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Solution:

Integrated VoIP enables meeting hosts, trainers, or event producers to use the Internet (or a private IP network) to deliver the voice aspect of a meeting, live online training or large event. Rather than using a traditional audio conference, participants use headsets and speakers connected to their computers to participate in the audio portion of the meeting. Many VoIP solutions experience delay and quality issues when compared to traditional audio conferencing.

Integrated VoIP capacity limits:
 

Wideband Audio (HD Voice)

Enhanced audio experience with much better audio quality than standard narrowband VoIP

• Wideband Audio is the new default standard for Webex VoIP attendees.
• Windows, Mac, and Linux desktop clients, iOS and Android mobile devices are all supported
• Both VoIP and Hybrid Audio support wideband audio
• Uses the Opus audio codec

Not supported on Wideband audio:

• Desktop Solaris and Windows mobile devices
• If any of the unsupported devices joins into the meeting, VoIP audio for all participants will switch to lower-quality narrowband standard VoIP
   

Microphone Allocation:

See the following article to check your Webex site version: Finding Your Webex Version Number

• Up to 500 microphones are automatically allocated (including the host).
• Only the 3 most active audio streams will be mixed.

• Conduct a dry run so the presenter(s) can determine the correct sound levels.
• It is highly recommended to send an audio file to the attendee machines to test audio prior to the event starting. This can be done in the invite or by pushing an audio file to the attendees when the meeting starts.
• Be aware of the supported system requirements for Wideband audio. If a Windows mobile users join the conference, audio quality will degrade to standard narrowband audio

Guidelines to follow during VoIP session:

• Avoid playing music over an active VoIP mic.
• Avoid background noise.
• Always encourage speakers to use a headset, as they provide better quality than many PC microphones. PC microphones are very sensitive and tend to pick up background noise. In addition some environments/configurations provide a high gain feedback loop between the mic and the speaker. This can overwhelm the built in echo cancellation and create a feedback loop which will cause a loud echo.
• Always use the headset profile for all meetings.
• Mic levels are set automatically. This setting can be manually overridden using the VoIP setup wizard. It is recommended that the default Automatic Gain Control and Echo Cancellation settings are not changed.
• Speak slowly and avoid speaking during slide transitions. This will help manage bandwidth utilization and minimize network congestion.