Don't know in dB's but I'm reliably informed that the (new) Airbus is significantly quieter than the Boeing 737 NG. I fly the Bus (never flown Boing) and I also use an ANR headset - and it's a very comfortable working environment, even on a 4 sector day. I used to fly the older 'Bus and the flightdeck ventilation in the newer one's is significanlty quieter....but you do get cold feet on longer sectors!
A4