Please note: This article is written for Steam games that run the Half-Life 1 engine! Source engine based games do not use the same commands or codecs mentioned below; therefore, this article does not apply to them. As of March 12, 2007, all Source based games (by default) will be using the vaudio_speex codec which is designed to make microphone quality much better than it was in the past. If you converted your .wav files correctly, they should sound fine in Source based games.
Sometimes you may notice that a wav doesn't sound very good while being played over the microphone. The problem is almost always on the server's end, NOT YOURS!
Many server owners don't know that they can increase the sound quality for all voice communication on their server with a few simple rcon commands. And best of all, this won't cause the server any lag.
The 2 rcon commands are:
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sv_voicecodec voice_speex
sv_voicequality 5
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On the second rcon command listed above, you can set the number 5 from 1-5 with 1 being the lowest sound quality, 5 being the highest.
ALL 5 LEVELS use LESS BANDWIDTH than the default voice codec that is enabled on servers (which is voice_miles), so there's no reason why every server shouldn't change their voice codecs immediately. Levels 2-5 also have BETTER quality than the default codec miles! The miles codec only has 1 level that can't be changed either.
Here are the technical specs of the codec voice_speex in case you are interested:
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» Level 1: 6 bytes/frame, 2400bps, lowest quality
» Level 2: 15 bytes/frame, 6000bps
» Level 3: 20 bytes/frame, 8000bps
» Level 4: 28 bytes/frame, 11200bps
» Level 5: 38 bytes/frame, 15200bps, highest quality
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So what can you do now? Go to your favorite servers and see how the voice quality is. If its really fuzzy and choppy tell a mod, or even the owner that they can increase the quality with those 2 rcon commands listed above. Placing the commands in their server.cfg file will also execute the commands automatically when the server starts up so there is good quality the next time the server has to reboot. These commands will make the voice communication sound a lot better, and it uses less bandwidth!
How does it use less bandwidth? - The speex codec was designed to utilize more of the server's CPU for processing voice communication. It will increase the amount of CPU cycles on a server, but will cut back on bandwidth at the same time! Admin's don't need to worry about using up more cpu power either... the speex codec only uses 1 - 2% more from tests done at VALVe (according to their Support pages)!
I hope this article clears of some any confusion you may have about voice codecs or sound quality. Have fun!
This article was last updated March 13, 2007. 
