Balanced Lines

Do you know the difference between a balanced line and an unbalanced line? If we’re talking about analog audio, this difference between balanced and unbalanced is also the difference between consumer products, which are almost always unbalanced, and professional, which is almost always balanced. To go into the details of these differences would take a number of blogs, so I’m going to try and condense it here.

If you want to know more details, just invite me out to speak at your local group. Are you a member of the Society of Broadcast Engineers? Perhaps you joined the Society of Motion Picture and Television Engineers or the Audio Engineering Society. All three of these, and many other similar organizations, have local groups and often have lunch or dinner speakers. I would be delighted to fit you in my schedule and come give a presentation on balanced lines or many other subjects. Read more »

Analog Audio Hangs on in Broadcast

You hear it everywhere: The world is going digital. But, hold on there, that might be true for video, but it’s not true for audio. Just go visit the major networks in New York or LA. The majority of consoles they’re running are still analog. Look in any broadcast or pro-audio catalog. Analog audio consoles still outsell digital audio by some huge number. And it’s no wonder. The performance of analog cable was never a problem.

The limits in analog are based more on the boxes (preamps, consoles, distribution amplifiers) than on the cable itself. As long as you have reasonably low capacitance in the cable, at around 30 pF/ft. or 100pF/meter, you can go very far without significant loss. The real distance determinator is the source impedance of the device feeding that audio line. If you can get down to 100 ohms source impedance, you can go over 1,000 ft. (300m) before you’re even 1 dB down at 20 kHz on that 30pF/ft. cable. Read more »

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