This includes transient intermodulation distortion (TIM). The beginning and ending transients of musical sounds are largely what determine their timbre, rather than their harmonic content. An audio device which passes steady-state signals perfectly well may distort the loud, high-frequency transients, causing audible coloration of the music. Low transient distortion means a device must have a wide, linear frequency response, no phase distortion, and no hangover. TIM is caused by amplifier slew-limiting and is principally a problem in solid-state amplifiers that use large amounts of negative feedback.