Pause in minim

My song only pauses for half a second. How do I fix it?

import ddf.minim.spi.*;
import ddf.minim.signals.*;
import ddf.minim.*;
import ddf.minim.analysis.*;
import ddf.minim.ugens.*;
import ddf.minim.effects.*;


Minim minim;
AudioPlayer song;
float lvl;
int BG, change;
PImage play, pause, on, off, bg;
boolean power;

void setup()
{
  size(800, 800);
  minim = new Minim(this);
  song = minim.loadFile("Song.mp3");
  song.play();
  change = 100;
  BG = 0;
  power = false;
  play = loadImage("play.png");
  pause = loadImage("pause.png");
  on = loadImage("on.jpg");
  on.resize(100, 100);
  off = loadImage("off.jpg");
  bg = loadImage("download.jpg");
  frameRate(50);
}

void draw() {
  background(BG);
  if (!power) {
    BG=0;
    change = 100;
    image(off, 25, 25);
    song.pause();
    song.rewind();
  } else {
    beat();
    song.play();
    BG = 255;
    image(on, 5, 5);
    beat();
  }
}

void beat() {
  lvl = song.mix.level();
  image(pause, width/2-50, 50);

  if (lvl > 0.1) {
    change = change + 10;
  } else {
    change = change - 5;
  }
  change = constrain(change, 100, 200);
  fill(#F00707);
  ellipse(width/2, height/2, change, change);
}

void mouseClicked() {
  if (mouseX<75 && mouseY<75) {
    power = !power;
  }
}
void keyReleased() {
  //pauses song when spacebar is pressed
  if (key == ' ') {
    if (song.isPlaying()) song.pause();
    else song.play();
  }
}