 only the k‑rate node’s target param to k‑rate
          // automation
          const kRateParam = kRatePanner[param.name];
          kRateParam.automationRate = K_RATE;
          assert_equals(kRateParam.automationRate, K_RATE,
              `${param.name}.automationRate should be k‑rate`);

          // Identical automation on both nodes
          [kRatePanner, aRatePanner].forEach(panner => {
            panner[param.name].setValueAtTime(param.initial, 0);
            panner[param.name].linearRa