Yeah, the sound in this game is ground breaking - if everything sounds the same, you're definitely missing out!!

Originally Posted by Matthew Harwood - Audio Director

Delay and distance sounds or Level of Detail (L.O.D.) is what I am most excited about with the sound in our game. It’s something that no other game is doing to this extent. The delay of gun fire and explosions is simple. When you see the flash of an explosion in the distance you will not hear it right away. There is a delay based on distance, the farther away the longer the delay. We originally did the math at 769mph or 1128ft/s (the speed of sound). You would be surprised how long of a delay at such short distances this math provides. So we speed up the delay system so you can hear the audio sooner and get the feedback, it is definitely noticeable and very fun.

The other aspect is the distance sounds and this feature is what I am really excited about. Each weapon and vehicle weapon (some vehicle engines - jets and helicopters) and explosions has unique sounds based on the distance and location from the player. So weapons have three distinct sounds. When firing from your perspective (in the first person), you hear a fat, stereo-widened image of the sound. This sound has the most detail and clarity. When you are close to the weapon firing (the weapon in the third person), you will hear a mono positional sound with slightly less detail then the first version. Then there is the distant sound that you hear when the weapon is fired far away from you. The blast of a close tank shell, thumps at distance. The roar of the mini-gun growls with mechanized terror when close, but fizzles and roars from far away. Explosions blast with dirt and debris partials when close, and they pop and rumble at a distance.

I worked very hard to give each weapon a distinct feel and sound. If you spawn into a multiplayer match and stand there for a sec, you should be able to tell which weapon loadout the enemy is firing at you. The truly awesome result from this system, is now the entire battle field is generating the ambiance of war, naturally, produced by the players. The players are the ones creating the soundscape. You’re not only affecting the gameplay with your loadout and roll choices but are also actively changing the way the game sounds.

http://www.frontlineswar.com/?page=interview-matt