How to get “big” audio from small speakers in ultrathin lap.

The workplace environment continues to see unexpected and ongoing changes in how people use their laptops. Hybrid working has elevated the importance of audio during laptop conference calls, especially in noisy environments. These changes in worker environments require an easy-to-transport laptop with a great audio experience free from headphones and external speakers.

Hybrid working environments are accelerating the adoption of ultrathin laptops, with some approaching 10-15mm—the same thickness as mobile phones. This move to slimmer, lighter laptops, along with the rise of novel laptop form factors such as 360s, detachable 2-in-1s, and folios, means that acoustic challenges are also becoming more complex.

As PC manufacturers introduce new multi-speaker laptops that are thinner than ever, smart amplifiers are at the center of smart designs that are driving and resolving these audio engineering challenges.

Laptop-speaker audio design challenges

Today’s ultrathin laptops are used in a variety of ways and conditions that demand consistent high-quality audio. This means that the speakers inside these ultrathin notebooks must get smaller and thinner. However, the limits of physics make it difficult to get loud sound and bass from these micro speakers. In all situations, the audio should also be consistent. However, constantly shifting positions and changing environments can present challenges that dramatically impact the laptop’s audio consistency.

Cirrus Logic enables fine-tuning for each mode and accommodates varying acoustics, ensuring consistently loud and high-quality audio for laptop, tablet and tent mode use cases.

For instance, users may choose to listen to 2-in-1s in tablet mode, tent mode, or laptop mode. In addition, low battery charge can cause conditions that limit audio loudness. Other use cases that impact the consistency of the laptop’s sound quality include different volume levels and the type of audio content, such as voice, movies, music, and games. Lastly, the audio quality should hold up over time without noticeable speaker degradation or failures. Each of these use cases has different acoustic and electrical challenges.

The demand for great speaker audio is spurring OEMs to turn to smart amplifiers as the go-to technology. Smart amplifier technology extracts the best audio performance from the laptop’s acoustically challenging design. achieve high-quality audio output signals, laptop designs must have full bass, low distortion, balanced sound, and limited rattle and vibration. A smart amplifier combines hardware and software to maximize loudness, quality, and consistency while minimizing rattle and protecting speakers from damage.

However, driving a speaker to maximum loudness is a delicate balance. If driven too far, the speaker will distort or even suffer permanent damage. Cranking up the volume can also cause the speakers, keyboard, chassis, and other components to rattle. The user hears this rattle as distortion and can feel unwanted vibrations. In the worst cases, the manufacturer prevents rattling by turning down the volume, compromising the audio greatness, loudness, quality, and consistency, and thus reducing the overall movie or gaming experience.

The big challenge is to make a single ultrathin laptop sound good under different uses and conditions. The audio signals must sound consistent for different content types, such as voice, music, and games, and at different volumes and battery levels. The audio quality should also be consistent over time for these devices, without noticeable speaker degradation or failures.

DSP smart amplifiers optimize PC audio

Smart amplifiers solve these challenges by combining an amplifier with an integrated digital signal processor (DSP) that runs intelligent algorithms with speaker physics models to maximize speaker performance and consistency. This processor, combined with the speaker sensing hardware, allows the amplifier to push the speaker further while—at the same time—protecting it from damage. Compared to basic amplifiers, smart amplifiers can achieve 2X or more sound pressure level (SPL).

In addition, OEMs combat loudness limitations in ultrathin laptops by using new cutting-edge speaker types designed to extract better audio. These include high-excursion and dual force-cancelling speakers, which need smart amplifiers with high drive strength to execute maximum performance. For example, high-excursion speakers require a powerful, high-voltage smart amplifier to achieve louder audio and higher dynamic range, while new dual force-cancelling speakers rely on powerful, high-drive strength smart amplifiers to provide a listening experience with low rattle, low distortion, high dynamic range, and bass loudness.

Enhancement algorithms maintain high-quality audio

Everyone’s definition of audio quality differs. Generally, however, universal care-abouts include loudness, low distortion, balanced response, transparency, and less rattle. Smart amplifiers help drive micro speakers to their limits in the bass regions and, in many cases, extend the frequency range for deeper bass. A balanced or “flat” response is possible when no single frequency range, such as low, middle or high, is dominant. Implementing this strategy through on-chip algorithms makes for a more pleasant sound.

Low distortion helps clarity and intelligibility, especially for voice calls. Enhancement algorithms help balance the speaker’s response by measuring that response in order to cancel out any unwanted peaks or valleys.

Rattle is a dynamic and tricky audio problem. Certain content like ring tones and human voices may excite audible rattle, while other content like pop music may not trigger such an effect. When the speaker vibrates, it can cause a knock-on effect where other parts of the system, like the keyboard or chassis, will also rattle. This unwanted vibration can create a bad user experience, and the user may even perceive the vibration as audio distortion, which degrades clarity and intelligibility.

Cirrus Logic smart amplifiers with on-board signal processing can enable higher quality with enhancement algorithms. For example, a dynamic bass extension algorithm maximizes bass loudness and depth for any volume level. A fast-tuning change feature optimizes sound quality for each different deployment mode, such as tablet, tent, or laptop modes. Finally, a battery management algorithm adjusts tuning as battery voltage falls to maximize loudness and minimize distortion.

Support for the MIPI SoundWire interface

At the same time as laptops are getting thinner, the industry is transitioning to a new SoundWire interface for simple integration with a SoundWire Device Class Audio (SDCA) host. SDCA will make the integration of audio components simpler by providing a common way to describe audio components of the same class with reduced software overhead and complexity.

The SoundWire interface helps developers add intelligence to audio devices without unnecessary software complexity, thereby allowing these products to be brought to the market faster and at lower cost. Designing in a smart amplifier with software capabilities to support this change will ease the transition for OEMs and enable them to deliver a better user experience.

Smart amplifiers propel laptop audio

With current mobility and remote working requirements, laptop audio has become part of our personal and business lives. Dramatically reducing laptop sizes to ultrathin, lightweight, and flexible form factors complicates the audio challenges associated with remote and mobile user environments.

The newest most innovative laptops use smart amplifiers to extract the fullest design benefits, giving consumers a great audio experience with big sound. Smart amplifiers, executed with advanced algorithms, deliver superior audio quality through multiple speakers to produce an immersive audio experience for movies, music, games, and voice despite today’s demanding mobile user environment.