Overall, both headphones are feature-rich and cater to users looking for a combination of sound quality, comfort, and wireless convenience. If you're comparing Audio Technica ATH-ANC9 and Denon AH-MM300, both models offer a strong combination of sound performance, comfort, and modern wireless features. There is a noticeable difference in weight (220 g (Inclusive of Battery and Cable) vs 195 g), which may affect comfort during extended use. Both models support modern Bluetooth connectivity, ensuring stable wireless performance with compatible devices. Both headphones offer solid battery performance, making them suitable for long listening sessions and travel. Both headphones are equipped with capable drivers that deliver balanced sound output suitable for music, calls, and entertainment. The frequency response differs (10 - 25,000Hz vs 10 Hz - 40,000Hz), which can influence how well the headphones reproduce lows, mids, and highs. Audio Technica ATH-ANC9 and Denon AH-MM300 offer different noise cancellation capabilities (Yes (Reduces Noise up to 30 dB) vs NA), which can impact how effectively they block external noise. Impedance levels vary (100 ohms (when noise cancelling function is used) vs 32 Ohms), which can affect compatibility and audio output when used with different devices.

Verdict: Choosing between Audio Technica ATH-ANC9 and Denon AH-MM300 depends on whether you value better sound, longer battery life, or enhanced features.