How to evaluate an echo cancellation algorithm?

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On November 21, 2017
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Acoustic Echo Cancellation, echo cancellation

When you encounter an echo problem in your application, network or devices it is obvious you need to introduce an echo canceller. Your next step is to explore at least two possible locations for performing the echo cancellation: cancelling the echo on the client side or doing it on the server side. The decision […]

Noise map for call centers

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On September 4, 2017
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call center noise cancellation, call center noise reduction, noise map

Background Call centers suffers from significant ambient noise that is originated from multiple locations like: Other agents talking in the background. The supervisor/team-leaders shouting to instruct or enthuse the agents. A nearby gathering in the coffee corner. Such noise reduces the quality of the calls and directly impacts customer satisfaction. In addition the existence of […]

Echo Cancellation with negative echo tail

Posted by admin
On May 7, 2017
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Acoustic Echo Cancellation, echo tail

Background Echo path/tail is one of the most fundamental parameters when performing echo cancellation. In previous posts, we elaborated on the importance of echo tail and we also provided a Do It Yourself (DIY) method to calculate the echo tail. In most usage scenarios, the value of the echo tail will be a positive one […]

Noise reduction algorithms – PNR vs. RNR

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On January 3, 2017
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Noise Cancellation, noise reduction software

Background Recently SoliCall introduced the reference-based noise reduction (RNR). This new technology was added to our noise reduction portfolio which already contained profile-based noise reduction (PNR) and standard noise reduction. Following the RNR introduction, we got requests to elaborate on the difference between PNR and RNR as they both use a profile/learning mechanism. In this […]

Analyze the echo path yourself

Posted by admin
On September 4, 2016
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echo path, echo tail

Background The echo path is one of the most critical component during echo cancellation. You might have already heard this term or any of its synonyms (e.g. “echo tail”). When discussing the echo path we usually talk about two different aspects: a. The stability of the echo path. How volatile is this parameter ? Is […]

Time manipulation and its impact on echo cancellation

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On July 1, 2016
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echo cancellation, time manipulation, WSOLA

Background Time manipulation is a known technique in audio processing. It can be used to either compress the audio (resulting in speed-up) or expand the audio (resulting in slow-down). Usually this is done without altering the pitch and therefore without changing the fundamental signature of the voice.

Echo cancellation is now available for PJSIP

Posted by admin
On May 15, 2016
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Acoustic Echo Cancellation, PJSIP

Background PJSIP is an is a free and open source multimedia communication library. One of the most important components that influence the audio quality in VoIP communication solutions is the existence of a good echo cancellation. SoliCall’s acoustic echo cancellation software is a powerful echo cancellation technology that is also flexible to support and tune […]

Isolating the audio in VoIP networks

Posted by admin
On March 2, 2016
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Firewall, RTP, SIP, VoIP

Background In this post we would like to share with you a rare phenomenon we have seen in few sites that once it appears, it can cause a head ache to the network administrator. As opposed to the old telephony networks that was based on dedicated physical cables per call, usually twisted pair, the cables […]

How can echo suppression badly impact call quality ?

Posted by admin
On January 1, 2016
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echo suppression

Background Can phones/soft-phones with built-in echo suppression badly impact the audio quality? Surprising as it may sound the answer is positive. In other words, when a call center, or any other organization, purchase phones with built-in echo suppression it is jeopardizing the overall call quality. In order to analyze the reason for this phenomena we […]

Echo in Public Address systems – additional considerations

Posted by admin
On October 14, 2015
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Acoustic Echo Cancellation, AEC, public addressing

Background This post is a continuation to our previous post on AEC and Public Address systems. This post elaborates on additional considerations that should be reviewed when implementing and tuning acoustic echo cancellation software in PA systems. After analyzing relevant case studies, out of many important considerations, we have selected the below ones.

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