Active noise cancellation technology enables you to shield yourself from the ambient noise. Active noise cancellation headphones are using this technology and enable isolation from any noise in your background. As a result, you are not destructed by the background noise and you can focus on whatever you want to do: listen to music, enjoy a TV show or just taking a peaceful nap.

Can you use active noise cancellation headphones to improve the quality of phone calls? In order to answer this question, let’s drill down to the technology of the active noise cancellation headphones.

Active noise cancellation headphones – technology overview

Active Noise cancellation headphones are equipped with dedicated sensors that are located near your ears. These sensors pick up the ambient noise “a minute” before it reaches your ears. The processor in the headphone immediately generate an audio signal that is opposite from the ambient noise and plays it to your ears.  As a result, the ambient noise is cancelled before it reaches your ears.
Note that if you want to listen to music and you will play it on the loudspeakers;  you will not be able to hear it since the headphones will cancel it like any other ambient noise. Therefore, you have to play the music via your headphones so it will not be picked by the dedicated sensors.

What happens during a phone call?

Whenever you make a call using active noise cancellation headsets, you will not hear your ambient noise but since the active noise cancellation headsets do not shield the microphone; your party will hear your ambient noise. This might result in very strange scenarios in which you are not aware of your ambient noise while your party can clearly hear it. Your party might even consider this rude.

Therefore, we recommend you should either stop using active noise cancellation headphones during phone calls or make sure you also reduce the ambient noise captured by your microphone. SoliCall offers several noise reduction software products like SoliCall Pro that are suitable for this purpose.

The Elastix users enjoy from a powerful unified communication system with very professional graphical user interface that provides a friendly way for monitoring and control the system. The powerful system together with the the ease-of-use is one of the main reasons that attract customers into using Elastix. Up until recently, integrating the PBXMate, for audio quality improvement, with Elastix required a simply manual configuration. This turned out to be a drawback for users that want to enjoy a seamless and automatic integration between all components in their system.

PBXMate as an Addon to Elastix

The Elastix Addon platform enables certified products to be easily added to the Elastix system. Therefore, to enable the PBXMate users to enjoy from seamless integration with Elastix, a special version of the PBXMate was prepared that fully complies with the Elastix Addons platform. Few weeks ago, the PBXMate was formally certified and added to the Elastix Addons on-line repository.

Ease of use

Elastix users can now easily install the PBXMate Addon and it will run along-side the Elastix Server. In addition, The PBXMate graphical user interface is now accessible  directly from the Elastix graphical user interface under its PBX tab.

The PBXMate tab contains four sub-menus:

• README – initial instructions.
• Control GUI – Control Panel, Basic Setup & Licensing.
• Statistics – Real-time statistics of the calls together with quality indicators like jitter, packet loss, noise level, gain level and MOS score.
• User Manual – detailed user manual.

The hosted VoIP service is gaining popularity like other cloud-based infrastructure services. SMBs prefer hosted VoIP solution to cut down costs and operational overhead. In addition many providers offer attractive build-in features on top of the standard service.  As opposed to other IT services, VoIP is more delicate and if not handled correctly it will cause degradation in audio quality. From time to time we are being contacted by companies that are using hosted VoIP services and suffer from poor audio quality. Usually they complain about issues of echo & noise.

Echo

Echo is one of the most disturbing artifacts in telephony. Once it appears during a call, it is so annoying that is unlikely that the call could last much longer. There are many reasons for the appearance of echo but one of the factors that amplify the echo is the long delay. For more details, read the following post on echo in VoIP . Cloud based solutions are usually increasing the delay and therefore increasing the likelihood of suffering from echo.

Noise (both static noise and ambient noise)

The problem of noise is usually due to the equipment that is being used. Sometimes the phones or ATAs generate a static noise and/or does not cancel the ambient noise.  The problem can even be caused by the network equipment on the cloud. In addition absence of network noise cancellation might contribute to this disturbing phenomenon.

How to improve Audio Quality

SoliCall specializes in software products that improve audio quality in many environments including Hosted VoIP. SoliCall can help you reduce the above mentioned problems and enjoy high quality calls without replacing your vendor or equipment. For SMBs that have multiple phones, SoliCall offers the PBXMate that can be configured as a Sip Proxy and provide centralized audio filtering for all of your phones. If you only have one phone, you can use SoliCall’s Personal PBXMate that can be connected to a single phone and improve its audio quality.

Around the world, the competition for mobile operators intensifies every day. Their revenue shrinks due to increasing competition and the alternatives for free VoIP call on the data channel. In addition to the reduction in revenue, mobile operators are constantly required to invest a lot of money upgrading their infrastructure.  It is clear that eventually the reduction in revenue together with the increase in costs might bring disaster to the industry unless mobile operators will learn to increase and leverage their competitive edge.

What is the Competitive Edge for Mobile Operators?

Let’s go back to the basics. One of the biggest advantages that mobile operators can show is their ability to deliver high quality telephony. This is their core business and what their infrastructure was planned to deliver. Operators can make assure the calls will not suffer from any external interruptions. Their infrastructure is capable of providing robust calls regardless delays or load on the Internet. On top of this advantage, Mobile operators need to emphasize their audio quality and make sure it is always ahead of any other free alternative in the market. In this respect, there are several issues that should be addressed. Some of them (like moving from narrowband to wideband) might require a change in the infrastructure so we will not discuss them. Others are simpler to add to the existing infrastructure.

Quality Audio – Ambient Noise

As elaborated in our previous post, one of the biggest quality problems that mobile phones create is the ambient noise. Since mobile operators have full control over the streaming audio, they have simple ways for improving the quality of the audio and reducing the ambient noise.

Quality Audio –Personalization

Mobile operators should utilize the fact that mobile phones are personal devices. This information can be used to improve audio quality even further. For example, when a business person makes a business call using his personal mobile phone, only his voice should be transferred to the other side and all other voices, like kids in the back of the car, should be suppressed as their voice is different from the voice of the phone owner.

If we just got a penny every time we heard the sentence:  “Our telephone equipment provides a superb audio quality… it could not be better…”.  Unfortunately, although this sentence is commonly used, it is one of the biggest self-deception in the industry.

When your friend calls you from the Mall or from the road don’t you hear the noisy in the background?  How many times did you suffer from a terrible noise while in a conference call?  When you make a call with your bank do you hear the surrounding of the agent that is talking to you? And there are many other examples.  So, if an audio quality issue does exit, then why people keep saying that the audio quality is excellent?

Who is to blame?

During its long history mankind developed the tendency to accept reality AS-IS.  Accepting the current state is a critical enabler for running normal day-to-day life but it should never come on the expense of a continuous quest for improvements.  Two decades ago, the emerging market of mobile telephony introduced an existing new way for communication. Unfortunately the new way of communication also created a new reality – people talk from everywhere and therefore introduce a lot of ambient noise in telephony.  Hey, but this is reality isn’t it? If someone wants to have a quiet conversation then he/she should simply go to a quite location, right? Wrong. Today’s advanced technology enables us to improve the reality and aiming for noise-free calls regardless the location from which the calls are being placed.

What should we do?

Next time you make calls check for yourself if the calls are really clean or do they contain noises that you were persuaded to consider as inevitable?  Take this information into account whenever you select your audio provider. Keep in mind that as long as ambient noise exists there is room for improvement.

For network administrators and operators, SoliCall offers a free trial of its PBXMate software product. During the trial period, the quality of the calls will be accurately monitored, analyzed and improved.

In the beginning of this year, Adobe has released an acoustic echo cancellation as an integral part of its platform. Based on the feedback we are getting, the problem of echo was successfully reduced but not in all environments and especially not in environments that include mobile platforms.  SoliCall’s network echo cancellation technology could be used, in these cases to eliminate the echo. Following are few options of doing so.

SoliCall Pro

You can install the product SoliCall Pro and use its capability to cancel echo originated from both ends of the call. This solution is especially appealing in environments that resemble to call centers where calls are made between many customers to a limited number of representatives. All you need to do is to install SoliCall Pro on the computers of the representatives and let it cancel both near end and far-end echo. Depending on the delay in the calls, you might want to increase the aggressiveness of the echo cancellation. Running SoliCall Pro on the representative’s computers enables you to cancel echo that is originated from both ends of the call including echo originated from any mobile customer.

PBXMate

The PBXMate is a plug-and-play product for improving audio quality and cancel echo in VoIP networks that supports the SIP standard. Although SIP is the most common standard in VoIP, basic VoIP networks intended only for Flash clients usually do not have a built-in support for SIP. In such case, in order to use the PBXMate you need to add support for the SIP standard. One promising way of doing so is by using the new Adobe’s Flash Media Gateway (FMG).  Once you have SIP enabled, you can route all calls that require echo cancellation to the PBXMate SIP Trunk.  There is no coding involved in this solution and it is all a matter of configuromg the call flow.

Server SDK

SoliCall’s Server SDK is available as a software library which you need to integrate into the code of the server. This technique is most suitable for companies that have built their own server in which they have full access to the raw audio signal. In such case it is relatively easy to integrate SoliCall’s Server SDK as part of the server and audio path, feed it with a “noisy” audio signal and get back a “clean” audio signal.

Client SDK or Mobile SDK

In the event that you have access to the audio on the client side (including mobile devices) you can integrate SoliCall’s Client SDK or Mobile SDK into your software in order to cancel the echo.

One of the first steps SMBs take towards VoIP is to add ATA to their existing analog telephone network. There are many well known brands of ATAs in the market today like Linksys PAP2, Cisco PAP2T, Grandstream HandyTone and others. Regularly we are requested to improve audio quality in such telephony systems – especially to cancel echo, adjust volume level and remove noise.

Improving audio quality in analog telephony systems that use ATAs

Although in such cases the native telephony system is analog, the ATA gives it an interface to VoIP and therefore enables the analog telephony system to benefit from the many advantages that VoIP has to offer. One of these advantages is the ability to use SoliCall’s plug-and-play PBXMate software for VoIP that cancels echo, reduces noise and adjusts audio volume.

What is the PBXMate?

The PBXMate is a plug-and-play software product for VoIP networks. The PBXMate can be plugged between the ATA and the internet. After plugging the PBXMate, it improves and monitors audio quality for all incoming and outgoing calls. As a result, a significant boost is given to the audio quality of the existing analog telephony system.

Many times we are asked for ways to cancel noise and improve audio quality in existing telephony networks.  The majority of the requests come from call centers and SMBs that are looking for simple plug-and-play solutions to resolve audio quality issues that they are facing.  Since most of these request arise for companies that already invested a lot of time & effort in building and configuring their VoIP network, they are reluctant to consider solutions that will require them do to changes in their network.

Client-side solution vs. Server-side solution

You would expect that a solution that does not require any change in the network should be a client-side solution. For example, install expensive headsets in every IP Phone. But, apart from the heavy cost of client-side solutions and their limited capabilities, client-side solutions are hard to maintain and result in high TCO.

Fortunately, the technology today enables designing products that, on one hand, are centralized and have low TCO but, on the other hand, behave like client-side solutions that could be integrated without any change to the VoIP network.  Such a technology is called fully transparent SIP Proxy.

PBXMate – A fully transparent SIP-Proxy

The PBXMate is a centralized software product that can work as a fully transparent sip proxy.  As a result the PBXMate could be integrated in any VoIP network within minutes. After the smooth integration, the PBXMate will immediately improves the quality of the calls, reduce noise, cancel echo, control volume level and maintain overall high audio quality. The PBXMate is a mature product that is already being used world-wide by many organizations that have different network components & architectures.

Acoustic Echo Cancellation (AEC) is a method of removing the echo from the audio signal captured by the microphone. This is done by using the audio that is played to the speakers as a reference audio signal. Most AEC algorithms require that both audio signals, i.e. the signal captured from the microphone and the signal sent to the speakers, MUST be clock synchronized otherwise the AEC algorithm is unable to lock-on the echo path and perform echo cancellation.

When will the Acoustic Echo Cancellation fail?

Most AEC algorithms will fail if the signal captured form the microphone and the signal sent to the speakers are not 100% clock-synchronized.   This can happen in many cases like:

• When the sound card that is being used is a low-end one that does not have a built-in clock mechanism to synchronize the input and output audio signals.
• When the VoIP application is configured to use different sounds card for input and for output. For example, a USB web-cam is used as the capture device while the laptop’s built-in speakers are being used for playback.

Conclusion

If your VoIP application needs to cancel echo in any of the above conditions, you should not use a standard echo cancellation. In such case you need to use a robust echo cancellation that is capable of working in volatile environments.  SoliCall’s unique echo cancellation is a robust algorithm that is capable of working in such complex conditions.

One of the main problems in mobile devices is their limited CPU Power. As a result the delay in the audio signal is increased and from time to time portions of the audio signal might get lost. In order to resolve these problems, you need to verify that your VoIP application is optimized to your low-end CPU. For example, it should use fixed-point arithmetic instead of floating-point one, it should minimize the usage of dynamic memory allocations and completely avoid it after the initialization phase, for critical sections it should use native programming language like C/C++. In addition, your VoIP application should have enough flexibility to dynamically change its CPU consumption based on the overall load on the device. This flexibility could be achieved by changing bandwidth, CODEC, audio filtering settings, etc.

Noise Reduction

This is one of the biggest audio quality issues that was actually “invented” by mobile devices. In most cases you cannot release for production a VoIP application for mobile device without making sure the audio is filtered by a decent noise reduction algorithm.

Echo Cancellation

This feature is mandatory when you want to allow your users the freedom of using a speakerphone. What you should be looking for is an optimized AEC algorithm for mobile devices. Since the delay might increase due to CPU consumption, you need to make sure that your AEC algorithm can optimally handle long delays.

Standard Protocol

It is important to use a standard signaling protocol (usually SIP), to preserve the option of activating, in the network,  today or in the future, plug-and-play third party components to resolve quality issues that could not be resolved on the client side. For example:

• Clients with very limited CPU or very loaded that cannot run the local echo cancellation or noise reduction, should get “help” by audio filtering in the network.
• Improving the audio that is being heard by your customers – the mobile device owners – by reducing far-end noise & far-end echo. Your customers deserve to hear crystal clear in addition to being heard crystal clear.
• Centralized monitoring and alerting on quality problems.