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diff --git a/src/main/java/com/jsyn/unitgen/MultiTapDelay.java b/src/main/java/com/jsyn/unitgen/MultiTapDelay.java
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+++ b/src/main/java/com/jsyn/unitgen/MultiTapDelay.java
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+/*
+ * Copyright 2023 Phil Burk
+ *
+ * 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.unitgen;
+
+import com.jsyn.dsp.SimpleDelay;
+import com.jsyn.ports.UnitInputPort;
+
+/**
+ * Delay with multiple read positions and associated gains.
+ */
+public class MultiTapDelay extends UnitFilter {
+
+    /** Pre-delay time in milliseconds. */
+    public UnitInputPort preDelayMillis;
+    private final int mMaxPreDelayFrames;
+    private SimpleDelay mPreDelay;
+    private SimpleDelay mDelay;
+    private final int[] mPositions;
+    private final float[] mGains;
+
+    private int mPreDelayFrames = 0;
+
+    /**
+     * Construct a delay line with specified taps.
+     * The allocated size of the delay line will be the maximum position plus the maxPreDelayFrames.
+     * @param positions delay index, eg. 172 for Z(n-172)
+     * @param gains multiplier for the corresponding position
+     * @param maxPreDelayFrames extra allocated frames for pre-delay before the taps
+     */
+    public MultiTapDelay(final int[] positions,
+                final float[] gains,
+                final int maxPreDelayFrames) {
+        mPositions = positions;
+        mGains = gains;
+
+        preDelayMillis = new UnitInputPort("PreDelayMillis");
+        double maxMillis = maxPreDelayFrames * 1000.0 / 44100; // TODO handle unknown frame rate better
+        preDelayMillis.setup(0.0, Math.min(10.0, maxMillis), maxMillis);
+        addPort(preDelayMillis);
+        mMaxPreDelayFrames = Math.max(1, maxPreDelayFrames);
+        mPreDelay = new SimpleDelay(maxPreDelayFrames);
+
+        int maxPosition = 0;
+        for (int position : positions) {
+            maxPosition = Math.max(maxPosition, position);
+        }
+        mDelay = new SimpleDelay(maxPosition);
+    }
+
+    @Override
+    public void generate(int start, int limit) {
+        double[] inputs = input.getValues();
+        double[] outputs = output.getValues();
+
+        double preDelayMS = preDelayMillis.getValues()[0];
+        int preDelayFrames = (int)(preDelayMS * 0.001 * getFrameRate());
+        preDelayFrames = Math.max(1, Math.min(mMaxPreDelayFrames, preDelayFrames));
+
+        for (int i = start; i < limit; i++) {
+            mPreDelay.write((float) inputs[i]);
+            mDelay.write(mPreDelay.read(preDelayFrames));
+            mPreDelay.advance();
+            double sum = 0.0;
+            for (int tap = 0; tap < mPositions.length; tap++) {
+                sum += mDelay.read(mPositions[tap]) * mGains[tap];
+            }
+            mDelay.advance();
+            outputs[i] = sum; // mix taps
+        }
+    }
+}