Well i was just wondering if we could hear sound in space without using the normal radiowave method. I was just thinking if water would conduct sound - hydroacoustics- as it does on land, in space and a device present which converts the sound waves in water to audible sound, which is then transferred using headphones to the astronauts ears. It may not be as convenient as radio waves, but would surely just transmit sound waves without using radio waves, like when astronauts are talking to each other. This would prevent the harmful effects of radio waves, clearly seen in this thread: http://www.otherhealth.com/homeopathy-discussion/2358-radio-waves-harmful.html.

So basically, how this thing would work is that an astronaut speaks into a small tube, connected to a vessel containing a limited amount of water. Sound would travel through water, the converter would convert sound waves in water to audible sound waves, which the other astronaut/s can hear through headphones. Or else, the astronaut who has to convey the message, can speak into a mic which sends signals through water, without the use of any radio waves.

will be attaching an illustrative description soon.