Weird Problem with the Arduino - it seems that there is a problem using pin 11 and 13 together but if I use a different pwm pin like pin 5. It's okay.

AWeirdProblemArduino.ino

#include "SimplestLibrary.h"
Sweeper sweeper; 
Buzzer buzzer;
AnalogLED led;

int f1 = 3000;
int f2 = 4500;
int f = 0;

void setup() {
  sweeper.New(f1, f2, BACKANDFORTH); 
  buzzer.New(13);
  led.New(11);
}

void loop() {
  f = sweeper.Update(1); 
  buzzer.Play(f, 4, 2);
  led.NewBrightness(map(f, f1, f2, 0, 50));
  delay(1);
}

SimplestLibrary.cpp

#include "SimplestLibrary.h"

/**********************************
 * ANALOG LED 
 **********************************/

void AnalogLED::New(int p){
  _pin = p;
  pinMode(_pin, OUTPUT);
}

void AnalogLED::NewBrightness(int b){
  analogWrite(_pin, b);
}

/**********************************
 * SWEEPER
 **********************************/

void Sweeper::New(int s, int e, byte x){
  
  if(s < e ){
   _dir = FORWARD;
   _start = s;
   _end = e;
  }else{
    _dir = REVERSE;
    _start = e;
    _end = s; 
  }
  _sweepsMade = 0;
  _type = x;
  _state = s;
}

int Sweeper::Update(bool itsTime){

  if(itsTime){
  
    if(_type == NORMAL){
      _dir == FORWARD ? _forward() : _reverse(); 
    }else{
      _backAndForth();
    }

  }

  return _state;
}

unsigned long Sweeper::SweepsMade(){
  return _type == NORMAL ? _sweepsMade : _sweepsMade / 2;
}

void Sweeper::_forward(){
  _state++;
  if(_state > _end){
    _state = _start;
    _sweepsMade++;
  }
}

void Sweeper::_reverse(){
  _state--;
  if(_state < _start){
    _state = _end;
    _sweepsMade++;
  }
}

void Sweeper::_backAndForth(){
  if (_dir == FORWARD){
    
    if(_state < _end){
      _state++;

    }else{
      _dir = REVERSE;
      _state--;
      _sweepsMade++;
    }

  }else{ //reverse
    
    if(_state > _start){
      _state--;
    }else{
      _dir = FORWARD;
      _state++;
      _sweepsMade++;
    }
  }
}

/**********************************
 * BUZZER
 **********************************/
void Buzzer::New(int p){
    _pin = p;
    pinMode(_pin, OUTPUT);
}

void Buzzer::Play(int pitch, float period, int d){
  tone(_pin, pitch, period);
  delay(d);
}

SimplestLibrary.h

#include <Arduino.h>

/********************************** CONSTANTS **********************************/

const bool BACKANDFORTH = 0;
const bool NORMAL = 1;
const bool FORWARD = 0;
const bool REVERSE = 1;

/********************************** CLASSES **********************************/

class AnalogLED{
  int _pin;
  int _brightness;
  public:
  void New(int p);
  void NewBrightness(int b);
};

class Sweeper{
  bool _dir;
  bool _type; 
  int _state;
  int _start;
  int _end;
  unsigned long _sweepsMade;
  public:
  void New(int s, int e, byte x);
  int Update(bool itsTime);
  unsigned long SweepsMade();
  private:
  void _forward();
  void _reverse();
  void _backAndForth();
};

class Buzzer{
  int _pin;
  public:
  void New(int p);
  void Play(int freq, float period, int d);
};