These measurements were collected over a number of years so there might be some variations in cassettes and levels used. For the majority of decks the Sony Metal XR C60 cassette and 10kHz signal at about -10 ... -20dB DIN was used. The graphs are scaled so 0dB corresponds to the maximum level and the modulation noise is shown relative to the signal level. The frequency range on the graphs is from 7.5kHz to 13.5kHz .