Stevens used magnitude estimation to establish the mel scale. The pitch of 1000 Hz is 1000 mels. A sound that sounds half as high would have a pitch of 500 mels, while a sound that sounds twice as high would have a pitch of 2000 mels. Notice that the frequency that is twice as high as 1000 Hz is 3120 Hz and the one that is 3 times as high is 9000 Hz. The relationship between frequency and pitch is not simple.