CTS Sample Question of the Week: Aug 26, 2024
Every week we're going to post a question from the CTS Sample Question set. Check back weekly for new questions.
What is the BEST PRACTICE for deciding between unbalanced and balanced audio cables?
a. Use unbalanced for cables under 25’ (7.6 m)
b. Use unbalanced for cables under 30’ (9.1 m)
c. Use balanced for all cables over 50’ (15.2 m)
d. Use balanced for all cables
Update: The correct answer is - d. Use balanced for all cables
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A.
D
D...unbalanced cables can be used for shorter runs, balanced cables are a safer choice overall
d
The best practice for deciding the use of cables depends of the source, if the equipment have balance output and the receiver also have it, the selection must be balanced in both ends, if one of them have unbalanced input/ouput the cable must be unbalanced if the distance is under 25' or better use a transformer bal/unbal.
D
Answer A Use unbalanced for cables under 25’ (7.6 m)
D
d
Use balance for all cables.
d
D, It is always best to use balanced audio connections whenever possible. and use transformers to balance unbalanced devices.
D
D
D
The answer is NONE OF THE ABOVE.
Balanced cables are used for common mode rejection.
A device that has a three wire audio connection such as XLR or TRS contains a circuit that accepts the signal (XLR typically) as
Pin 1 GND (sheild)
Pin 2 +
Pin 3 -
If the device doesn't have a balanced input, then using a 3 wire "balanced" connection wont do anything.
In fact, I have experienced instances where using TRS instead of TS connectors actually can cause problems, especially if someone gets "balanced" confused with "stereo"
Example, using a TRS cable on a stereo output (phone 3.5mm) and pluging it to a balanced input. In that case the Left signal will be trying to cancel the Right signal and the result would be hearing ONLY the stereo information that was from the source. If this was a recorded music track it might sound like its down the hall, that's because your only hearing the Reverb that was recorded in Stereo.
D
Use balanced for all cables
d