The in-ear monitor sound of the IE 400 PRO delivers a noticeable punch, clear highs, and transparent mid-range reproduction. Even at high sound pressure levels, the IE 400 PRO reproduces its warm sound without artifacts or distortion. With the developed TrueResponse technology, the 7 mm dynamic driver achieves an enormous resolution and avoids acoustic stress even during prolonged use. Common issues like distortion, overlapping frequencies, and resonance peaks are no longer a problem. The total harmonic distortion is optimized to an previously unimaginable 0.08%. The ultra-compact design can be individually adjusted thanks to the included silicone and memory foam adapters. Easy to handle, brilliant in sound, robust even under extreme conditions, and securely and comfortably fits in the ear canal for hours.