I've done (graphics) tweaks for 10 years now in Crysis, I'm pretty sure this sound problem can also be solved with a custom configuration. I haven't tried it myself yet because it's already working for me with the in-game settings. But the solution below should theoretically work.
Lookup the installation folder of Crysis (where CrysisLauncher.exe is located, not one of the bin folders). Make a new text file in notepad and save it as autoexec.cfg (you need to change "save as" to "All filetypes".
Place/save the new autoexec.cfg in the Crysis folder you just located.
We're going to add a few commands / tweaks into the just created configuration file. You can copy past the commands between the horizontal lines below (don't copy the lines).
; User Options commands
con_restricted = 0
r_displayinfo = 0
s_SoundEnable = 1
s_SpeakerConfig = 5
con_restricted disables the use of advanced commands (default), by setting it to zero you disable this restriction.
r_displayinfo show additional (debug) information during the game. We want to disable this so we set it to 0.
s_SoundEnable Enables sounds. It's probably not required to include this command but since you're having sound related issue's it might be worth a shot. So we set it to 1. (It should work perfectly without this command.)
s_SpeakerConfig has 8 possible values. It tells the game to use a specific speaker setup. This is the command where it's all about. Because most people use a 5.1 speaker configuration I've set it to 5 but other values are possible too.
0 = Default system setting
1 = Mono
2 = Stereo
3 = Headphones
4 = 4.1
5 = 5.1
6 = Prologic
7 = 7.1
If the above solution doesn't work rename the autoexec.cfg to system.cfg (some commands only work in a system.cfg instead of a autoexec.cfg).
There's a lot you can do with tweaks in such a file.
There are many configurations that alter graphics and such. If you want to tweak more I would recommend reading guides like this one: http://www.tweakguides.com/Crysis_1.html
Over the years I've created a collection of great tweaks and commands. If anyone's interested let me know. :)
Well, I've installed Crysis 1 recently and since I tweak pretty much every game before even playing it then I went through forementioned tweakguides guide ( before seeing this post :P ).
I would like to add that there should b no spacebars in commands. So it shouldn't be like " con_restricted = 0 " just " con_restricted=0 ". Also forementioned tweak guide mentions that system,cfg contains the commands to b executed on GAME-ENGINE STARTUP and the autoexec.cfg contatins those to b executed AFTER game-engine loads. If I would hv some sound issue then I would place all ur commands in both files just to b sure that game doesn't skip anything.