Derivatives sound like a highpass filter.

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+            input, audio {
+                display: block;
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+            <p>
+                Drop a file anywhere or <button id="choose">choose one from your filesystem.</button>
+            </p>
+            <select id="" disabled>
+                <option value="derivative-processor">derivative-processor</option>
+                <option value="integral-processor">integral-processor</option>
+                <option value="subtract-overlap" selected>subtract-overlap</option>
+            </select>
+            <audio controls></audio>
+
+
+            <ul>
+                <li>
+                    <code>derivative-processor</code>
+                    <p>Approximates the first derivative of the audio as a function respect to time.</p>
+                </li>
+                <li>
+                    <code>integral-processor</code>
+                    <p>Approximates the first integral of the audio as a function respect to time. Plus C of zero.</p>
+                </li>
+                <li>
+                    <code>subtract-overlap</code>
+                    <p>Inverts the amplitude of every even-numbered channel and merges all channels to mono. This effectively cancels the sounds the left and right channels share in common. Quick-and-dirty way of removing vocals.</p>
+                </li>
+            </ul>
+
+        </div>
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