Drastic Lag While Reading Potentiometer Value. (EHX RTG Clone)

Projects General Guidance
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So long story short; via combing through the internet and patchworking codes from here and there, I managed to make myself an arduino based Ehx Rtg Clone. Its basically a random tone generator with adjustable rate. The only problem I have is that when I turn the rate knob (a 10k pot in this case) slowly, it works. If I turn it fast however it lags incredibly. Especially while increasing the rate. The code is down below for you to check out and maybe come up with an answer of just to try out and have fun!

int sensorPin = 0; 
int ledPin = 11;
int sensorValue = 0; 
int newVal = 0;
int speakerPin = 9;
int length = 25; 
char notes[] = "cdefgabCDEABZYXFGHJKLMNOPR";
int beats[] = {1, 1, 1, 1, 1, 1, 1, 1};
long randomNo;
void playTone(int tone, int duration ) {
  
  for (long i = 0; i < duration * 1000L; i += tone * 2) {
    digitalWrite(speakerPin, HIGH);
    delayMicroseconds(tone);
    digitalWrite(speakerPin, LOW);
    delayMicroseconds(tone);
  }
}

void playNote(char note, int duration) {
 
char names[] = { 'c', 'd', 'e', 'f', 'g', 'a', 'b', 'C','D','E', 'A', 'B', 'Z', 'Y', 'X', 'F', 'G', 'H', 'J', 'L', 'M', 'N','O','P', 'R', };
int tones[] = { 261*2, 293*2, 329*2, 349*2, 392*2, 440*2, 493*2, 523*2, 587*2, 659*2, 698*2, 783*2, 880*2, 987*2, 1046*2, 1174*2, 1318*2, 1396*2, 1567*2, 1760*2, 1975*2, 2093*2, 2349*2, 2637*2, 2793*2 };

  for (int i = 0; i < 25; i++) {
  if (names[i] == note) {
    playTone(tones[i], duration);
    }
  }
}

void setup() {
pinMode(ledPin, OUTPUT);
pinMode(speakerPin, OUTPUT);
 pinMode(13, OUTPUT); 
 pinMode(12, OUTPUT); 
Serial.begin(9600);
}

void loop() {
int sensorValue = analogRead(sensorPin);// read the value from the sensor:

newVal = map(sensorValue, 0, 1023, 0, 255); //adjust the value 0 to 900 to
analogWrite(11 , newVal );

Serial.println(sensorValue);

for (int i = 0; i < length; i++) {
randomNo = random (0,24);
      Serial.println(randomNo);
      int l = randomNo;
      if(l==0){playNote(notes[0], beats[0] * newVal+1);}
      if(l==1){playNote(notes[1], beats[0] * newVal+1);}
      if(l==2){playNote(notes[2], beats[0]* newVal+1);}
      if(l==3){playNote(notes[3], beats[0] * newVal+1);}
      if(l==4){playNote(notes[4], beats[0]* newVal+1);}
      if(l==5){playNote(notes[5], beats[0] * newVal+1);}
      if(l==6){playNote(notes[6], beats[0]* newVal+1);}
      if(l==7){playNote(notes[7], beats[0]* newVal+1);}
      if(l==8){playNote(notes[8], beats[0]* newVal+1);}
      if(l==9){playNote(notes[9], beats[0]* newVal+1);}
      if(l==10){playNote(notes[0], beats[0] * newVal+1);}
      if(l==11){playNote(notes[1], beats[0] * newVal+1);}
      if(l==12){playNote(notes[2], beats[0]* newVal+1);}
      if(l==13){playNote(notes[3], beats[0] * newVal+1);}
      if(l==14){playNote(notes[4], beats[0]* newVal+1);}
      if(l==15){playNote(notes[5], beats[0] * newVal+1);}
      if(l==16){playNote(notes[6], beats[0]* newVal+1);}
      if(l==17){playNote(notes[7], beats[0]* newVal+1);}
      if(l==18){playNote(notes[8], beats[0]* newVal+1);}
      if(l==19){playNote(notes[9], beats[0]* newVal+1);}
      if(l==20){playNote(notes[0], beats[0] * newVal+1);}
      if(l==21){playNote(notes[1], beats[0] * newVal+1);}
      if(l==22){playNote(notes[2], beats[0]* newVal+1);}
      if(l==23){playNote(notes[3], beats[0] * newVal+1);}
      if(l==24){playNote(notes[4], beats[0]* newVal+1);}
     
}
}

EDIT: I have added

delay(10);{
}

to the end of the loop and seemed to reduce the lag a bit.