced playback is primarily intended for Playing backing tracks or stems below.

Hence, when using the Audio File Player, it's important to set up the Unify Transport correctly.

When you save a Unify patch with instances of Audio File Player, the saved state-data for each instance must include the path to the file to be played. Audio File Player (and other plug-ins including Guru Sampler and MIDIBox) uses the notion of library-relative file paths, to ensure that patches created on one system will play correctly on others.

These plug-ins all support three distinct kinds of file paths:

1. Library-relative: You select a Unify library, and the audio file is found in an Audio Files folder inside that library folder. This is the most “portable” approach, and is the only kind of path used in Unify library patches.
2. Unify-relative: If you don't select any library, but instead leave the library menu set at “[no library]”, Unify will expect the audio file to be found in an Audio Files folder in the main Unify data folder (beside Libraries and Presets). This approach is semi-portable, because if you share a patch using such a path with someone else, they just have to put the audio file into that top-level Audio Files folder.
3. Absolute: When you click the file button, you'll see an ordinary file-select dialog, initially pointing at an Audio Files folder as just described, but you're free to navigate to and choose any file anywhere on your system. If you choose a file outside the Audio Files folder, Audio File Player will save the full, or “absolute” file path. Patches saved using absolute paths will usually not work correctly on other computers, because they will be looking for those very specific file locations, which are probably only valid on your computer.

If you want to play along with a single stereo backing track, create an INST layer using Audio File Player in the instrument slot, and load your backing track into it, then be sure to set Unify's Transport to either “Manual start/stop” or “MIDI / manual stop”. Audio File Player follows the Transport, so in the default “MIDI / Quick Stop” mode, your audio file would only play while you're holding down MIDI notes—not very useful.

• Manual start/stop requires you to click the Play (triangle) button on the Transport to start playback. This can be very useful if your backing track includes some kind of count-in or introduction.
• MIDI / manual stop is similar, but playback will start as soon as you hit the first note on your MIDI keyboard, and then simply continue.

In some cases you may have a whole set of audio files that are meant to be played together at the same time. These are commonly called “stems”, and are used extensively in modern church music. A full set of stems might include all the parts for a complete performance, and you would load only the ones your ensemble can't cover. Working with stems is exactly like working with a single backing track, except that you create one INST layer for each stem track, and then since all Audio File Player instances follow the Transport, they all play, stop, and rewind together.

Checking the Loop playback checkbox causes Audio File Player to loop back to the beginning of the file right after it gets to the end. This can be used in two ways.

For solo practice with a backing track, you may want to loop the backing audio so you can practice a given section over and over. In this case you'd typically set the Transport to “Manual start/stop”, and rather than using a full-song audio file, you'd use your DAW or some other kind of audio editor program to isolate the section you want to work on and export that as a shorter audio file for looping.

To work with shorter, rhythmic audio loops, such as drum loops, you would use the same basic technique with two small alterations:

1. You must ensure that the length of the audio file is an exact multiple of the length of a measure at your chosen tempo. Professionally-prepared audio loops are carefully crafted to ensure this. If you want to achieve similar results with your own files, you'll need to calculate the exact length you need in samples, and trim the file to that exact length.
2. You might want to set the Transport to MIDI / Restart. This causes the Transport to start over from the beginning every time you play the first MIDI note after an all-notes-off condition. This would allow you to control how many measures get played, dynamically based on how you play the keyboard, and gives you the ability to restart the loop any time you need, in case you get out of sync.

The MIDI / Restart method works best for Split patches with a mono bass in the left hand. By setting the key-range of the Transport the same as the left-hand INST layer(s), you will be able to play whatever you like in the right hand, without restarting the Transport.

Audio File Player can be useful as a modulation-input source for a vocoder such as mda Vocoder. The “Arrival - 0 - Welcome to Unify” patch included in the Unify Standard Library (v1.2 update) illustrates some techniques.

Refer to the ComboBox page for more details.