There is a noticeable difference in weight (250 g vs NA), which may affect comfort during extended use. Both models support modern Bluetooth connectivity, ensuring stable wireless performance with compatible devices. The frequency response differs (5 Hz - 35000 Hz vs 10 Hz - 25000 Hz), which can influence how well the headphones reproduce lows, mids, and highs. Both models feature noise cancellation, helping reduce background noise for a more immersive listening experience. In general, both options are suitable for everyday use including music, calls, travel, and work-from-home scenarios. Both headphones offer solid battery performance, making them suitable for long listening sessions and travel. If you're comparing Beyerdynamic DT 990 PRO and Koss PRO-4AA, both models offer a strong combination of sound performance, comfort, and modern wireless features. Both headphones are equipped with capable drivers that deliver balanced sound output suitable for music, calls, and entertainment.

Verdict: Both headphones offer strong performance, and the right choice depends on your priorities such as battery life, comfort, and noise cancellation.