Updated 06/17/2009

Many people seem to have sound issues. First off, if do NOT have Vista Service Pack 2 (for Vista), then install it. It has solved the problem for many people already, particularly the problem where game characters have high voices.

Vista 32 bit SP2: [url:1h1waa0a]http://www.microsoft.com/downloads/details.aspx?FamilyID=a4dd31d5 -f907-4406-9012-a5c3199ea2b3&DisplayLang=en[/url:1h1waa0a]
Vista 64 bit SP2: [url:1h1waa0a]http://www.microsoft.com/downloads/details.aspx?FamilyID=656c9d4a -55ec-4972-a0d7-b1a6fedf51a7&DisplayLang=en[/url:1h1waa0a]


If that does not do the trick, then try changing the hardware accelaration . It has been reported that it needs to be set to around 44100 Hz to fix it, 48000 is still too high.
In vista to find this, you right-click the speaker in lower right, select Playback Devices, find your soundcard in the list, right-click and choose properties, go to advanced tab, in the Default Format dropdown list choose 16 bit, 44100 Hz (CD Quality) or 24 bit, 44100 Hz (Studio Quality).
In XP to find this, Click START, Settings, Control Panel, Sound and Audio Devices, Speaker Settings, Advanced, Performance, and change the hardware accelaration there.

When you have no sound at all, then try disabling AGP in the dxdiag (start, run, dxdiag, sound tab)

Also make sure your sound drivers are up-to-date.

Another suggestion, by alx_mercer, which worked for everybody with xp sp3 so far, is to disable modem audio devices in the device manager.

Removing the 00audio.rcf file, as is suggested in this thread, only works temporarily, upto chapter 3. After that the bad sound reoccurs. Also people have reported that removing the file gets them stuck, so better leave that file in place. It's there for a reason. There must be a better solution.


Below are the suggestions of the official tech help:

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Make sure you have the latest video and sound card drivers from the manufacturers' websites.


All background applications must be shutdown prior to running the game.


Turn the hardware acceleration for your sound card to Basic.
1) Click the Start button > Settings > Control Panel.
2) Double-click on the Multimedia icon.
3) Select the Audio tab.
4) Click on the Advanced Properties button in the Playback section.
5) Click on the Performance tab.
6) Reduce the Hardware acceleration to Basic, the 2nd notch from the left.
7) Click Apply and then OK 2 times. Run the game now. Don't forget to turn the acceleration back up to restore the high-end features for your sound card when using other applications.

NOTE: For Windows XP
1) Click the Start button > Settings > Control Panel.
2) Double-click the Sounds and Audio Devices icon.
3) Click the Volume tab.
4) Under Speaker settings, click the Advanced button.
5) Click the Performance tab.
6) Reduce the Hardware acceleration to Basic, the 2nd notch from the left.
7) Click Apply and then OK 2 times. Run the game now. Don't forget to turn the acceleration back up to restore the high-end features for your sound card when using other applications.

If you are using Windows Vista please check to verify that your default sound format is not set too high:

Start menu -> Control panel
Double-click on Sound
Locate your default sound device, it will have a green check
Right-click on this device and select properties
Select the Advanced tab
Look at the Default Format drop down menu.  If this value is set above 48000 Hz (regardless of bit rate) please change the setting to a lower setting. 
Hit ok and close the sound and control panels
Try the game again

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If the issue still persists, then post below which Operating System exactly you have, attach a dxdiag and describe the exact sound problem.