Gone are the days when Nokia would pack in a really loud speaker into a smartphone and call it a “music phone”. Lately, audio and music playback in smartphones has improved significantly. This has everything to do with the powerful new hardware chips that handle audio playback and the improved algorithms, that process sound better than ever before.
In a smartphone, the audio is processed by digital-to-analogue (DAC) converter hardware. So it’s important to understand the difference between analogue and digital audio. The music we have heard over the years, on vinyl records or cassettes, came from an analogue source. CDs and MP3 marked a shift to digital formats. In the latter, your digital music is saved as 0s and 1s, just like any digital data. DAC hardware understands those 0s and 1s and converts them back into the melodies they are supposed to be.
However, not every phone has the same DAC hardware. That is why the sound may vary even if you’re using the same app, music file, earphones or speakers. Some phones have a dedicated DAC chip, while others rely on the chip integrated with the rest of the processing hardware. If you are looking for a smartphone with great audio, look for one with a dedicated DAC chip.
Some examples of dedicated DAC hardware include the ES9218 Quad DAC in the LG V20, which has a built-in headphone amplifier to negate the audio-detailing loss during transmission. Similarly, the Samsung Galaxy Note 5 has the Wolfson DAC.
However, two phones with the same audio chip don’t always have the same level of audio output either. How well a phone maker optimizes the audio chip’s software algorithm plays an important role.
While some phones use the audio codecs that come by default with the processing hardware, phones that are positioned for music lovers tend to use the overlay of better-tuned codecs. For example, phones based on the Qualcomm Snapdragon 820, such as Xiaomi Mi5 and HTC 10, take advantage of the Qualcomm Aqstic audio codec that supports up to 192-kHz/24-bit playback. The Qualcomm codec also comes with an Aqstic smart PA (power amplifier), which boosts the audio output in the phone’s speakers.
Codecs are designed to decode the data across different file formats and, over the years, the focus has been on keeping file sizes as small as possible without sacrificing quality.
Hi-res audio is a popular term for higher-quality audio formats, and codecs such as ALAC (Apple Lossless Audio Codec), DSD (Direct Digital Stream) and MQA (Master Quality Authenticated) are available on smartphones. They offer better audio quality but at the cost of larger file size since it wouldn’t be compressed as much. Marshall London and LeEco Le Max 2 support these audio formats.
How headphones CAN help
While your smartphone may be able to deliver the best audio quality, it will be of little use if you don’t have good headphones or earphones. Manufacturers have now begun using surround-sound technology in smartphones. Dolby Atmos, for instance, uses head-related transfer functions (HRTF) to process binaural sound emanating from a particular point. For example, if a user is watching an action movie or a game with lots of gunshots, smartphones powered by Dolby Atmos will be better equipped to tell which side of the screen a gunshot was fired from. The Dolby Atmos feature has been used by phone makers such as Lenovo, HTC and LG.
LeEco’s CDLA (Continual Digital Lossless Audio) technology works with unique headphones that the company ships with its phones. In a traditional 3.5mm jack-based set-up, the decoder is located in a smartphone and the headphone itself just delivers sound. LeEco has moved the audio-processing chip to the headphone. This reduces audio-detailing loss and enables a more wholesome listening experience. Incidentally, LeEco was the first phone maker to do this; Apple and Motorola, among others, have followed.
How to buy
The notion that speakers placed on the front (as seen in Nexus 6P and Moto phones) deliver better surround sound than those placed on the back panel, is not always true. Some of the best smartphone speakers can be found in the Apple iPhone 7, in which the speaker is placed at the base. The only advantage of front-facing speakers is that they ensure the sound doesn’t get blocked if a user is holding the smartphone.
Wireless headphones are growing in popularity, especially for use with smartphones. The absence of wires does add an element of convenience. But with most kinds of Bluetooth implementation, there will be some loss of quality in wireless streaming, compared to wired audio playback. If you don’t really need the convenience of wireless, wired is still a better bet.
Best phones for music lovers
£399, or around Rs34,000 (shipping extra); Marshallheadphones.com
British audio brand Marshall is well known for premium speakers and headphones. Their Android phone, called London, has nifty design elements such as a one-click music access button and a scroll wheel for volume control. It packs in Cirrus Logic WM8281 signal-processing codecs, and bundles high-quality earphones.
Apple iPhone 7/iPhone 7 Plus
Rs60,000 onwards; Apple.com/in
Shifting the analogue headphone jack to the digital Lightning port for audio has just added to the Apple iPhone’s audio-playback capabilities. With Lightning-capable headphones from the likes of JBL and Philips, among others, the integration of DAC in the headphones themselves is the reason for the superior sound.
Leeco Le Max 2
The second edition of the Le Max smartphone offers one of the best audio outputs in headphones. The high-quality audio is available only with the proprietary CDLA headphones bundled with the smartphone.
Asus Zenfone 3 Ultra
The Asus ZenFone 3 Ultra uses integrated DACs to offer 192-kHz/24-bit audio playback. To deliver high-quality audio in headphones, it uses hi-res audio (HRA) technology and DTS Headphone X 7.1 surround-sound technology. It uses a five-magnet speaker which provides greater bass extension using Asus’ smart-amplifier technology.
Sony Xperia XZ
The Xperia XZ does not have a separate DAC, relying instead on smart codecs to ensure high-res audio compatibility with the Digital Sound Enhancement Engine (DSEE HX) and Clear Audio+ features. Plug in high-quality headphones, and the difference becomes clear.
LG’s new flagship smartphone uses a dedicated ES9218 Quad DAC chip to deliver high-quality audio. It keeps SNR (signal-to-noise ratio) levels lower and allows users to optimize the sound quality in connected headphones and speakers in the phone’s settings >sound>HiFi Quad DAC. You can experience the sound difference in both earphones and speakers.
Equipped with Qualcomm’s Aqstic Codec and 24-bit DAC, the HTC 10 provides high-quality audio from both headphones and speakers. The phone’s own speaker is powered by HTC BoomSound HiFi technology that has a separate tweeter and subwoofer. HTC offers hi-res audio certified headphones with the phone.
Samsung Galaxy S7
The Samsung Galaxy S7 smartphone running on the Exynos Processor relies on Cirrus Logic’s CS47L91 audio codec to boost the audio quality in headphones and speakers. The CS47L91 codec uses its integrated DAC mechanism to deliver 24-bit/192-kHz audio—a treat for music buffs.