Visual Nexus has a very high quality broadband audio system and you should have excellent audio quality in your calls.  However, a number of different things things can effect the quality of the audio.  The main symptoms are listed below with recommended solutions.

I can hear an echo of myself in a call

Visual Nexus has an inbuilt echo cancellation system, but this must be selected when you calibrate the audio during setup.  If you can hear an echo of yourself during a call then one of the other participants in your meeting has not set echo cancellation correctly.  Remember that they will not be able to hear this echo.  The easiest way to find out who is the "offender" is for each person on the call to mute their audio in turn and then to listen for when the echo stops.  That person causing the echo will then need to hang up from the call, select endpoint configuration and re-run the audio setup wizard with echo cancellation set.

The audio is "clipped"

Some microphones and web cams also have an echo cancellation feature.  If both the echo cancellation in the microphone and that in Visual Nexus are turned on, then there is a chance they will compete with each other, resulting in clipped audio.  In this case you must turn off one of the echo cancellations.

The audio is breaking up or distorted

Your computer is doing a lot of work to encode and transmit the audio stream. If you have a less powerful computer you may find that it is running at close to 100% of its CPU capacity.  In this case the audio may break up or become distorted.  We also sometimes see this if your browser is left pointed at a web page with lots of animation it.  The solution is to close other programs on your computer to provide more computing power to Visual Nexus.

After a while I get very bad static noise on my audio

This happens occasionally when you are using the microphone in your web cam.  Both the video and audio are being sent over the USB and on some computers the I/O bus overloads and the audio is lost.  It does not effect the video.  We have only ever seen this on notebook computers.  The solution is either to switch to a headset and use the audio system in your computer or to use the inbuilt microphone in your computer.  We have also found that using an echo canceling speaker microphone system such as the Phoenix Duet will also overcome this problem.

The people I call can't hear me

You must be sure that the Visual Nexus software is using the correct microphone.  When you change configurations, from the office to home for example, it is easy to forget to switch to the new audio device settings.  Do this by using the audio wizard in the endpoint configuration system.  Remember that for best audio performance you should rerun the audio wizard whenever you change speakers or microphones

When I calibrate the audio its fails

This can happen if you have not set the audio system to use the correct microphone.