Foreword: The EDC3 is NuForce's (and Massdrop's) solution to a neutral IEM in the $100 bracket, a position that that really has only been tapped by Hifiman and their lower end RE series and Etymotic's HF/MK series. Special thanks to @CEE TEE for graciously providing me a sample upon my request. Frequency Response Mostly neutral tuning, following a pinnae compensation more-or-less as opposed to diffuse-field/HRTF. Treble doesn't sound as prominent as on raw IEC, but also not as rolled off as the anti-resonance coupler would suggest. @purr1n's graph is more accurate in this regard. Impulse (Still trying to get as much data as I can on impulse response, but so far there seems to be a correlation between impulse and supposed "cleanliness" or "speed" of the sound output.) CSD No time domain coherence issues here. THD Ignore the bass weirdness on the left channel, there's some roadworks outside just as I swapped channels. Strong third harmonic dominance, as expected. The EDC3 in particular has a strong plasticky crispy timbre (BA timbre for the uninitiated) to my ears, which doesn't really make it the most natural sounding IEM in my collection right now. Impedance Reactivity Should be relatively unchanged by system output impedance. Tested with my 75ohm resistor adapter; definitely sounds different but it's nowhere near as drastic as other sensitive IEMs. Additional notes: Staging is a glaring weakness in the EDC3. Everything is in-your-face and 2-dimensional, it's not going to be a good match for orchestral genres that's for sure. As mentioned above, slight timbre issues. Vocals dominate my music library so this is probably more sensitive for my kind of use cases. HOWEVER, its kind of neutral presentation is unique in its price range. It sits in a nice niche position against Hifimans (bright-neutral) and the cheaper Etymotics (diffuse-field neutral).