More of the portable devices that we once operated by the touch of the button can now be activated by our voices. As consumers expect these devices to become increasingly sleeker and smaller, design engineers face a daunting challenge: how to deliver louder, richer sound from speakers that are no larger than a memory card.
Ever since smartphones drove the mass adoption of micro speakers, these tiny speakers have become ubiquitous in everything from wearables to IoT applications. While the components of a micro speaker are similar to those of their traditional counterparts, the devices themselves are obviously much simpler in construction.
All speakers have a maximum power rating. As speakers get smaller, their loudness or sound pressure level (SPL) goes down while the resonant frequency goes up, which leads to less bass. Driving these speakers harder can increase loudness and bass response; however, this approach, if done without proper speaker protection, can easily damage the micro speakers, as it causes overheating and over excursion.
Is there a way to drive micro speakers beyond their maximum power rating, without blowing them out or causing any other damage? There is now. Maxim’s Greg Mow and Michael Tuason have the answer, which they share in their blog post, “How to Get Louder, Richer Sound from Micro Speakers.”