I have been tinkering with the beat detection of minim but I can't get it to work with the line in, anyone got an idea how to make this code work?

1. import ddf.minim.*;
   import ddf.minim.effects.*;
   import ddf.minim.analysis.*;
   
   Minim minim;
   AudioInput in;
   BandPass bpf;
   BeatDetect beat;
   BeatListener bl;
   
   void setup()
   {
     minim = new Minim(this);
     in = minim.getLineIn();
     bpf = new BandPass(55, 12, in.sampleRate());
     in.addEffect(bpf);
     beat = new BeatDetect(in.bufferSize(), in.sampleRate());
     beat.setSensitivity(300);
     bl = new BeatListener(beat, in);
     //beat.detect(in.mix);
     //bpf filter helps beatDetection algo when bass beat detection is only //wanted
   }
   void draw(){
   
     if ( beat.isOnset() )
     {
       println("beat!");
     //what you want it to do
     }
   }
   
   void stop()
   {
     // always close Minim audio classes when you are finished with them
     in.close();
     // always stop Minim before exiting
     minim.stop();
     // this closes the sketch
     super.stop();
   }
   class BeatListener implements AudioListener
   {
     private BeatDetect beat;
     private AudioInput source;
    
     BeatListener(BeatDetect beat, AudioInput source)
     {
       this.source = source;
       this.source.addListener(this);
       this.beat = beat;
     }
    
     void samples(float[] samps)
     {
       beat.detect(source.mix);
     }
    
     void samples(float[] sampsL, float[] sampsR)
     {
       beat.detect(source.mix);
     }
   }