
        // Create the graph.  The output of iir1 (normalized coefficients) is
        // channel 0, and the output of iir2 (unnormalized coefficients), with
        // appropriate scaling, is channel 1.
        let merger = context.createChannelMerger(2);
        source.connect(iir1);
        source.connect(iir2);
        iir1.connect(merger, 0, 0);
        iir2.connect(gain);

        // The gain for the gain node should be set to compensate for the
        // scaling of the coefficients.  Since iir2 has 