In general, higher sound quality consumes more bandwidth and greater server CPU utilization by sending more audio data to user devices. Sound compression allows you to balance sound quality against overall session performance; use Citrix policy settings to configure the compression levels to apply to sound files.
Consider creating separate policies for groups of dial-up users, and for those who connect over a LAN or WAN. Over dial-up connections, where bandwidth typically is limited, users are likely to care more about download speed than sound quality. You may therefore want to create one policy for dial-up connections that applies high compression levels to sound, and another for LAN or WAN connections that applies lower compression levels.
You can allow users to receive audio from an application on a server through speakers or other sound devices (such as headphones) on the user device. By default, Client audio redirection is Allowed.
Client audio mapping may cause a heavy load on the servers and the network; to turn off this feature, add the Client audio redirection setting to a policy and set its value to Prohibited.
You can allow users to record audio using input devices such as microphones on the user device. By default, Client microphone redirection is Allowed; however, if audio is disabled on the client software, or if Client audio redirection is Prohibited, this setting has no effect.
To record audio, the user device needs either a built-in microphone or a device that can be plugged into the microphone jack or USB port. For security, users are alerted when servers that are not trusted by their user devices try to access microphones, and can choose to accept or reject access prior to using the microphone. Users can disable this alert on Citrix Receiver.
To turn off this feature, add the Client microphone redirection setting to a policy and set its value to Prohibited.
The Audio redirection bandwidth limit policy setting specifies the maximum bandwidth (in kilobits per second) for a playing and recording audio in a session. The Audio redirection bandwidth limit percent setting specifies the maximum bandwidth for audio redirection as a percentage of the total available bandwidth. By default, zero (no maximum) is specified for both settings.
To configure the Audio redirection bandwidth limit or Audio redirection bandwidth limit percent or both, add the setting to a policy and type a number in the corresponding Value field. If both settings are configured, the one with the lowest bandwidth limit is used.
By default, Audio over UDP Real-time Transport is Allowed, opening up a UDP port on the server to support all connections configured to use Audio over UDP Real-time Transport. Citrix recommends configuring UDP/RTP for audio, to ensure the best possible user experience in the event of network congestion or packet loss.
By default, UDP audio on XenDesktop uses two consecutive ports within the range of ports 16500 to 16509 to pass through the Windows firewall; the default ports are 16500,16501. To use other ports, add the Audio UDP port range setting to a policy and type the port number or range (in the form lowest port number,highest port number) into the Value field. This setting specifies the range of port numbers used by the Virtual Delivery Agent (VDA) to exchange audio packet data with the user device. The VDA attempts to use each UDP port pair to exchange data with the user device, starting with the lowest and incrementing by 2 for each subsequent attempt. Each specified port handles both inbound and outbound traffic.
When users take part in audio or video conferences, they may hear an echo in their audio. Echoes usually occur when speakers and microphones are too close to each other. For that reason, Citrix recommends the use of headsets for audio and video conferences.
HDX provides an echo cancellation option, enabled by default, which minimizes echo during a conference. The effectiveness of echo cancellation is sensitive to the distance between the speakers and the microphone. These devices must not be too close to each other, or too far away from each other.
To disable echo cancellation: