How Software Upgrades Improve Audio Quality in Apple HomePod and Other Devices

The secret behind the excellent sound quality of the new Apple HomePod may be advancements in software. 

The HomePod looks like previously discontinued models of the smart speaker. Apple recently revived the HomePod, and early reviewers said it sounds even better than earlier versions. Experts say the improved sound is thanks to algorithms that use the power of computation to boost sound quality. 

"Computational audio plays a significant role in offering the best audio quality to users," Prakash Khanduri, an audio architect at Ambiq, told Lifewire in an email interview. "All mobile and wearable devices use computational audio to enhance the audio quality for these devices in adverse conditions such as high background noise. The devices use machine learning and conventional digital signal processing algorithms in dedicated processors to improve audio quality."

Better Sound Through Tech

Some tech reviewers have already heard music from the new HomePod, and their reactions have mostly been positive. According to Apple's press release, the secret sauce behind the great HomePod sound is "advanced computational audio for a groundbreaking listening experience, including support for immersive Spatial Audio tracks." 

The company also boasts that the HomePod "has a custom-engineered high-excursion woofer, powerful motor that drives the diaphragm a remarkable 20mm, built-in bass-EQ mic, and beamforming array of five tweeters around the base work together to achieve a powerful acoustic experience. The S7 chip is combined with software and system-sensing technology to offer even more advanced computational audio that maximizes the full potential of its acoustic system for a groundbreaking listening experience."

The HomePod uses advanced audio technology to provide high-quality sound, Roy Castleman, the CEO of Computers In The City, told Lifewire in an email interview. "One key feature is its use of an array of seven beamforming tweeters, which allows for precise control of the sound output and eliminates echoes and reverberation."

Castleman said the HomePod uses an S7 chip, which allows for real-time modeling of the room's acoustics and adjusts the audio output accordingly. The speaker also uses advanced software to automatically tune the audio output to match the music being played.

The HomePod recognizes sound reflections from nearby surfaces to determine if it is against a wall or freestanding and then adapts to sound in real-time. Precise directional control of its beamforming array of five tweeters separates and beams direct and ambient audio. 

The Power of Computation

Khanduri said computational audio uses various algorithms, including audio coding, speech recognition, echo canceling, active noise cancelation, acoustic noise canceling, dynamic range compression, and automatic gain control. The algorithms learn based on the scenarios and customer needs and optimize them to offer the best user experience.

"Audio is very subjective and highly depends on the form factors the user has at hand and the user's auditory system needs," Khanduri said. "The machine learning algorithms are designed to determine the ambient conditions, acoustics, and user needs and then extract the desired features from the mixed signal." 

Daniel Davis, the president of the audio company BEACN said in an email interview that computational audio has become ubiquitous. "From listening to your favorite song to talking with a friend on your cell phone, the sound at some point along the way is transformed into a digital signal, processed and enhanced in some way, and then transformed back to an analog audio signal that we can hear," he added. 

Users carry around portable devices with computational abilities that rival professional systems from as recently as a decade ago, James Abbott, the Music Industry & Technologies Chair at Syracuse University, told Lifewire via email. He said that smart audio devices at home could listen and adjust sound processing that adapts the audio content to the room's acoustics, improving sound quality from tiny speaker drivers. 

"Our phones have the ability to process music produced in immersive audio formats and reproduce it over our earbuds with the immersive format's 360-degree sound localization intact," he added. "Voice assistants can understand what you are saying regardless of how loud you are playing your favorite music; the algorithms are intelligent enough to discern your voice through almost any background noise level."