ut.

        // The filter is y(n) + c*y(n-1)= x(n).  The analytical response is
        // (-c)^n, so choose a suitable number of frames to run the test for
        // where the output isn't flushed to zero.
        let c = 0.9;
        let eps = 1e-20;
        let duration = Math.floor(Math.log(eps) / Math.log(Math.abs(c)));
        let context = new OfflineAudioContext(1, duration, sampleRate);

        // Use a simple impulse as the source
        let buffer = context.createBuffer(1, 1, sampleRate);
   