I think Turkish Delight nailed it. Use the Very Best NC H/S you can find and sell the wife if necessary. Take very good care of it and protect it. Bose is a great place to start, but others may serve you better. For best audio and hearing protection, fully enclose both ears ALL the time. (Use audio panel adjustments to comm with partner if possible, or insert foam plug if center ear must be left uncovered.) And sadly... if necessary at your company, pay a few extra bucks with your periodic medical exam for a complete audio test, always kept private. If the hearing starts to go, make them pay.
The most important protection, regardless of AC type, is to protect BOTH ears all the time. If you do walk-arounds, use foam plugs. If you set up the driver's seat, get your headset on, perhaps with an open mike, as soon as you sit down. Been there and paid the price.
