Audio Systems: tv

Question
Hi I'm having issues.
I really hope you can help.  My friend is hearing impared and we purchased a set of rf headphones that used to plug in with rca cables to the back of our older tv.  Now, we had to buy a flatscreen which has only one audio out that says coaxial digital.  I purchased a y cable with two female, on male jack and plugged it in.  No sound at all.  When I plug the tower into the headphone jack, it works but I cannot hear the speakers!  Geez.  What the heck do we do?  the tv has an hdmi slot too.  
Thanks in advance

Answer
Hi Amanda,

The primary issue is that the single RCA output from the TV, labelled "coaxial digital" is sending a digital audio signal, and the RF headphone unit requires an analog audio input (the two red and white RCA connections).

Just a quickie bit of "cable school" concerning RCA cables.... it's not just the cable or the connector type that determines whether of not a functioning connection can be made between two devices... it's all about the SIGNAL TYPE that is being sent through the cable.

First - what you have is a coaxial digital output from the TV. The signal that travels from that output is a data flow that gives a digital receiving circuit all of the multi-channel audio information it needs through a single cable... in other words, you only need 1 cable for 2 channel, stereo audio.
Next - the inputs on the RF headphone device are looking for an analog signal, one channel per connector, which needs 2 cables...  for 5.1 surround sound, you would need 6 cables; for quadrophonic, 4 cables, etc...

The main thrust is that the two signals will NEVER EVER be able to communicate by simply connecting them with a simple cable. It's like trying to play a CD on a turntable meant for vinyl records... it's just never going to work.

In your case, you will need to get a Digital to Analog Converter, otherwise known as a DAC. This is a "little black box" that converts the digital audio from the TV into analog audio for your headphones.

Luckily, these are easy to find, relatively cheap, and simple to use. A Google search for "digital to analog audio" will give you a bunch of options, but here are a few examples:

http://www.markertek.com/Video-Equipment/Video-Processors/Digital-to-Analog-Conv

http://www.markertek.com/Video-Equipment/Video-Processors/Digital-to-Analog-Conv

http://www.rakuten.com/prod/analog-rca-stereo-to-digital-optical-toslink-coax-au

I really hope this helps you out. Cheers!