In an age where a smartphone can facilitate multiple services like video streaming, texting, social media platforms and unprecedented intelligent technologies. We tend to ignore a basic purpose that the devices were supposed to serve: a seamless calling experience. The audio quality of calls is not the most sought after feature in a phone. However, it is noticed when the quality does not meet the basic standards.
The handset’s hardware affects the audio quality of calls on Smartphones
The phone’s hardware is a major factor in determining the audio clarity. Most smartphones include high-quality microphones and speakers to provide their customers with a good calling experience. The speaker used for call transmission is often covered and protected with durable material to avoid damage. Hence, surrounding noise levels affect the quality of calls. Phones made by the Japanese manufacturer, Kyocera use special tissue-conduction vibration screens to improve call quality in noisy environments. The hardware also accounts for the efficiency of the sampling and reconstruction algorithms.
In addition to the earpiece, the radio and antenna design also contribute to the sound quality. The ability of the antenna to filter out the noise and connect to the carrier network highly determines the call quality. Keeping the antenna obstruction-free is hence, vital. Moreover, the placement of the antenna in the handset also adds to the end result. Several phones provide a better experience when handled on the left that on the right. This might solely be due to the obstruction caused by the right-hand and right-ear combination. Since most smartphones use planar and fractal antennae, the dimensions and position play a pivotal role.
The design of the transceiver to differentiate between several signals like Bluetooth, Wi-Fi, VoIP signals and VoLTE signals also contributes to the audio quality of the phone calls. Besides the shrinking earpieces and antennae that are being used, the small microphone placed to accommodate for the elegant design of the phone compromises on the voice quality transmitted to the other end of the line. While the hardware plays an important role in determining the audio quality of the calls, the back-end algorithms cannot be ignored.
Other factors affecting the sound quality of calls
Noise-cancelling algorithms form a major part of mobile communication. While most of them do a good job at filtering out background sounds, they are not an instant fix. These algorithms require some time to recognise and differentiate between the various background signals. As a result, they can eliminate consistent sounds like the vehicle horns or blowing wind, but cannot provide immunity against sudden disruptions like a crying baby. Moreover, voice echoes are tough to weed out using these algorithms.
Noise suppression cannot be performed at the cost of the natural acoustic variation in human voice, lest they should sound like robotic speech sounds. Even if your handset filters out a crisp human voice signal at your end, the next obstruction is faced while transmission. Most mobile phones digitise audio frequencies in the range of 300 to 3,400 Hertz. Due to the limited wireless spectrum, further compression is done to accommodate all coincident calls. This thus causes loss of information and audio-energy leading to broken words and voices at the receiving end.
A lot is also decided by the reconstruction algorithms at the receiver-end. While a standard landline phone can decode the signals without any loss, a cell phone loses out on more information while reconstructing the signal.
How can the call audio quality of your phone be improved?
Few upcoming technologies can dampen the damage caused to the call audio quality of your smartphone. One of the most popular ones is HD Voice. While increasing the range of audio frequencies to 50 to 7,000 Hz, the transmission standard collects and relays more diverse speech signals.
VoLTE (Voice over Long-term-evolution) is another technology that can offer you with a quick-fix. It treats voice-signals like regular data traffic and compresses it into standardised packets that can be relayed over an IP backbone. This eliminates the need to convert the data into different formats, thus causing negligible loss. However, many carriers do not facilitate VoLTE yet.
Since the quality of VoIP services like Google Hangouts, Skype etc. have improved over the years. One can use them for a more promising call-experience. With OEMs investing on better hardware for their respective phones. One can also expect better designs and performances from the devices. The advent of technologies like 5G connectivity has caused the market players to up their game in mobile communication.