This is a code to move servos by music

spectrum7Servo.pde

/**
 * I forgot this is original code or modified one.
 * If you use this code, take care about the license.
 * Sorry for inconvinence.
 *
 * This code is for SparkFun Spectrum Shield
 * https://www.sparkfun.com/products/13116
 *
 * Sample movie
 * https://www.youtube.com/watch?v=MphrcR2r3j4
 */

#include <Servo.h>

const int SERVONUM        = 7;
const int servopin[]      = {6,7,8,9,10,11,12};
const int spectrumStrobe  = 4;
const int spectrumReset   = 5;
const int spectrumAnalog  = 0;  //0: left channel, 1: right channel
const int dispBand        = 0;
// Spectrum analyzer read values will be kept here.
int Spectrum[SERVONUM];
Servo servoAry[SERVONUM];

void setup() {
  Serial.begin(9600);
  //Setup pins to drive the spectrum analyzer. It needs RESET and STROBE pins.
  pinMode(spectrumReset, OUTPUT);
  pinMode(spectrumStrobe, OUTPUT);
  for ( int i = 0; i<SERVONUM; i++ ) {
    pinMode( servopin[i], OUTPUT );
  }
  
  initSpectrum();
  
  for ( int i = 0; i<SERVONUM; i++ ) {
    servoAry[i].attach(servopin[i]);
  }
}

void loop() {
  readSpectrum();
  
  printBlockToSerial( Spectrum[dispBand]);
  //analogWrite( ledPin, Spectrum[freq] );

  for ( int i=0; i<SERVONUM; i++ ) {
    servoAry[i].write(map(Spectrum[i],400,900,0,30));
  }
  delay(15);
}

void initSpectrum()
{
//Init spectrum analyzer
  digitalWrite(spectrumStrobe,LOW);
    delay(1);
  digitalWrite(spectrumReset,HIGH);
    delay(1);
  digitalWrite(spectrumStrobe,HIGH);
    delay(1);
  digitalWrite(spectrumStrobe,LOW);
    delay(1);
  digitalWrite(spectrumReset,LOW);
    delay(5);
}


// Read 7 band equalizer.
void readSpectrum()
{
  byte Band;
  for(Band=0;Band <7; Band++)
  {
    //Spectrum[Band] = (analogRead(spectrumAnalog) + analogRead(spectrumAnalog) ) >>1; //Read twice and take the average by dividing by 2
    Spectrum[Band] = analogRead(spectrumAnalog>>2);	//    Spectrum[Band] is a global array to hold the readings
    digitalWrite(spectrumStrobe,HIGH);
    digitalWrite(spectrumStrobe,LOW);
  }
}

void printBlockToSerial( int spectrum )
{
  int i;
  for (i=0; i<spectrum/10; i++)
  {
    Serial.print( "X" );
  }
  Serial.println( "" );
}