Apple is reportedly testing a new ‘porous coating’ for iPhone and iPad’s speaker that could massively improve both its quality and loudness.

A new patent granted to Apple today by US Patent & Trademark Office suggests that the company is testing new material for iPhone and iPad’s speaker, as well as a new positioning, that could significantly improve its performance.

Currently, how iPhone’s speaker contains two elements. The main speaker driver that converts electrical signals into audio, and the ‘back volume’, or the space through which sound travels. There are certain forces exerted on the sound during its travel from the main unit, in the back volume, which makes it louder.

Naturally, increasing this area and the forces exerted on the sound generated would increase the volume, but in devices like iPhone and iPad, where keeping the device’s thickness as minimum as possible is the goal, this option becomes irrelevant.

Apple’s patent discusses a ‘highly porous acoustically active coating’ on the back volume that would result in a massively improved speaker system. The coating is ‘highly porous,’ and Apple describes it as ‘having a thickness and including between 2% and 30% by mass of a binder and between 70% and 98% by mass of a zeolite.’

The other way discussed in the patent is by placing absorbent materials like carbon black into the back volume. Apple says that ‘such materials can virtually increase the back volume— in other words, their presence in the back volume enhances loudspeaker performance as if the speaker’s back volume had been made physically bigger.’

Apple has been granted a lot of patents over the past few months. The company is also said to be testing a new technology that could significantly improve autocorrect on iPhone. On the other hand, Apple is also said to be testing Mac Pro’s cheese grater design for iPhone.