Audio quality is essential, especially today, as we almost always communicate remotely, let’s see how excellent audio quality is obtained for IP phones. Audio quality is fundamental; today, we communicate more and more at a distance and understanding what we say is primarily linked to audio. But that’s not just what we say; excellent audio quality is the only thing that allows us to understand how we say it, the intonation, the irony, that infinite range of shades that can radically change the meaning of a sentence.
Oral language has a unique strength: it conveys the sense of what is stated more transparently: a short pause before a word or a slightly different emphasis is enough to change the meaning of a statement completely. It is essential to transmit the tone to the phone exactly as it is, avoiding delays and distortions, just as if the interlocutors were sitting in the same room. But how is this achieved? Speech is converted from analog to digital and vice versa, and the transmitted audio is compressed, packaged, and unpacked. Yet something is created that can be recognized as an individual “voice”—a little magic. Snom gives us a peek behind the scenes to understand the elements of good audio quality in IP telephony.
Disturbing Factors Of Audio Quality
In digital communication, speech is digitized via codecs and compressed into data packets. But the path taken by the data packets (routing) is also essential. It is, in fact, necessary that all data packets arrive in the correct order and at the right time. If this does not happen, a distortion occurs, that is, a variation in the execution time of the data packets, perceivable as the “broken” or “metallic” voice, particularly evident “free” telephony platforms are used, such as Skype and like, where no distinction is made between voice files and other formats. In this case, the voice files have no prioritization, which is why they often reach the recipient incorrectly or late.
Another problem occurs when the selected Internet connectivity does not have sufficient bandwidth: depending on the codec used on an excellent voice transmission, each telephone connection needs between 3 Kbit / s – GSM – and 128 Kbit / s – G711-G722 -. The prioritization of voice traffic initially slows down the network, which can be avoided using a codec with minimal bandwidth consumption, which can cause quality losses.
Audio Quality Is No Accident
Overcoming these hurdles, however, is still no guarantee of sound voice transmission, as the subsequent potential weakness comes into play here: the chassis! The problem can arise already during the initial design of the terminals and in evaluating the optimal positioning of speakers and microphones according to their application areas, for example, in the handset or the speakerphone housing. Once the ideal conditions have been created, the next step is selecting the hardware components to be used. In this context, compatibility between members is also essential to ensure that all parts work together optimally and that you have sufficient capacity to encode and send data in real time.
In the case of terminals Snom, the audio quality assessment process begins as soon as the first industrial prototype is available. This process then proceeds and is constantly optimized for the product’s entire life cycle. Over the years, the Berlin manufacturer, thanks to its experience and audio laboratory, has continuously improved the audio quality of its products by combining the latest DSP algorithms with VoIP transmission. In particular, Snom solved several problems of VoIP technology, such as processing and network delays, packet loss, and noise. An aspect that the company boasts among its flagships.
This attention to detail during the design phase makes all the difference in the quality of voice transmission in phones. At this juncture, subjective tests are as necessary as objective ones: a theoretically well-tuned phone can still present poor audio quality in practice. Well-calibrated devices are those in which a phase of subjective tests follows a cycle of objective tests. Both evaluations meet expectations about the acoustics of the handset and the speakerphone. The quality of the audio is taken for granted by most users. How complex and laborious this technology is today becomes apparent only when confronted with the often poor audio experiences of the most sophisticated smartphones or designer desktop devices.