I have always hated how you can hear Zombies through solid walls and how you can hear thunder when working away down at bedrock.
Well I have found a solution, there is a nice mod called Better Sound or BSM, and all it does is improve the way minecraft handles the way sounds are generated and also adds some cool effects.
The big one is it dampens the sounds as they pass through blocks so it gets quieter faster, so you can't hear zombies through walls unless your beside the block and he is on the other side, and rain is MUCH quieter when you go indoors.
You can find the mod here to test out (bear in mind there is a few things todo to install it which are outlined below)
[1.4.6][SSP/SMP] BetterSound Mod (BSM) [Alpha-v0.0.15] - Minecraft Forum
To install it I recommend putting a z at the beginning of the name so it loads last and then put the zip file in the instMods within your Mindcrack folder
But as Sor just posted we aren't allowed to use it when connecting to our servers without it being on the approved list, so I hereby submit it to be considered for approval (which I forgot to do before trying it on the FTB server, my bad, I thought it was a testing server so testing a mod would be cool but its not)
I have now tested it thoroughly on my single player server and it rocks and seems to work fine with Mindcrack and I have now disabled it pending approval.
To install it you need to update your LWJGL because the one that comes with minecraft is WAY WAY out of date and doesn't have the cool sound effect stuff used by this mod, the updated version is also better performing I believe so it should have an improvement with performance too.
You can get 2.9.0 at http://www.newdawnsoftware.com/jenki...wjgl-2.9.0.zip
And then you can follow the instructions here
Note: Backup any files you are replacing in case the update fails
Now, locate the pack you want to update. Since each pack is its own instance, you'll need to update the lwjgl for each pack. Open the ZIP file, then open the lwjgl 2.8.4 folder. The only important folders here are jar and native. You can ignore the rest.
Open the jar folder and replace the files in your bin folder with the following:
It should ask if you want to replace the old files. Hit yes!
Then, go back to the ZIP folder and go to the native folder. Here, you will see folders for windows, linux, mac, etc. I've heard of possible issues with mac and this version of lwjgl, so back up your current ones before updating. Take all of the files inside the folder for your system and replace them inside the natives folder inside your bin folder.
Tada! You've updated your lwjgl! I used to have a sound problem whenever Minecraft started up that would eventually go away, but updating fixed everything!