Long, unshielded speaker wires can be a potential culprit for introducing hum into a sound system, but it is not always the primary cause. The presence of hum in a sound system can be attributed to various factors, including improper grounding, electromagnetic interference, ground loops, or faulty equipment. However, long, unshielded speaker wires can act as antennas and pick up electromagnetic interference, leading to the introduction of hum into the audio signal.
When long speaker wires are exposed to electromagnetic fields, such as those generated by power cables or other electronic devices, they can act as antennas and capture that interference. This interference can then manifest as an audible hum in the audio signal. Shielded speaker wires, on the other hand, are designed to minimize this electromagnetic interference by incorporating shielding to block or minimize the impact of external electromagnetic fields.
While long, unshielded speaker wires can contribute to hum, it is important to consider other potential causes as well. Grounding issues, such as improper or missing grounding connections, can also introduce hum into a sound system. Additionally, ground loops, which occur when there are multiple grounding paths with slight voltage differences, can cause hum as well.
To diagnose and mitigate the hum in a sound system, it is recommended to take the following steps:
Check the grounding: Ensure that all equipment, including the amplifier, speakers, and audio sources, are properly grounded. Verify that the grounding connections are secure and in good condition.
Separate audio and power cables: Keep audio cables and power cables separated to minimize the chance of electromagnetic interference.
Use shielded cables: Consider using shielded speaker wires and audio cables to reduce the impact of electromagnetic interference.
Eliminate ground loops: If a ground loop is suspected, you can use ground loop isolators or try disconnecting and reconnecting the grounding connections of the various components to identify and resolve the issue.
Test with different equipment: If possible, try connecting different speakers, amplifiers, or audio sources to identify if the hum is specific to a particular component.
If the hum persists after taking these steps, it might be helpful to consult with an audio professional or technician who can further diagnose and resolve the issue.