It is possible to choose the starting phase of a pure tone in a way that minimizes the onset noise when the tone is turned on abruptly. A spectral model shows that when the tone has a low frequency, minimum onset noise is expected for a starting phase of zero (turning on a sine tone) but when the tone has a high frequency, minimum onset noise is expected for a starting phase of ±90 deg (turning on a cosine tone). Listening experiments confirm the above expectations and show that the transition between low‐ and high‐frequency domains is sharp and depends upon both the electroacoustical transducer and the individual listener.