i*sqrt(-d)/2.  Thus the magnitude of each
          // root is the same and is sqrt(a1^2/4 + |d|/4)
          let d = Math.sqrt(-discriminant);
          return Math.hypot(a1 / 2, d / 2);
        } else {
          // Real roots
          let d = Math.sqrt(discriminant);
          return Math.max(Math.abs((-a1 + d) / 2), Math.abs((-a1 - d) / 2));
        }
      }

      audit.define('4th-order-iir', (task, should) => {
        // Cascade 2 lowpass biquad filters and compare that with the equivalent
       