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Table Of Contents
Audio Quality Problems in Cisco Unity Version 3.1(x) and later
Advanced Audio Quality Troubleshooting in Cisco Unity Version 3.(x) and Later
Cisco Unity-CM TSP Wave Gain Utility
Cisco Unity Automatic Gain Control and Registry Settings
Dialogic Voice Card Automatic Gain Control and Registry Settings
Audio Quality
About Audio Quality Problems
Audio quality problems can manifest themselves in a variety of ways, and can be difficult to diagnose and correct. For example, subscribers may report volume differences between messages and system prompts, or report that messages are distorted. Audio quality symptoms may not be present for every subscriber, or consistently appear on every message or every system prompt.
The entire device topology can affect audio quality, both within and outside of the control of Cisco Unity. Cisco Unity-controlled features include automatic gain control (AGC), the Cisco Unity-CM TSP wave gain, and the audio codec chosen for message storage. Cisco CallManager controls the region setting for the audio codec. Finally, the Cisco gateway gain and attenuation settings can also affect audio quality.
Audio Quality Problems in Cisco Unity Version 3.1(x) and later
The most common symptom of audio quality problems in Cisco Unity version 3.1(x) is when the volume of greetings and voice names is higher or lower than the volume of Cisco Unity prompts.
See Table 6-1 for basic corrective action to level all WAV files on the Cisco Unity server to the same value, and then to adjust the playback level if needed.
Table 6-1 Basic Audio Quality Troubleshooting for Cisco Unity Version 3.1(x) Systems
The volume of greetings and voice names is higher or lower than the volume of Cisco Unity prompts.
Only certain greetings and voice names may be affected on a version 3.1(1) or later system, and/or an upgrade to version 3.1(3) or later was recently performed.
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Confirm that the Cisco Unity-CM TSP wave gain playback and record settings are both set to 0.
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For detailed instructions, see the "Set Volume Level Utility" section.
For upgrades from 3.1(2) to 3.1(3) or to 3.1(4), see also http://www.cisco.com/warp/public/788/AVVID/white_noise.html.
Set Volume Level Utility
The Set Volume Level utility allows you to level all WAV files on the Cisco Unity server to the same value, and to adjust the playback level, if needed.
Because automatic gain control is enabled by default in Cisco Unity version 3.1(2c) and later, systems upgraded to 3.1(2c) and later may experience a problem where the existing greeting and name recordings sound louder than new greetings and names recorded after the upgrade.
In Cisco Unity version 3.1(4), a new registry setting, AGCminimumThreshold, was added to control the minimum dB level of an incoming recording that Cisco Unity attempts to adjust. The setting prevents silence in a message and background hiss from being adjusted. The AGCminimumThreshold has a default setting of -45 dB and an allowable range of -35 dB to -55 dB.
To maximize success in resolving or avoiding volume problems, we recommend that you first upgrade to Cisco Unity version 3.1(4) or later, then use the Set Volume utility to match the existing greeting and name recordings to the gain levels of Cisco Unity after the upgrade.
Confirm that you have the latest version of the Set Volume utility by doing the procedure, To download and install the latest version of the Set Volume utility.
The procedure, To adjust greeting and name recordings by using the Set Volume utility, levels all WAV files on the Cisco Unity server to the same value, and provides instructions for adjusting the playback level, if necessary.
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To download and install the latest version of the Set Volume utility
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To adjust greeting and name recordings by using the Set Volume utility
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If you have a Cisco CallManager integration, and the Cisco CallManager region is set to use the G.711 codec, in the left pane, under Administrative Tools, double-click Wave Gain.
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If you have a Cisco CallManager integration, and the Cisco CallManager region is set to use the G.711 codec, start the Cisco Unity Administrator.
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If the volume of the recording is acceptable, you have completed all necessary steps in this procedure.
If the volume of the recording is too quiet, continue with Step 15.
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If the volume of the recording is acceptable, note the Playback Gain value and continue with Step 17.
If the volume of the recording is still too quiet, repeat this step.
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Advanced Audio Quality Troubleshooting in Cisco Unity Version 3.(x) and Later
See Table 6-2 for advanced corrective actions and links to other troubleshooting procedures and information for these symptoms:
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For more information, refer to White Paper: Audio Codecs and Cisco Unity, available on Cisco.com at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_technical_reference_list.html.
Note than unless otherwise specified, all procedures apply to Cisco Unity version 3.1(4) and later.
Table 6-2 Advanced Audio Quality Troubleshooting
Messages and/or Cisco Unity prompts sound distorted.
You are using the G729a codec for message storage and retrieval.
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You are using the G.711 codec for message storage and retrieval.
Confirm that the Cisco CallManager region is set to G.711. Refer to the appropriate Cisco CallManager Administration Guide, available on Cisco.com at http://www.cisco.com/univercd/cc/td/doc/product/voice/c_callmg/index.htm.
Hissing noise is heard when there is no audio from Cisco Unity, such as between system prompts or during transfers.
You are using IP phones.
Check the Cisco Unity comfort noise registry setting. See the procedure, To view and adjust the Cisco Unity comfort noise registry setting.
For upgrades from 3.1(2) to 3.1(3) or to 3.1(4), see also http://www.cisco.com/warp/public/788/AVVID/white_noise.html.
Message playback volume is higher or lower than the volume of Cisco Unity prompts, in special cases.
Only outside caller messages are affected on a Cisco Unity system version 3.1(2b) and earlier.
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Both subscriber and outside caller messages are affected system-wide on a Cisco Unity system version 3.1(2b) and earlier.
Check the Cisco Unity-CM TSP wave gain playback and record settings. See the "Cisco Unity-CM TSP Wave Gain Utility" section.
Cisco Unity Is G.729a Capable
When the registry setting HKEY_LOCAL_MACHINE\Software\Active Voice\AVSkinny\G729 Enabled is set to 1, it means that Cisco Unity is capable of receiving both G.729a streams and G.711 streams. It does not indicate that G.729a is in use for message storage. This is the default setting for Cisco Unity version 3.1(x) systems. Because the G.729a codec is installed automatically with version 4.0(1) and later, this registry setting is no longer needed.
To confirm that Cisco Unity is capable of receiving G.729a streams (version 3.(x) only)
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Set Record Format
The Set Record Format utility changes the codec used for all recordings on Cisco Unity. It is not possible to select user or port-specific recording formats. Changes to the record format apply only to recordings made after the change takes place. The utility does not convert any existing messages or greetings to the new codec.
If a Cisco Unity system has been running for a while and the codec is then changed, Cisco Unity may have greetings, voice names, prompts and messages stored in more than one format. Cisco Unity can transcode between formats; however, mixed message formats on very busy version 3.(x) systems have been known to cause the problem described in caveat CSCae08069. For more information, and for a workaround for the problem, refer to http://www.cisco.com/warp/public/788/AVVID/reorder_tone_after_startup.htm. Contact Cisco TAC before installing the workaround.
To view codec information for greetings, voice names, and prompts, do the procedure, To view codec information for greetings, voice names, and system prompts.
To change the codec used for all Cisco Unity recordings (messages, greetings, and voice names) do the procedure, To change the Cisco Unity recording codec.
For information on choosing and implementing codecs, refer to White Paper: Audio Codecs and Cisco Unity, available on Cisco.com at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_technical_reference_list.html.
To view codec information for greetings, voice names, and system prompts
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To change the Cisco Unity recording codec
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To use one of the optional Dialogic OKI ADPCM codecs:
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Click Other Components under Cisco Unity.b.
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To use the optional G.726 32 Kbps codec on a Cisco Unity version 4.0(1) or later system using VPIM with Microsoft Exchange:
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To change the recording format for existing greetings and voice names
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Cisco Unity-CM TSP Wave Gain Utility
The registry keys shown in Table 6-3 determine how the Cisco Unity-CM TSP adjusts record and playback volume for all recordings (messages, prompts, voice names, and greetings) for IP devices in a Cisco CallManager region that contains Cisco Unity and is set to use the G.711 codec.
These registry settings are only applicable with a Cisco CallManager integration. If you have a PBX integration that uses Dialogic voice cards, see the "Dialogic Voice Card Automatic Gain Control and Registry Settings" section.
Use the Wave Gain utility to adjust and test the WaveDBGainPlayback and WaveDBGainRecord levels. The record and playback settings determined by using the Wave Gain utility must be manually entered into the registry by using either the Advanced Settings Tool or Regedit.
For Cisco Unity versions 3.1(2c) and later, set both the Cisco Unity-CM TSP Wave Gain record and playback levels to 0 to begin the volume adjustment process. If you have not already done so, do the procedure, To adjust greeting and name recordings by using the Set Volume utility.
If Cisco Unity automatic gain control is not present (version 3.1(2b) and earlier systems only), then the Cisco Unity-CM TSP Wave Gain playback level setting alone can be adjusted as needed for best sound quality, one or two dB at a time, by doing the following procedure.
To determine the optimum Cisco Unity-CM TSP wave gain settings (Cisco Unity version 3.1(2b) and earlier only)
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When you are satisfied with the volume of the test subscriber message, write down the recording and playback volume settings, which you will enter into the registry in the procedure, To update wave gain settings in the registry for Cisco Unity version 3.1(2b) and earlier.
To update wave gain settings in the registry for Cisco Unity version 3.1(2b) and earlier
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Automatic Gain Control
Cisco Unity Automatic Gain Control and Registry Settings
Cisco Unity automatic gain control (AGC) gives subscribers consistent message playback levels through the normalization of recordings. AGC affects recordings only. It is on by default, is controlled by registry settings, and is applied to voice samples after they have passed through all external hardware.
AGC does not improve the quality of recordings; it only addresses volume issues. For example, it cannot improve garbled incoming messages.
Because automatic gain control is enabled by default in Cisco Unity version 3.1(2c) and later, systems upgraded to 3.1(2c) and later may experience a problem where the existing greeting and name recordings sound louder than new greetings and names recorded after the upgrade. To prevent or resolve this problem after an upgrade, use the Set Volume utility to match the existing greeting and name recordings to the gain levels of Cisco Unity after the upgrade.The default values for the registry settings should be used for all Cisco Unity version 3.1(2c) and later upgrades. If you have not already done so, do the procedures in the "Set Volume Level Utility" section.
If you are using Dialogic voice cards, Cisco Unity AGC should be turned on, and the recommended settings for AGC in Table 6-4 are applicable.
The following registry keys determine how Cisco Unity AGC normalizes recordings.
To disable Cisco Unity AGC
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Dialogic Voice Card Automatic Gain Control and Registry Settings
Dialogic voice cards adjust the volume of recorded messages by using their own on-board AGC. Adjusting the playback volume for all recordings on systems equipped with Dialogic voice cards is done by changing the Median Volume registry setting. This setting is also used in the case of a dual integration, when you want to change the output volume level on the PBX side without affecting the Cisco CallManager side.
Cisco Unity AGC should also be enabled on systems with Dialogic voice cards.
To adjust the playback volume of recordings for Cisco Unity systems equipped with Dialogic voice cards
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The default setting for analog voice cards is 50, and the accepted range is between 0 and 100. Note that this setting is not in decibels, and that the numerical values are not linear. For example, a setting of 100 is louder, but not twice as loud as 50. Make a small adjustment to this setting of no more than 10 units louder or quieter.
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The default setting for analog voice cards is 50, and the accepted range is between 0 and 100. Like the Median Volume key, this setting is not in decibels, and the adjustments are not linear. Make a small adjustment to this setting of no more than 10 units louder or quieter.
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Comfort Noise
Comfort noise is low-level background noise generated on a IP device. Its purpose is to simulate the hiss produced in a circuit-switched connection, and it can be generated when there is no audio from Cisco Unity, for example, during a transfer or between system prompts.
Comfort noise is not sent over the network, and is audible only on the IP device that receives a comfort noise generation packet. Comfort noise generation packets are sent by Cisco Unity when it is integrated with Cisco CallManager, and when the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\
Avaudio\Parameters\ComfortNoise registry setting is enabled.The Cisco Unity ComfortNoise registry setting controls the ability of Cisco Unity to send comfort noise generation packets to an IP phone, or to a gateway that is enabled to receive and respond to comfort noise generation packets. This registry setting does not affect comfort noise generation on a call between two IP phones. Cisco Unity also does not respond to comfort noise generation packets sent by other devices. These packets are treated as silence at the wave driver level.
If subscribers hear an audible hissing noise when there is no audio from Cisco Unity, and if it is judged to be too loud a noise, confirm that the Cisco Unity comfort noise registry setting is enabled (set to a value other than zero), and then adjust the setting to a lower value as needed. The default value set during the Cisco Unity-CM TSP install is -50dB.
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There will always be some amount of hissing noise between prompts. The Cisco Unity ComfortNoise registry setting only tells the IP phone or gateway how loud that hiss should be. A value of zero causes the IP phone or gateway to use its default hiss level.
To view and adjust the Cisco Unity comfort noise registry setting
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