Thread: balanced/unbalanced

nick,
All audio has a hot(+) and cold(-) line. With unbablanced, the cold and the ground are combined making a 2 conductor connection (+) & (-). With balanced, the hot (+), cold (-), are seperate from the ground shield (s), for a 3 conductor connection. Additionally the cold side is flipped out of phase at the outputs and then fliped back into phase at the inputs, so any additional noise picked up in the cable is cancelled out. Kurt

thank you. I get it now. Does most equipment use balanced? If not, why not? It seems that balanced is far superior to unbalanced.

Nick

Originally posted by silent_nick:
thank you. I get it now. Does most equipment use balanced? If not, why not? It seems that balanced is far superior to unbalanced.

Nick

Balanced isn't always needed. It is more expensive, involves transformers or additional electronics to accomplish. Short line level +4db runs of 20' feet or so, unbalanced, will not add significant noise in the line. If your rack gear is within these limits you are cool. Unless you are in an extreme RF and Hum saturated place. I said 20', like a round trip from the patchbay, or insert to your gear rack. If it gets longer, you can check for RFI and other noise with a good digital meter.

Mic lines require balanced, if they are high Z unbalanced you will notice noise, and because the impedance is high, after 6' to 10', the resistance of the mic and the capacitance of the cable will start to roll off high frequency, the gain for mic's is higher, and along with that, noise gets amplified too. For mics, stay with Low Z balanced. You can run a hundred feet and be cool.

When using unbalanced +4db rack gear, you should be cool. If you have an all balanced run, and cables, use it.

--Rick

What if you go from balanced XLR to unbalanced 1/4" and back? Example drum OH to RNC comp to board. What connectors/adaptors/cables are best? What I mean is do I use a XLR to 1/4" cable, or a XLR/XLR cable into a XLR/1/4" transformer? Do pros have about $5000 dollars in cables and adapters laying around or what?

Originally posted by downflow:
What if you go from balanced XLR to unbalanced 1/4" and back? Example drum OH to RNC comp to board.....Do pros have about $5000 dollars in cables and adapters laying around or what?

Actually you should not use a mic level out into a line level device, there just isn't enough gain, but I catch your meaning.

Eventually all signals will end up 2 conductor unbalanced at some point. The idea of balanced is to prevent noise build up, and signal loss in cable runs.

For your drum OH mic, you would go to the board, balanced, with your mic and apply the RNC through the direct out into your recorder from the channel strip, or through the channel insert loop which will be unbalanced line level.

I have a junk drawer of matching transfomers, and unbalancing cables and the like, but only maybe a hundred dollars worth of stuff.

--Rick

Originally posted by downflow:
What if you go from balanced XLR to unbalanced 1/4" and back? Example drum OH to RNC comp to board. What connectors/adaptors/cables are best? What I mean is do I use a XLR to 1/4" cable, or a XLR/XLR cable into a XLR/1/4" transformer? Do pros have about $5000 dollars in cables and adapters laying around or what?

The compressor would be inserted at the mixer channel. You would never plug the mic directly in the compressor, for one the compressor has no phantom power for a condenser mic..
In a pro studio, all equipment is intefaced through patch bays with the appropriate balanced or unbalanced wiring accomodated. The way a patch bay works, the cold side of a balanced connection is automaticly connected to the ground shield when a cable is inserted.

So everything in the studio is connected to a patch bay? Once it's patched then it becomes unbalanced since the cold side is connected to the ground shield?

Sort of.. usually the patch bay is balanced. Unbalanced items are hooked up unbalanced and balanced items are hooked up balanced. When you plug a balanced piece into an unbalanced piece, the signal is goes unbalanced. But once you plug into another piece of balanced gear, the signal will once again become balanced. Unbalanced and balanced gear can live and play in the same rack very well. The problem is with different levels. -10dB and +4 gear don't mix so well, making it hard to maintaine a proper gain structure. You need to be aware of differences in input and output levels of your different pieces of equipment. Kurt