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What Affects Voice Quality in VoIP Calls


Portrait of sitting at home working with computer and wearing headset
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Quality and reliability were the two darkest spots on VoIP's reputation for the past years. Now, in many cases, gone are the days when using VoIP was like testing walkie-talkies! There has been much improvement. But still, people are very finicky about voice quality in VoIP because they are used for years to the impeccable quality of landline phones. Here are the main things that affect voice quality in VoIP and what can be done to maximize quality.


Your Internet connection always tops the list of factors affecting voice quality in VoIP conversations. The bandwidth you have for VoIP is the key for voice quality. For instance, if you have dial-up connection, don’t expect great quality. A broadband connection will work right, as long as it is not spotty, and not shared with too many other communication applications. Bandwidth dependency is besides one of the main drawbacks of VoIP.


The VoIP hardware equipment you use can greatly impact on your quality. Poor quality equipment are normally the cheapest ones (but not always!). It is therefore always good to have as much information as possible on an ATA, router or IP phone before investing on it and starting to use it. Read reviews and discuss about it in forums. It might also be that the hardware you choose is the best in the world, but still you get problems - because you are not using hardware that suits your needs.

For an ATA/Router, you need to think of the following:

  • Compression technologies (codecs) supported
  • Echo cancellation, which is a mechanism for decreasing echo
  • Firewall and security support

Phone frequencies
The frequency of your IP phone may cause interference with other VoIP equipment. There are many cases where people using 5.8 GHz phones have been getting voice quality problems. When all troubleshooting tricks failed, changing the phone to one with a lower frequency (e.g. 2.4 GHz) solved the problem.

Weather Conditions

At times, the voice is terribly distorted by something called static, which is a small 'dirty-weed' static electricity generated on broadband lines due to thunderstorms, heavy rain, strong gusts, electrical impulses etc. This static is not very much noticeable when you surf the net or download files, which is why we don’t complain about it when we use the Internet for data despite it be here; but when you are listening to voice, it becomes disturbing. It is easy to get rid of static: unplug your hardware (ATA, router or phone) and plug it back again. The static will be brought to naught.

The effect of weather conditions on your connection is not something you can change. You can have some short-term relief in some cases, but most of the time, it is up to your service provider to do something. At times, changing the cables solves the problem completely, but this can be costly.

Location of your hardware

Interference is a poison for voice quality during voice communication. Often, VoIP equipment interfere with each other thus producing noise and other problems. For example, if your ATA is too close to your broadband router, you might experience voice quality problems. This is caused by electrical feedback. Try moving them away from each other to get rid of the garbled calls, echoes, dropped calls etc.

Compression: the codec used

VoIP transmits voice data packets in a compressed form, so that the load to be transmitted is lighter. The compression software used for this are called codec’s. Some codecs are good while others are less good. Put simply, each codec is designed for a specific use. If a codec is used for a communication need other than that for which it is meant, quality will suffer. Read more on codecs here.

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