How to convert Stereo RCA to XLR?

Question

I am extracting HDMI audio using an optical Toslink + L/R Stereo Analog Converter (VHD-H2HSAs),

then using a Y patch cable XLR Male to 2 RCA Male (Seismic Audio-SA-Y6-6 Inch Splitter) I connect to my mixing board

The mixing board is hooked up to an amp and two large passive speakers.

The result seems to be that I only get half of the audio signal playing through both speakers simultaneously (don't know the proper terminology, but when I listen to a song, the lead guitar might be missing for example).

Do I need different cables to fix this, or can I change settings somewhere along the line?

My mixing board has XLR, TRS, and RCA inputs. I would like to know for sure that I will get full audio before purchasing any more cables to experiment with.

Answer 1

The splitter cable you're using combines the 2 stereo inputs into the 3 pin XLR connector, putting the left channel in pin 2 and the right in pin 3, or the other way around. You can only use that type of connection with a system that specifically uses XLR type connectors for stereo signals.

That's not the case with normal performance and PA devices, where the XLR connectors are used to carry a single channel balanced signal.

In an balanced connection, the input device will subtract the inverted polarity signal from the normal polarity signal in order to get the proper signal for that channel.

So, when feeding your stereo signal to a balanced XLR input, you're subtracting your left channel from the right (or ther other way around) and that's what you're feeding to your amp. Only audio components that are different in each of the stereo channels will be audible, everything that's equally panned to both channels will disappear.

If your mixer only has (balanced) XLR inputs (otherwise, as has been pointed out in some comments, the simplest way would be to use the RCA or Jack line level inputs), what you need is to feed each channel of the stereo signl to a separate XLR input. Since you don't have a balanced signal to begin with, you will have to feed the signal to pin 2 of the XLR connector and leave pin 3 disconnected.

Since you already have one Y cable, you can do that with another of these Y cables. Find out wich RCA connector is connected to pin 2 of the XLR connector and use that one in both Y cables (just leave the other RCA connector free in both Y cables, taking care not to let its contacts touch anything, to avoid interferences). You can also get a pair of passive converters like this one and use normal RCA cables for more flexibility in physically positioning the pieces of equipment.

I'm assuming that the stereo source will be positioned near the mixer. If that's not the case then Edwin van Mierlo's recommendation of using an active device with a balanced output is applicable. A balanced connection, due to it's greater noise immunity and stronger signal in the receiving end, is highly advisable for any distance greater than 10 meters.

Anyway, connect each output XLR connector to a input channel on your mix and hardpan each of these two channels left and right as required to recover the original stereo panning.

Answer 2

I would not use the Y-cable as indicated.

For the best solution, albeit a bit expensive, I would use a DI, with 2 RCA in, and 2 XLR out.

The advandtages of the DI would be:

• ground isolation (lift) to avoid ground loops and hum
• level adjustment between consumer grade equipment and pro audio (with and "active" DI)
• unbalanced (RCA) to balanced (XLR)
• attenuation if needed, most DI boxes have attenuators/pad's
• impedance matching, RCA unbalanced out is likely to be high impedance, while XLR in of the mixing desk will expect low impedance

There are various DI's on the market, both "active" as "passive" with different price tags and different specifications. Active DI's will require a power source/supply.

Search around on the internet there are lots of tutorials about DI boxes, their use, and explanations.

An example of a passive DI would be this, which would be used by DJ's to do exacltly what you want to do; connecting consumer equipment to pro audio. (I am not affiliated with product/brand nor website, this is only an example)

You would then use 2 channels on your Mixer, one pan left, one pan right, this would be the simplest.

Depending on your Mixer you can use a stereo channel if it has one, or group 2 mono channels into a stereo group. The routing after that is all dependent on how you setup your channels/mixer/features.

HTH.