Wiring Mutichannel audio in a coach

[KaranRai]

Hi I have a project wherein i need to wire 4 stereo channels playing different music in a bus with 32 seats. Each seat should have a module to select one of the 4 channels and listen to it by plugging headphones in a 3.5 mm jack on the seat module. We have built the music system with 4 stereo outputs and we have also created a small seat module with amplifier which takes in stereo input and sends out amplified stereo output. Now I need help with distributing the audio. If I connect the 4 channels to the 8 wires on a CAT5 cable and run it across the bus, drawing out a parallel connection for every seat and also run 2 seperate wires along for power and ground, which are also drawn out for each seat module, would this method work? Is there a better way to distribute multiple channel audio across 32 seats in a cost effective way?

Update: the input impedance of the amplifier circuit at the seat units is 150k ohm and the length of the bus is 10m. (Around 25m cabling) Would the voltage drop be significant and would it require another amplifier / repeater ?

 

[noidea_77]

A parallel connection for every seat will reduce the impedance to zero and destroy the music system. On the other hand, wiring the cat5 to all the seats, will increase the resistance and reduce the voltage you get on the last seat to zero.

 

[KaranRai]

A parallel connection for every seat will reduce the impedance to zero and destroy the music system. On the other hand, wiring the cat5 to all the seats, will increase the resistance and reduce the voltage you get on the last seat to zero.

Thanks for your reply. As further information: the input impedance of the amplifier circuit at the seat units is 150k ohm and the length of the bus is 10m. (Around 25m cabling) Would this still reduce the impedance to 0? Would the voltage drop be significant and would it require another amplifier / repeater ?

 

[noidea_77]

Well, it's a bit difficult to provide all the details here, especially because English is not my mother tongue. You may want to ask a local electrician. The problem with the cable length is not the native length in meters, but the massive soldering, that adds resistance to it. Especially the mechanical switches at every seat will do that. Bottom line: professional audio distribution systems use digital signals to the seat and some sort of mp3 players are build into the amplifier/channel switch at the seat for that reason.