Sympathetic vibration in a piano

Sympathetic vibration is a common phenomenon in musical instruments. In the piano, strings that are not struck directly by the hammer can vibrate sympathetically due to physical coupling. This effect will, for instance, occur when the una corda pedal is used in a grand piano. When depressed, the hammer shifts rightwards so that the leftmost string will be missed, striking only 1 out of 2 (or 2 out of 3) strings in a note at a same time. In order to understand the acoustical and perceptual differences in the notes played without and with una corda pedal depressed, the recordings of a piano for these two playing conditions are studied for all 88 keys. Differences arising in the frequency domains are found and presented alongside with discrepancies in three psychoacoustical descriptors, namely log-attack-time, temporal centroid and normalised spectral centroid. Future work in the form of listening test is planned.