What Causes Poor Sound Quality?
Poor or scratchy sound is a symptom of a problem with your network connection, or network card. The following issues could contribute to poor sound quality:
There may be packet loss on the IP network. Check the network performance, latency, and throughput. A 200 millisecond round trip latency as determined from a ping (see -It doesn't work- above) should deliver good quality audio.
To test this use the Voipfone sound test by dialling 152.
Network devices may have performance problems. Make sure you are using the latest driver.
Jittery or Stuttering Audio
Jittery or stuttering audio during phones calls is most likely due to a bandwidth or data packet loss problem with your Internet Service Provider or your Local Area Network.
If you find that the problem only occurs when you or someone else on your network, start downloading or uploading from/to the internet you may need to increase your bandwidth.
Alternatively, some modern routers have a function called Quality of Service (QoS) which gives priority to voice traffic. Consult your manual.
Audio Contains Pops in the Voice
Popping sound is a symptom of over-modulation. Ask the other party to decrease the microphone slider and/or adjust the microphone gain.
Audio Contains Background Noise
Significant background noise can be due to the level of the silence threshold. Have the other party adjust their silence threshold. They can do so by running the Audio Tuning Wizard.
Audio Contains an Echo
Try using a headset with your sound card. You will hear echo if your microphone can pick up your speaker sounds, such as when not using a headset.
Use a USB-enabled headset, which bypasses system sounds as it acts as its own sound device.
Are you using a boom type headset? Some boom headsets that sit on the ear can create feedback between the boom microphone and the headset.
The microphone balance is not muted in the playback section of Windows audio controls. When you are configuring sound, you may need to examine the volume control setting.
Microphone level may be too high or amplifier is turned on in the generic Windows audio controls.
Echoes on the Line
Echoes are caused at the opposite end of the call from the person who hears them.
They should not occur if the call is end to end digital (ie all VoIP) when using good quality, digital telephones.
Most echoes are caused by poor headsets with softphones or with digital phones with poor quality headsets or when using loudspeakers and microphones.
We find the most usual cause is when the person you are calling is using a softphone with loudspeakers and a microphone because your voice is then broadcast. His microphone then picks your voice up and sends it back to you.
The solution is a good quality headset at his end. But first, ask him to turn the volume down on his speakers as this can sometimes solve the problem immediately, or at least reduce it to a bearable level.
We have a technology called echo cancellation which can eliminate the problem. If the other methods have not worked for you this is how you do it:
Have the softphone open and press F8
In 'menu' go to advanced settings, silence settings and set:
Transmit silence to NO
Microphone silence detection to 75
Speaker Silence Detection to 75
Keep transmitting after silence to 750
You will find a sound test to help you diagnose your problem by dialling 152.
One Way Audio
Most one way sound problems are caused by firewalls restricting incoming connections.
See softphone problems above. For hardware phones the firewall issues are always found in the router; you will need to open ports 5004 to 5060 on your router to enable you to connect to our servers and register your phone on our network. See 'My phone shows 'discovering firewall' below.
Some IP telephones do not obey -Reverse UDP Mapping Rules-, which can cause one-way audio in your conversation. Try your call with this setting:
Menu -> Advanced System Settings -> RTP Settings -> Obey Reverse UDP Mapping Rules: No
1. For SIP Telephones and Adapters
If you are using a new SIP phone or ATA adapter and your caller can't hear you or you can't hear them, it is normally because you are using some type of firewall that requires manual configuration.
You will need to open ports 5004 to 5060 on your router to enable you to connect to our servers and register your phone on our network. See 'My phone shows 'discovering firewall' below.
2. For Softphones
Sound problems with softphones are usually caused by incorrectly set up sound card or microphone and headsets. Check that the microphone and earphone cables are in the correct sockets of the sound card and that volume controls are correctly set.
Some microphones need an extra 20db setting to be made on the sound card software (usually found under advanced settings) to work properly.
