Background

There are different scenarios in which calls are made using speakerphones. For example:

• In manufacturing floor where the employees want to have an open communication channel without the limitation of headset or handset.
• When using intercom devices.
• When more than one person needs to listen to the call (e.g. in conference rooms).
• When making calls using the laptop’s built in microphone & speaker.
• When using special mobile devices – like mobile health safety monitoring.

Impact on Audio Quality

In all the above scenarios the usage of speakerphone causes the following audio quality problems:

• Acoustic Echo. Since the audio that is coming out of the speakerphone is captured by the microphone the result is that acoustic echo is generated.
• Howling. In some cases, especially when the audio signal is strong, howling will be generated. Such an effect usually causes the termination of the call by the participants.
• Ambient Noise. The microphone usually captures a lot of the ambient noise which reduces the overall quality of the call.
• Unstable volume level. Volume level might change during the call based on the changing distance between the speaker(s) and the microphone and the changes in the direction of the speaker’s mouth.

How to improve audio quality?

It is clear that in these scenarios you need to use a good audio filter for:

• AEC – Acoustic Echo Cancellation.
• NR – Noise reduction.
• AGC – Automatic Gain Control.

Unfortunately, we have seen many cases in which due to limited CPU power in the phone (especially in mobile devices) or bad implementation, the audio filters are simply not good enough to handle the loud echo & noise that are generated when using speakerphone. Therefore, in such cases, network solution should be used. Network solution is a software or hardware that is running in your VoIP network and filters the audio that is coming from the “noisy” devices.   SoliCall’s PBXMate is a plug-and-play network solution software that works with all standard VoIP networks.