a power and splitter question

[canadave]

Hi folks, I have a question about whether it's okay to split audio out from a power perspective. Let me explain.

We currently broadcast by running a single audio cable from our on-air PC's green "Line Out" jack to our transmitter. I want to split that audio cable using a basic Y-splitter, so that one output goes to our transmitter as normal, and the other output goes to another PC's audio input, which will be used to stream that audio online to the Internet.

When I raised this possibility to our consultant engineer, he said we shouldn't do that, because it would attenuate the audio signal at the transmitter somehow. I think he said it was something to do with power draw or something like that.

Does that sound plausible? I just can't understand how taking a single PC audio-out cable and creating a split setup with a Y-splitter would cause a drop in signal at the end of one of the outputs (as compared to if I'd left it alone as a single cable).

 

[Chuck]

Hi folks, I have a question about whether it's okay to split audio out from a power perspective. Let me explain.

We currently broadcast by running a single audio cable from our on-air PC's green "Line Out" jack to our transmitter. I want to split that audio cable using a basic Y-splitter, so that one output goes to our transmitter as normal, and the other output goes to another PC's audio input, which will be used to stream that audio online to the Internet.

When I raised this possibility to our consultant engineer, he said we shouldn't do that, because it would attenuate the audio signal at the transmitter somehow. I think he said it was something to do with power draw or something like that.

Does that sound plausible? I just can't understand how taking a single PC audio-out cable and creating a split setup with a Y-splitter would cause a drop in signal at the end of one of the outputs (as compared to if I'd left it alone as a single cable).

It will probably work fine, but good engineering practice would be to take the output and run it into a distribution amplifier that has isolated feeds for your transmitter and streaming computer. That said, try the Y-cord. If the results are satisfactory, then problem solved...

 

[Info-warrior]

It's all about load impedance. Impedance is like resistance except can be frequency dependant. For audio systems though, we really don't need to worry too much about that.

Audio systems used to be real fussy about impedance. At one time audio inputs were 600 ohms and the output of the device feeding them expected to see the 600 ohm load. If you were to split the signal, the load impedance would be too low, and distortion and attenuation would result, some devices might even be damaged by too low a load impedance.

Today, however, devices are much more forgiving. Most devices today are voltage fed. The impedance at your soundcard output is very low, maybe around 50 ohms or so, and the input on you PCs soundcard is very high, say around 10,000 ohms. The input for your Transmitter's stereo coder could be anywhere from 600 ohms and up. I've split signals 2 and sometimes 3 ways for recording purposes and never had an issue with insufficient levels.

Bear in mind, I'm not an engineer, I'm just a hobbyist, and as such wouldn't advise you to go against the advice of a professional. Some potential problems I could see, if the PC your feeding audio into is switched off, there could be an affect on the quality of signal. If the cables become disconnected from the PC the signal to the transmitter is suceptible to hum and noise pickup.


I suppose if eases everyone's mind, a second sound card could be added to the source PC cheaply.

I too am interested in what the pros in the field have to say on the matter as there are likely fine details I'm missing.