Multi piezo

#include <Timer.h>
#include <MIDI.h>
MIDI_CREATE_DEFAULT_INSTANCE();
Timer t[10];
float notes[] = {
  8.1757989156,  8.6619572180,  9.1770239974,  10.3008611535,  10.3008611535,  10.9133822323,  11.5623257097,  12.2498573744,  12.9782717994,  13.7500000000,  14.5676175474,  15.4338531643,  16.3515978313,  17.3239144361,  18.3540479948,  19.4454364826,  20.6017223071,  21.8267644646,  23.1246514195,  24.4997147489,  25.9565435987,  27.5000000000,  29.1352350949,  30.8677063285,  32.7031956626,  34.6478288721,  36.7080959897,  38.8908729653,  41.2034446141,  43.6535289291,  46.2493028390,  48.9994294977,  51.9130871975,  55.0000000000,  58.2704701898,  61.7354126570,  65.4063913251,  69.2956577442,  73.4161919794,  77.7817459305,  82.4068892282,  87.3070578583,  92.4986056779,  97.9988589954,  103.8261743950,  110.0000000000,  116.5409403795,  123.4708253140,  130.8127826503,  138.5913154884,  146.8323839587,  155.5634918610,  164.8137784564,  174.6141157165,  184.9972113558,  195.9977179909,  207.6523487900,  220.0000000000,  233.0818807590,  246.9416506281,  261.6255653006,  277.1826309769,  293.6647679174,  311.1269837221,  329.6275569129,  349.2282314330,  369.9944227116,  391.9954359817,  415.3046975799,  440.0000000000,  466.1637615181,  493.8833012561,  523.2511306012,  554.3652619537,  587.3295358348,  622.2539674442,  659.2551138257,  698.4564628660,  739.9888454233,  783.9908719635,  830.6093951599,  880.0000000000,  932.3275230362,  987.7666025122,  1046.5022612024,  1108.7305239075,  1174.6590716696,  1244.5079348883,  1318.5102276515,  1396.9129257320,  1479.9776908465,  1567.9817439270,  1661.2187903198,  1760.0000000000,  1864.6550460724,  1975.5332050245,  2093.0045224048,  2217.4610478150,  2349.3181433393,  2489.0158697766,  2637.0204553030,  2793.8258514640,  2959.9553816931,  3135.9634878540,  3322.4375806396,  3520.0000000000,  3729.3100921447,  3951.0664100490,  4186.0090448096,  4434.9220956300,  4698.6362866785,  4978.0317395533,  5274.0409106059,  5587.6517029281,  5919.9107633862,  5919.9107633862,  6644.8751612791,  7040.0000000000,  7458.6201842894,  7902.1328200980,  8372.0180896192,  8869.8441912599,  9397.2725733570,  9956.0634791066,  10548.0818212118,  11175.3034058561,  11839.8215267723,  12543.8539514160
};
long pins[] = {
  2, 3, 4, 5, 6, 7, 8, 9, 10, 11
};


void setup() {
    MIDI.setHandleNoteOn(handleNoteOn);  // Put only the name of the function

    // Do the same for NoteOffs
    MIDI.setHandleNoteOff(handleNoteOff);

    // Initiate MIDI communications, listen to all channels
    MIDI.begin(MIDI_CHANNEL_OMNI);
    Serial.begin(9600);
    pinMode(13, OUTPUT); //LED
    for(int i = 0; i<11; i++) {
      pinMode(pins[i], OUTPUT);
    }
}

void handleNoteOn(byte channel, byte pitch, byte velocity) {
  int chan = map(channel, 1, 16, 1, 10);
  if(velocity > 0) {
  switch (chan) {
    case 1:
      playNote(pins[0], notes[pitch]);
      break;
    case 2:
      playNote(pins[1], notes[pitch]);
      break;
    case 3:
      playNote(pins[2], notes[pitch]);
      break;
    case 4:
      playNote(pins[3], notes[pitch]);
      break;
    case 5:
      playNote(pins[4], notes[pitch]);
      break;
    case 6:
      playNote(pins[5], notes[pitch]);
      break;
    case 7:
      playNote(pins[6], notes[pitch]);
      break;
    case 8:
      playNote(pins[7], notes[pitch]);
      break;
    case 9:
      playNote(pins[8], notes[pitch]);
      break;
    case 10:
      playNote(pins[9], notes[pitch]);
      break;
  }
  }
}
void handleNoteOff(byte channel, byte pitch, byte velocity) {
  int chan = map(channel, 1, 16, 1, 10);
  switch (chan) {
    case 1:
      stopNote(pins[0]);
      break;
    case 2:
      stopNote(pins[1]);
      break;
    case 3:
      stopNote(pins[2]);
      break;
    case 4:
      stopNote(pins[3]);
      break;
    case 5:
      stopNote(pins[4]);
      break;
    case 6:
      stopNote(pins[5]);
      break;
    case 7:
      stopNote(pins[6]);
      break;
    case 8:
      stopNote(pins[7]);
      break;
    case 9:
      stopNote(pins[8]);
      break;
    case 10:
      stopNote(pins[9]);
      break;
  }
}

void loop() {
  MIDI.read();
  t[1].update();
  t[2].update();
  t[3].update();
  t[4].update();
  t[5].update();
  t[6].update();
  t[7].update();
  t[8].update();
  t[9].update();
  t[10].update();
}
long ids[10];
void playNote(int pin, unsigned long freq) {
  float ms = 1000/freq/2;
  ids[pin] = t[pin].oscillate(pin, ms, HIGH);
}

void stopNote(int pin) {
  t[pin].stop(ids[pin]);
}