The Beginner’s Guide to Voice Quality Testing


We’ve all experienced an interaction with a business's interactive voice response (IVR) system where poor voice quality makes it almost impossible to complete an automated task or get “self-help” when you need it. Listening to broken prompts, hearing jitter or noise on the line, along with any other audio quality issue makes it hard to understand the navigation options. Poor voice quality can lead to misunderstandings, stress and, sometimes, the complete abandonment of calls.

Having poor voice quality affecting your personal calls is frustrating for all involved, but having degraded audio quality can be damaging to a business. So how do you know when voice quality is potentially impacting your organization’s phone numbers experience? For a global business, customer call experiences can vary based on their location and the respective contact number they rang. To accurately assess callers' experiences, you must test your network's voice call quality.

So, what exactly is voice quality testing?


How Do You Conduct a Test?

Voice quality testing could be as simple as asking someone to make a call to one of your contact numbers, and rate various aspects of the call quality. Contact centers, conferencing services, and phone number providers frequently employ this method. They often seek assistance from employees, friends, and family around the world. Sometimes, they even hire freelancers for these calls.

But this method isn’t scientific and unfortunately it’s frequently unreliable. A person's voice quality experience is subjective. They can't provide an accurate measurement of all characteristics. Additionally, those individuals won’t always be available to conduct test calls when needed. Relying on this labor-intensive process to test voice call quality, particularly across a multitude of global contact numbers, could be highly costly and potentially unmanageable.

A more scientific and reliable method of testing voice call quality is to use a pre-recorded voice sample. This test compares the audio output (at the listener’s end), to the original voice file (played on the ‘talker’ side), to create unbiased and objective metrics of the true audio quality that the listener experiences. 

Here's a brief outline of how Cyara conducts a voice call quality test:

  • Using a predefined test script, Cyara uses the carrier network to dial your toll-free or other inward dialing number.
  • The test script navigates your IVR call flow just as a customer would.
  • Your IVR plays back the pre-recorded WAV files to the script just as it would to an actual caller.
  • The system analyzes the WAV file playback to produce a dependable audio quality score.


By originating test calls within the same global region as your normal call patterns, voice quality testing in this manner uncovers the genuine experiences of callers worldwide. It also provides full control for conducting these tests at any time, whether it's day or night.


What Can Voice Quality Testing Tell you?

Using this type of voice quality testing, the call recording will be analyzed and compared with the original voice sample through an established, objective voice quality measure known as Perceptual Evaluation of Speech Quality (PESQ). PESQ is an International Telecommunication Union (ITU) standard for measuring audio quality and takes into consideration a wide array of characteristics such as:

  • Audio sharpness
  • Call volume
  • Background noise
  • Variable latency
  • Audio lag
  • Clipping
  • Audio interference


This enables you to test call quality effortlessly across all call types, including mobile, fixed-line, toll, toll-free, VoIP, and PSTN, using an agreed and internationally recognized standard.

Through ongoing voice quality testing, you will have the data you need to guarantee your customers are experiencing high audio quality at all times. You’ll also better understand how, when and why this varies, especially when calling from different locations.


How Can Testing Voice Call Quality Help Your Business?

We’ve discussed how voice call quality testing works, but what should you do with this information?

1. Help your engineers to get ahead of voice quality issues 

Proactive voice quality testing allows you to receive alerts at the earliest possible moment regarding potential issues. While your engineering team may be monitoring the performance of your internal network, they have no control and, often, no visibility of what’s happening on the external network. As such, poor voice quality issues are often unknown unless a customer chooses to make a complaint. This means that the fault can be ‘live’ for a significant period before it’s identified. And that your customers are being negatively affected.

Continuous proactive voice quality testing is necessary to ensure you receive alerts as soon as issues occur. The test results will also provide you with the intelligence you need to promptly fix the problem. Cyara’s voice quality testing, for example, comes with full call detail records (CDRs) that allow you to quickly pinpoint issues, and call recordings allowing you to listen to instances of poor quality. Leveraging the call detail information, you can then troubleshoot more quickly and reduce your mean time to resolution (MTTR). 

2. Protect your brand and your reputation

The ultimate aim of having proactive monitoring, paired with alerts for voice quality monitoring is to protect your brand. Any degradation in voice quality will lead to a reduction in your customer’s experience, which, in turn, will cause damage to your brand’s reputation. By promptly identifying voice quality issues and having the necessary insights for quick adjustments to your contact center platform, you can proactively manage your interactive customer journeys, safeguarding your reputation.

 3. Test the standard of voice call quality being provided by your carriers

Businesses typically rely on their carriers to provide them with an agreed level of service. And, telecom companies often rely on their own partners to ensure their voice calls correctly move along the full call path. In the case of an international call, that path may have a variety of potential routes that it could follow, with hops and handovers made to various carrier partners along the way.

Yet, despite agreed contracts and service level agreements (SLAs), businesses are often unaware of the true performance that their carriers are providing them with. Likewise, carriers are frequently blind to the performance of their partners’. For example, some may be transcoding (compressing the audio files) at busy times to save on data. Even if calls are not being dropped completely, this transcoding is likely to result in a loss of voice quality. And, because this may be happening spontaneously, it can be difficult to spot without an ongoing testing and monitoring tool.



Voice quality testing is essential for ensuring that your contact center and IVR deliver a smooth and satisfying customer experience. By testing your voice quality proactively, you can quickly detect and resolve any issues that may affect your call quality, such as network congestion, packet loss, jitter, or latency. You can also test different call flows and routes across your network, and compare the performance of your applications and providers. This way, you can make better decisions on which providers and routes to use for your voice calls. Moreover, you can verify that your carrier meets your SLAs and that your calls are not transcoded by any intermediate devices. Voice quality testing can help you improve your customer service, reduce costs, and increase brand loyalty.