Key Differences

Sennheiser HD-451 and Sennheiser HD 400S are premium wireless headphones designed to deliver high-quality sound along with advanced features like noise cancellation and long battery life. There is a noticeable difference in weight (380 g vs 217 Gm), which may affect comfort during extended use. The frequency response differs (20 Hz-20,000 Hz vs 18 Hz -20000 Hz), which can influence how well the headphones reproduce lows, mids, and highs. The driver size differs between the two (NA vs 9.7 mm), which can influence sound depth, bass response, and overall audio clarity. From a usability standpoint, both models provide a reliable and premium headphone experience. Both headphones offer solid battery performance, making them suitable for long listening sessions and travel. Both models support modern Bluetooth connectivity, ensuring stable wireless performance with compatible devices. Sennheiser HD-451 and Sennheiser HD 400S offer different noise cancellation capabilities (Yes vs AMBIENT), which can impact how effectively they block external noise. Impedance levels vary (32 Ohms vs 18 ohm), which can affect compatibility and audio output when used with different devices.

Verdict: Both models are competitive, and your decision should be based on your usage needs and preferred features.