Touch response is also known as touch sensitivity. This technology simulates the process of sound generation in chordophones (example pianos, violins and guitars) which are sensitive to the velocity of key press. In simple terms, the harder you press the keys on a keyboard the louder the sound produced. Press the keys lightly and a softer sound will result. If a keyboard doesn't come with touch response, it means that no matter how hard or how light you play, the volume won't be affected. Touch response is a much desired feature in musical keyboards.
