changing pitch when accelerating

Unity Engine
1

I’m trying to add audio to a tank. I’m working on a engine sound effect that will increase in pitch whenever the player accelerates. Then when they deccelerate, the pitch will gradually decrease once the player stops holding down the button to go forward. In my case, when they go forward (w), I want the pitch to increases from .5 to 1 in about 3 seconds. Then decrease back to 0.5 in 3 seconds as well.

With this code, when I press the w key, the pitch immediatly goes from 0.5 to 1 without any gradual change.

function Update {

if(Input.GetKeyDown("w")){
	
      audio.pitch = Mathf.Lerp(0.5,1,Time.time);

         }

}

as a side note, I have a audio source attached to the object with this script using the engine sound effect. Although, how would I reference the engine sound if I have more than one audio source component?

2

I would also know how this is possible . Like I have a small game that would be prefect for pitch control .

3

can anyone help? I have an idea of how lerps work through tutorials but i’m anxious to start using them in practical senarios for my projects.

4

Take a look at the Unity car tutorial. They have a soundcontroller on the car that does a lot of pitch changing.

5

For the lerp function, you need to know that the time part works between 0 and 1 so you can use fraction if you want a precise timed lerp:

audio.pitch = Mathf.Lerp(0.5,1,(Time.time-(Time.time-startTime)/duration); → you can set the duration and when the fraction become equal to 1 the lerp is at max.

if you want to link the lerp with the speed you can calculate the current percentage of you speed 25% → speedPerc = 0.25f

audio.pitch = Mathf.Lerp(0.5,1,speedPerc); but in that case you can strait link up the current pitch like that audio.pitch = PitchMax * speedPerc; and you can set up the pitchmax, you can also work with an range… Plenty of ways to do it really…
I never use the pitch for cars, but i’m using lerps a lot so i hope it’s helpfull :wink:

6

I’m a bit confused with your example of

audio.pitch = Mathf.Lerp(0.5,1,(Time.time-(Time.time-startTime)/duration); .

is startTime a command or something? I cant find it in the scripting reference. Also why are there - signs, and how come Time.time is enclosed in brackets, and why is Time.time-startTime in
brackets??.

as for this example

audio.pitch = Mathf.Lerp(0.5,1,speedPerc);

I’m not sure what your showing because all I see different is a variable called speedPerc

I’m very noob at scripting. Could you provide a working code for these examples so I can check to see if it works?

7

I am not comfortable wth lerps and slerps but since pitch is just a float that you can set!!!..

Why not just add or subtract the value over time?

Meaning in update…
Audio.pitch = pitch + 1;

This is very rough obviously but you can just add or subtract at will!!

8

You’ll obviously need modify this to get currentSpeed and maxSpeed from somewhere, probably your rigidbody’s velocity.

var minPitch : float = 1.0;
var maxPitch : float = 2.0;

private var pitchModifier : float;

function Update(){
    pitchModifier = maxPitch - minPitch;
    audio.pitch = minPitch + (currentSpeed/maxSpeed)*pitchModifier;
}
9

Legend, I tried your script but it actually did the same thing as mine. I filled in the values for maxSpeed and currentSpeed but when I press w it immediatly jumps to a value with no gradual change.

I made this script that half way works. When I hold down W it starts to gradually increase the pitch. Although, I have not figured out yet how to set pitch limits so the pitch can go up infinitly.

I want the pitch to decrease gradually when the w key is not being pressed, how can I do this? Right now it just immediatly drops.

function Update () {

	if(Input.GetKey("w")){
	
		
    audio.pitch += 1* Time.deltaTime;
	
	}
	
	if(Input.GetKeyUp("w")){
	
		
    audio.pitch -= 0.7;
	}

}
10

Does your object gradually accelerate to top speed? how did you fill those values in? I imagine it being something like this:

var minPitch : float = 1.0;
var maxPitch : float = 2.0;
var maxSpeed : float = 20.0; //tweak to your vehicle

private var pitchModifier : float;

function Update(){
    var currentSpeed = rigidbody.velocity.magnitude;
    pitchModifier = maxPitch - minPitch;
    audio.pitch = minPitch + (currentSpeed/maxSpeed)*pitchModifier;
}

The pitch should increase/decrease from minPitch to maxPitch as gradually as your vehicle accelerates.

11

Hey , I wanted all game audio to pitch up and down , would I apply a script to the main camera ?

12

No, you’d have to find all audio sources in the scene and modify their pitches.

13

The code works. Although i’m having a struggle to understand it. Could you explain?

One thing I noticed is when the tank falls off a cliff or is free falling, the engine revs up and goes to maximum pitch. How can I change it so the pitch will only respond to the engine and not respond to velocity like falling or sliding?

14

Perhaps even better and more accurate would be to make the pitch a factor of distance which you can measure in Update().

15

A factor of distance?? How would I do that.

16 
var distance : float = Vector3.Distance(sound.transform.position, viewer.transform.position);
17

I’m not sure what your referring to. It appears to be like code to handle 3D sound or something, but right now im trying to work on the tanks pitch for the engine to make it increase the faster the tank goes, and decrease when it starts to slow down. So far legends script works but when the tank falls or slides, the engine pitch increases.

18

Oh, I am sorry, I was assuming you wanted a doppler effect.

In that case I would make the power/torque, what have you of the engine a factor of the pitch.

So if you are moving at 10 clips… or if you can be stationary and rev your engine, whatever that var is, use it as a factor in the pitch.

19

Heres my code for the tank body. So far i’m using AddRelativeForce to move the tank forward. Do I make AddRelativeForce related somehow to the pitch?

private var movement : float = 0;
private var rotation : float = 0;
var speed = 2;
var rotateSpeed = 2;
var rotateSlowDown : float = 0;

var minPitch : float = 1.0;
var maxPitch : float = 2.0;
var maxSpeed : float = 20.0; //tweak to your vehicle
 
private var pitchModifier : float;



function FixedUpdate(){


var fwd = transform.TransformDirection(Vector3.up);

if(Physics.Raycast (transform.position, -fwd, 0.8)) {
       movement = Input.GetAxis("Vertical");
        rotation = Input.GetAxis("Horizontal")*rotateSpeed;
		
		
    }
	 else
	 {
	 print("did we fall off something?");
	}
	rotation *= Time.deltaTime;
    rigidbody.AddRelativeForce(Vector3(0,0,movement*speed));
	
	
 transform.Rotate (0, rotation, 0); 
    Debug.DrawRay(transform.position,-fwd * 0.8,Color.red);
	
	if(rotation&movement)
	{
	
		rigidbody.AddRelativeForce(Vector3(0,0, -rotateSlowDown));
	
	}
	
	
	

var currentSpeed = rigidbody.velocity.magnitude;
    pitchModifier = maxPitch - minPitch;
    audio.pitch = minPitch + (currentSpeed/maxSpeed)*pitchModifier; 



}

For easier reading, here is the code in the script regarding audio and pitch.

var minPitch : float = 1.0;
var maxPitch : float = 2.0;
var maxSpeed : float = 20.0; //tweak to your vehicle

function FixedUpdate(){

private var pitchModifier : float;

var currentSpeed = rigidbody.velocity.magnitude;
    pitchModifier = maxPitch - minPitch;
    audio.pitch = minPitch + (currentSpeed/maxSpeed)*pitchModifier; 
}
20

well it looks like you have one gear? Fast and stopped?

edit.
Basically what you need to do is if when idle, pitch equals 1, then what driving pitch = 2 and everything in between.