The storage disk media substrate effect on contact/clearance sensor, also named embedded contact sensor (ECS), is addressed in this paper. The ECS exhibited different response on storage media comprising Aluminum and glass substrates. The response is attributed to cooling efficiency from the disk during a touchdown event. Aluminum substrates provided more effective cooling to the ECS as be measured by the DC component of the ECS signal. The AC component of the ECS signal was found to be less sensitive to media substrate than the DC component. The response dependence on bias applied to the ECS has also been characterized. Aluminum substrates showed larger sensitivity to bias compared to glass. By tuning the bias, both the AC and DC signals from ECS can be utilized as effective touchdown detectors.