[clug] Bad echo when using gnome meeting

Michael Still mikal at stillhq.com
Mon Jun 14 10:31:12 GMT 2004

Alex Satrapa wrote:
> On 5 Jun 2004, at 14:05, Michael Still wrote:
>> Anyways, I get a really bad echo of my own voice when testing it. 
>> Playing with the echo correction options doesn't seem to effect it...
> Is is possible that the echo is due to an omnidirectional mike picking 
> up your voice bouncing off the walls/ceiling/floor? If you can, find a 
> unidirectional noise canceling mike such as the Platronics one that 
> comes with Microsoft GameVoice. Physical (ie: mechanical) noise 
> canceling is, IMHO, much more effective than electronic - but that's not 
> the issue here. The key feature is "uni-directional", a great addition 
> is "noise-canceling".

I'm using a logitech headset microphone thingie, I can't imagine echo is 
a big problem. No where near the scale I'm experiencing at least.

> Have you also checked the obvious things like not having the sound card 
> in full-duplex mode, muting the microphone in the output mixer, and 
> using only the microphone as an input source?

Yeah, I've checked all of those...

>> Does anyone have any hints about what I might be doing wrong?
> ... and make sure you're not trying to use GnomeMeeting from your 
> wireless laptop while on the loo, since you're going to need some rather 
> advanced signal processing software to cancel out *that* echo!

It was actually two wireless laptops in the same room. I believe in 
pushing the technology.

>> Also, I seem to recall reading that H323 is evil to proxy... What is 
>> the best way of getting destination NAT like functionality for H323 
>> (should I be using a redirector out on the big bad internet?)?
> For VoIP services, you need a gatekeeper. This is basically a proxy - it 
> has to be visible from both the internal network and the Internet. An 
> alternative to a gatekeeper is a conferencing server. Check out 
> opengate, openh323gk or openmcu.

Does iptables do connection tracking for H323? The scenario is random 
machine on the internet talking to a machine at home via dnat.



Michael Still (mikal at stillhq.com) | "All my life I've had one dream,
http://www.stillhq.com            |  to achieve my many goals"
UTC + 10                          |    -- Homer Simpson

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