OK, basic netcode related commands explained as I understand them:
rate and cl_rate are the number of bytes/sec worth of bandwidth you have available for download and upload, respectively. Just set cl_rate to 9999 (which is all it will let you set it to anyway) and rate to 20000.
Cl_cmdrate and cl_updaterate are updates per second from client -> server and from server -> client, respectively. Cmdrate can be set about as high as you want, it won't really hurt anything. Anything above 75 or so for cl_cmdrate probably wont' have any effect at all, but it won't really hurt anything either.
Cl_updaterate on the other hand has to be carefully tweaked, because it works hand in hand with ex_interp. Ex_interp interpolates frames of movement inbetween actual frames of movement that you get from the server. Ex_interp at the moment isn't supposed to be changeable, and it's locked at .1. Correct ex_interp should be 1/cl_updaterate. So this interp is good for a cl_updaterate of 10 and nothing else. Bear this in mind when you start upping your cl_updaterate. That said, a cl_updaterate anywhere from 15 up to 30 should work fine on most servers, depending on how you ping to them. The trick is to open up a net graph and adjust until you're no longer getting choke and don't have a lot of extra lag showing next to your updaterate (net_graph 3... I think... is the one that shows you this on the top line). Then once you've adjusted your cl_updaterate, you'll probably want to adjust your ex_interp as well. (1/cl_updaterate remember. So an updaterate of 20 would need an ex_interp of .05. You'll know if you're fooling yourself with an updaterate that you can't support if everyone appears to be jerking around madly... you're not getting as many updates from the server as you think you are, and your client isn't interpolating enough extra 'fake' movement frames... you've told it not to, thus, jerky players) It's possible to change ex_interp, but you have to alias it immediately afterwards. As in type "ex_interp .05" in console, immediately followed by "alias ex_interp". You won't be able to change it again, but it won't be immediately changed back either.
Now that all that's out of the way, does it make no sense at all?
I'm not sure if any of these commands will help with your screwy voice, but it's worth a try. Turn on your netgraph anyway. Getting a lot of choke? Loss? Lots of lag showing? We'll figure it out, if it kills... uh... Grimm.