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diff --git a/src/com/jsyn/swing/ExponentialRangeModel.java b/src/com/jsyn/swing/ExponentialRangeModel.java
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+/*
+ * Copyright 2011 Phil Burk, Mobileer Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.jsyn.swing;
+
+/**
+ * Maps integer range info to a double value along an exponential scale.
+ * 
+ * <pre>
+ * 
+ *   x = ival / resolution
+ *   f(x) = a*(root&circ;cx) + b
+ *   f(0.0) = dmin
+ *   f(1.0) = dmax
+ *   b = dmin - a
+ *   a = (dmax - dmin) / (root&circ;c - 1)
+ *  
+ *   Inverse function:
+ *   x = log( (y-b)/a ) / log(root)
+ * 
+ * </pre>
+ * 
+ * @author Phil Burk, (C) 2011 Mobileer Inc
+ */
+public class ExponentialRangeModel extends DoubleBoundedRangeModel {
+    private static final long serialVersionUID = -142785624892302160L;
+    double a = 1.0;
+    double b = -1.0;
+    double span = 1.0;
+    double root = 10.0;
+
+    /** Use default root of 10.0 and span of 1.0. */
+    public ExponentialRangeModel(String name, int resolution, double dmin, double dmax, double dval) {
+        this(name, resolution, dmin, dmax, dval, 1.0);
+    }
+
+    /** Set span before setting double value so it is translated correctly. */
+    ExponentialRangeModel(String name, int resolution, double dmin, double dmax, double dval,
+            double span) {
+        super(name, resolution, dmin, dmax, dval);
+        setRoot(10.0);
+        setSpan(span);
+        /* Set again after coefficients setup. */
+        setDoubleValue(dval);
+    }
+
+    private void updateCoefficients() {
+        a = (getDoubleMaximum() - getDoubleMinimum()) / (Math.pow(root, span) - 1.0);
+        b = getDoubleMinimum() - a;
+    }
+
+    private void setRoot(double w) {
+        root = w;
+        updateCoefficients();
+    }
+
+    public double getRoot() {
+        return root;
+    }
+
+    public void setSpan(double c) {
+        this.span = c;
+        updateCoefficients();
+    }
+
+    public double getSpan() {
+        return span;
+    }
+
+    @Override
+    public double sliderToDouble(int sliderValue) {
+        updateCoefficients(); // TODO optimize when we call this
+        double x = (double) sliderValue / getMaximum();
+        double y = (a * Math.pow(root, span * x)) + b;
+        return y;
+    }
+
+    @Override
+    public int doubleToSlider(double dval) {
+        updateCoefficients(); // TODO optimize when we call this
+        double z = (dval - b) / a;
+        double x = Math.log(z) / (span * Math.log(root));
+        return (int) Math.round(x * getMaximum());
+    }
+
+    public void test(int sliderValue) {
+        double dval = sliderToDouble(sliderValue);
+        int ival = doubleToSlider(dval);
+        System.out.println(sliderValue + " => " + dval + " => " + ival);
+    }
+
+}