No. And yes. No, the audio does not go to the track. Yes, the audio goes to the XF tone generator, you use the Midi data on the track to control when, how loud, and for how long each audio clip plays.... Midi data 'instructs' the playback of audio.

The Track of the Motif XF sequencer contain only MIDI data, not audio. This difference is not just semantics, but important to fully understand. The only data that gets written to the tracks of the XF sequencer are Midi events that trigger audio playback. That audio is placed into what Yamaha calls a Waveform . This organizes audio in such a way it can be recalled and played back in response to MIDI events.

This audio is placed in the XF by Yamaha at the factory, or by you. The factory gives you 3,977 Waveforms, you can load 128 to internal RAM and 2,048 to each Flash Board. You can place any Waveform in a Motif XF entity called a VOICE. This can be selected in a multi-timbral set up so that a Midi event can cause the audio Waveform to playback.

This is true of the Full Concert Grand piano and true if ant custom audio you sample, or load into the XF. Say you load a .Wav file
The first thing it does is add some musical parameters to it. It assigns it a key from which it will sound at normal pitch, and it assigns it a basic velocity range that will trigger playback, it is assigned an envelope that turns it on immediately, holds it at full volume as long as the is held, and disappears immediately on key release. And it plays it in the forward direction. And either loops or plays once. It builds these parameters onto your .wav data and it is now a Motif XF Waveform. These additional parameters are what make a Motif Waveform different from a .WAV (any media player can playback the wave as a .wav, but the Waveform has the ability to playback through 128 separate audio channels simultaneously, play at original pitch when triggered with its home key but play at different pitches and speed for each note up and down the keyboard, when triggered with multiple simultaneous key presses. It can playback softly when the key is struck lightly and playback louder when the key is struck firmly, etc., etc., these additional parameters make the musically useful.

That's what happening.

A waveform is regular audio data plus a set of Motif XF parameters that give it musical context. The fact that the audio is a "sample", means it's been trimmed so playback begins as soon as a key is pressed. The audio being linear will continue as long as the key is held. And being efficient,when the duration of the note-on event is reached, audio stops. That is how the Sampler is Intgrated into the Motif XF Sequencer. The audio is contained in a special User Sample Voice.

The Integrated Sampling Sequencer lets MIDI event control the playback of audio. The audio is contained in the synthesizer tone generator. Only MIDI data is recorded to the tracks.

Hope that helps.

Thank you!!