Primer on event sheets (especially parameter sheet) please

I’m new to FMOD and I’m struggling to understand the different sheets within an Event and how they work together.

I have seen the forum posts explaining that New Event > New 2D/3D Timeline creates an event with a Timeline Sheet only and that New Event > New 2D/3D Action creates an event with an Action Sheet only… and that these are just templates and we have total control about which sheets we add and remove. Cool. Got it.

I think I understand Timeline Sheet and Action Sheet just a little bit but I could still do with more explanation. In my limited understanding

  • Action Sheet is the most basic and is well suited to one-shot SFX where you Play() and expect it to go from start to finish and then stop on its own; e.g. gunshots or explosions.
  • Timeline Sheet is more feature-rich and lets you have loop regions, segments, transitions etc… It’s also got tempo control which I still need to get my head around as I think of audio in terms of samples, sample rate and time vs MIDI notes in terms of notes, beats and tempo.

But the one that’s got me most confused is the Parameter Sheet. Please could someone explain the Ride-on Mower example from the Kart tutorial. In particular:

  1. It looks like this has 2 parameter sheets: RPM and Load, but no Timeline Sheet and no Action Sheet. Is that right? And if so, how come we don’t need either of them? (The fact that there’s no New Event > New Parameter Sheet suggests this is not a valid thing to do.)

  2. On the RPM sheet, I understand how the samples have been placed on the parameter axis to come in an out and mix between samples for different values of RPM. I can also see that each particular sample is looped infinitely, which makes sense. The questions I have around this are:
    a) What does ‘Cut’ mean? What would be different if it wasn’t enabled? It’s on the sound controls to the left of the loop control.
    b) If I resize a sound in one of the tracks so that it covers a wider range of RPM values, I would expect that it gets played when the RPM parameter is in that wider range of values. However when I tried this, visually the sample appears to be stretched/squashed. Is that just a visual thing or is it affecting the playback rate of the sample?
    c) I see the volume curves on the automation track and how that is impacted by RPM. However if I change RPM I can hear a pitch change too. Where is that being controlled?

  3. On the Load sheet there are the automation tracks but no audio. How does that work? It looks like Load is using the audio on the RPM sheet, but how?

  4. If I am setting up a new event from scratch

    • How would I choose which parameter sheet gets the audio?
    • What would happen if I put audio on multiple sheets?

Sorry, lots of questions with subquestions. I’d love to get my head around this.

  1. That’s right, there’s no timeline sheet, and it’s a perfecly valid state, even though it’s not possible to create an event with a parameter sheet in one click.
    A parameter sheet, when the event is started, triggers the instruments which are on the current value of the parameter.

  2. a) “Cut”, if checked, means immediately after the playhead isn’t anymore overlapping the instrument (after a parameter value change), the playback is immediately cut. When unchecked, it finishes the current play before stopping. In the car exemple, it’s not that obvious because there are infinite audio loops, so the start and end of the audio files aren’t discernable.
    b) It’s as you said. The stretch only indicates the instrument is asyncronous (it’s necessarily the case in parameter sheets). It’s easier to understand on a timeline sheet: try to stretch sync and async instruments and to understand why it displays differently.
    c) I’m not in front of FMOD to verify but I remember there’s a pitch shifter effect automated on one or another track (maybe the master).

  3. All those sheets constitute a whole event. Load and RPM aren’t played independently but together. The load here only applies some modifications to the sound (but the raw sounds are triggered, as you saw, by the RPM sheet).

  4. The sounds should be on the parameter which dertermines which of those sounds should be played. But you can imagine 2 parameters, each with its set of sounds. For instance footsteps depending from boot type and from surface type, and you’d like to here at the same time the right boot sound and the right surface impact sound.

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Thank you for a phenomenal and question-by-question response. I’m starting to piece things together in my head and this has been really useful. :raised_hands:

I’ve worked out the pitch modulation. Each sound has an autopitch. From the documentation I can see that because these sounds are on the RPM sheet, it’s the RPM value that affects playback rate. I also see that for each sound, its “Root pitch” value (meaning the parameter value at which the sound plays back at 1x speed) is set based on where it is on the RPM scale.

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That’s right. I had never looked at this autopitch modulator before.