Here at Sweetwater, we know that choosing the right cable for the right device can sometimes be tricky. Sweetwater’s Cable Buying Guide should demystify some of the confusion surrounding cables, how they work, and which ones connect to what. With so many different connectors out there, it has become more and more important to understand which cable is the appropriate choice. Although this is an excellent reference, if you are ever in doubt, Sweetwater’s Sales Engineers are cable experts and can help you make the right decision. Just call (800) 222-4700!
Balanced vs. Unbalanced Cables
A balanced electrical signal runs along three wires: a ground, a positive leg, and a negative leg. Both legs carry the same signal but in opposite polarity to each other. Any noise picked up along the cable run will typically be common to both legs. Assuming the destination is balanced, the receiving device will “flip” one signal and put the two signals back into polarity with each other. This causes the common noise to be out of phase with itself, thus being eliminated. This noise cancellation is called “Common Mode Rejection” and is the reason balanced lines are generally best for long cable runs. XLR and TRS cables are used to transmit balanced audio from one balanced device to another.
Unbalanced cables are less complicated, but they’re much more susceptible to noise problems. In general, unbalanced lines should be kept as short as possible (certainly under 25 feet) to minimize any potential noise that may be carried with the signal into the connected equipment. You may be able to hear a difference in the signal when cable lengths exceed 17 feet.
Common Cable Connectors Explained
In the audio world, there are six common cable connectors: TRS and XLR for balanced connections and TS, RCA, SpeakON, and banana plugs for unbalanced connections.
TRS is the abbreviation for “Tip, Ring, Sleeve.” It looks like a standard 1/4″ or 1/8″ plug but with an extra “ring” on its shaft. TRS cables have two conductors plus a ground (shield). They are commonly used to connect balanced equipment or for running both left and right mono signals to stereo headphones. You will also find TRS connectors on the stem of Y cables. These are used for mixer insert jacks where the signal is sent out through one wire and comes back in through the other.
XLR connectors are 3-pin connectors: positive, negative, and ground. They are usually used for transmitting microphone or balanced line-level signals. In audio, you will typically see XLR cables connecting microphones to mixers and connecting various outputs to powered speakers.
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I want to set up a camera and microphone to record a noisy neighbor who has been deliberately slamming his door in my apartment building. Camera and microphone will be mounted somewhere just outside my door. If cables are required, they'd have to be thin enough to fit between a door and a doorframe, very snug space.
The neighbor is maybe 12 feet away from my door, the hall is reasonably well-lit. Ideal situation would be to record it all with a time and date stamp, on my computer.
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