Foreword: The King Pro is TFZ's $170 DD offering, meant to be a step up from the TFZ King. Frequency Response I'd classify it as a U-shaped signature. You have a bass boost that's, for the most part, concentrated mostly in the sub frequencies. Plus a 9k boost that gives good bite to sharp percussions. The relative lack of lower mids does make it sound more thin than I'd like. Vocals do sound like they're keeping their distance. Impulse Pretty clean impulse. Maybe a little too much linger at the end but eh, nothing sounds wrong to me. CSD THD THD values to be expected. Not the lowest but well within expectation. Impedance Reactivity Does not react to changes in Z-out. Additional notes: The <$200 space is an odd place for IEMs. Doesn't really appeal to the budget minded people but also won't turn heads for the highballers, both being the biggest populace of the IEM community. The signature is not for everyone. Pretty intense U that pretty much shits itself on acoustic and classical pieces. It's a mainstream tuning I guess, works for pop and EDM.