small problem with math function

[jhamill]

So I had to make a program that calculates the volume of sound at a different distance, given a reference difference, and sound level, and the new distance. It works sometimes but depends on what values I put in.
Much of the time it tells me the new volume level is the same as the initial (whatever i set it as) but then other times it works. It must be a problem with the actual mathematical equation but I cant seem to spot an error.

package lab8;

import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;

@SuppressWarnings("serial")
public class GUISoundLevels extends JFrame implements ActionListener {
	private JLabel inputSoundLevelLabel;
	private JTextField inputSoundLevelText;
	private JLabel distance1Label;
	private JTextField distance1Text;
	private JLabel distance2Label;
	private JTextField distance2Text;
	private JButton go;
	private JTextField outputSoundLevel;
	
	
	public GUISoundLevels() {
		super("Sound Levels: GUI");
		setSize(575,300);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		Container myPane = getContentPane();
		myPane.setLayout(new FlowLayout());
		inputSoundLevelLabel = new JLabel("Enter reference sound level (in decibels)");
		inputSoundLevelText = new JTextField(20);
		distance1Label = new JLabel("Enter the reference distance (in meters)");
		distance1Text = new JTextField(20);
		distance2Label = new JLabel("Enter the new distance (in meters)");
		distance2Text = new JTextField(20);
		go = new JButton("go");
		outputSoundLevel = new JTextField("output will appear here", 30);
		add(inputSoundLevelLabel);
		add(inputSoundLevelText);
		add(distance1Label);
		add(distance1Text);
		add(distance2Label);
		add(distance2Text);
		add(go);
		go.addActionListener(this);
		add(outputSoundLevel);
		setVisible(true);
	}
	
	public void actionPerformed(ActionEvent arg0) {
	
	int inSoundLevel = new Integer(inputSoundLevelText.getText());
	int refDistance = new Integer(distance1Text.getText());	
	int newDistance = new Integer(distance2Text.getText());		
	int finalSoundLevel = new Integer((int) ((inSoundLevel -Math.round( 20 * Math.log10(newDistance/refDistance) ) )));
	outputSoundLevel.setText("The SPL of the sound at distance " + Integer.toString(newDistance) + " is " + Integer.toString(finalSoundLevel) + " dB");
	}		
	
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		new GUISoundLevels();
	}

}