Learn about the differences between sample-based timing and tick-based timing. Explore how audio and MIDI behave in a tick-based vs. sample-based operation.
- [Instructor] As you start working with Midi in a session, one of the things you will notice is that your Midi and instrument tracks ae tick based by default, whereas your audio tracks are sample based by default. Here, we'll take a look at exactly what this means, and discuss how it can affect your work. I've got a session open to use for illustration purposes, which has both an audio track for drums and an instrument track with a Midi drum part. I've also included a click track for reference. If we take a listen, we can hear that both tracks are currently playing back at the session tempo, matching up with the click.
(drum music) You can also see that each track contains two clips that are each two bars long. But that length is relative to the session tempo of 102 beats per minute. If we change the session tempo, that will affect the duration of each bar in absolute time. To demonstrate, I'll disable the tempo ruler with this button here.
And now I'm in manual tempo mode, using a tempo of 120 beats per minute. And we can see that something has changed with my tracks. Let's start by listening to the Midi drums in isolation. So I'll solo that. (drum music) So we can hear that the click is now playing at the new faster tempo of 120 beats per minute, and the Midi drums have sped up to match. But if we listen to the audio drums, we'll hear something different.
(drum music) Here the audio clips have retained their original position and tempo, and they're now out of time with the click. So Midi clips are flexible. They stretch and contract like a rubber band, speeding up and slowing down to match the session tempo. But audio clips are like solid blocks of concrete. Their size is fixed and unchanging, regardless of the session tempo. This behavior is based, in part, on the track time base, with audio tracks being sample based by default, and instrument tracks being tick based.
As a result, the audio material is aligned to sample locations in the session, based on the sample rate. At a sample rate of 44.1 kilohertz, there are 44,100 sample locations in every second, and those locations don't move with tempo changes. By contrast, Midi material is aligned to tick based locations. A tick is a subdivision of the beat, with 960 ticks comprising a quarter note. So these locations are tied to the session tempo, with the bars, beats, and ticks occurring earlier at a higher tempo, and later at a lower tempo.
If I modify the session tempo by dragging this value up and down, you can see the effect that it has on the bar's beats ruler, and on the Midi clips. And we can hear the effect as well. (drum music) So that's the basic difference between tick based timing and sample based timing.
Clips on tick based tracks align to the session tempo, while clips on sample based tracks align to sample locations. Because Midi information is essentially just instructions about what notes to play, when to play them, and how long to hold them, the instructions can easily be sped up or slowed down, so tracks that use Midi data are tick based by default. Audio information, on the other hand, is stored as a series of samples, with each sample having a defined location within the clip.
Thus, audio tracks use sample based timing by default.
- Starting a new session
- Customizing settings
- Optimizing the performance of Pro Tools
- Importing loops and tracks
- Working with meter changes
- Recording multiple takes
- Changing the track timebase
- Editing MIDI clips
- Warping sound and tightening rhythm with Elastic Audio
- Using the Smart Tool
- Color coding tracks
- Editing on the grid
- Working with AudioSuite plug-ins
- Working with sends, plug-ins, and master faders
- Working with track subsets
- Finalizing and exporting media