Two patents granted to Apple this week reveal that the iPhone maker experimented with waterproof speakers and microphone-enabled headsets that recognize a user's voice using bone vibrations, according to AppleInsider.

The first patent, filed in 2013, is for a set of earbuds with a super-sensitive accelerometer that can sense when someone is using their vocal chords by measuring the vibrations in the bones and tissue of the wearer's head.

According to the patent authors, the bone-sensing microphone's primary objective is to improve voice quality. Signals from the accelerometer are combined with acoustic signals from the microphone to produce a high-quality voice reproduction.

The accelerometers would be located inside the earbuds, while multiple microphones would be placed along the headset cord. The microphones are multidirectional to capture both the wearer's voice and the ambient noise, such as wind, to filter out.

The second patent is welcome news to people (mostly men, according to a study) who are prone to dropping their iPhones in toilets. Filed in 2014, it grants Apple rights to a water-resistant housing for speakers.

It's no ordinary waterproofing, though. The exterior of the housing is coated with a hydrophobic material as a first line of defense, but the housing can also detect when it's been filled with water and direct the speaker to produce a series of tones whose vibrations and pressure will expel the liquid.

Patents don't always turn into products, but Apple does have a vested interest in waterproof speakers since expanding its mobile lineup to include the Apple Watch. Owners of the first-gen model can wear their watch while exercising and in the rain, but Apple says it's not designed for swimming or showering.