I will be travelling very soon and need a headphone for travelling, taking phone calls and office work. Although not a fan of BT ANC headphones, have listened the momentum 4 at bestbuy and compared to other BT ANC headphones for 3 hours today, and a 100 discount, placed the order after. At home, I continue testing the moment 4 on wired mode since I have my laptop, the AK kann alpha DAP and Chord hugo 2. Here is just my sound impressions. Not professional reviewer so bare with me some words.
Under wireless mode, very good sounding headphones. Certainly not as good as bathys. But it is very close. The stock tuning has too much bass. Once crank down from the app, it sounds perfect. Everything is detailed, balanced. The modified tuning from the phone will carry to other BT devices like my Kann alpha, laptop. However, even running aptx hd on my Kann alpha, personally they almost sound identical from my iphone, laptop, kann alpha using BT.
Under wired mode with USB C. The sound even opened up, and more separation. the bass is reduced to acceptable degree. Certainly the internal dac will improve the sound quite well.
Under wired mode with headphones on, it does not meet my expectations. The internal dsp seems don't like powerful and better analog signal feed though the cable. When connect to kann alpha and chord hugo 2 using wired connection, the sound will start to distort and crack above say 70 db.
Edit: this problem fixed after cranked up the volume in the right ear cup. On hugo 2 again, no more distortion found, and it sounds superb. The best sound 300 dollar headphone you can buy. It competes even with focal Celestee.
Under wired mode with headphones off, it sounds the worst. the headphone will get louder when connect to kann alpha and chord hugo 2, but it sounds hollow. It just like play a speaker in the cave.
When connect to wired mode, the better analog signal can't bypass dsp circuirtary limit the momentum 4 sound even better. As an audiophile, I don't expect sound as good as Celestee, but it should sound at least better than wireless or usb c mode.
I won't travel with bathys, but momentum 4, certainly will. So far quite happy with my purchase.