A transient multi-tone test signal is generated to detect piano noise distortion played back by a speaker. The test signal has a number, such as three, formant tones resembling a piano chord and selectable such that the frequencies and harmonics remain distributed in frequency. The test signal provides a basis for defining normal speaker operating performance and allows a user to define speaker responses that fall outside of normal boundaries by highlighting piano noise distortion detected during speaker playback of the test signal.