Downsides of Using Shielded Speaker Cables: A Comprehensive Guide
While shielded speaker cables offer several advantages such as reduced electromagnetic interference (EMI) and radio frequency interference (RFI), it is essential to weigh the potential downsides before making your decision.
Cost
One significant downside of using shielded speaker cables is their higher cost compared to unshielded cables. This factor can become particularly relevant when dealing with large installations, where the additional expenses might add up quickly. If budget is a concern, this could be a compelling reason to opt for unshielded cables.
Additional Cable Thickness and Stiffness
Shielded speaker cables are often thicker and less flexible than regular speaker cables, which can make installation in tight spaces or routing around corners more difficult. This increased thickness may also contribute to the overall weight of the setup, making it more cumbersome to handle.
Overkill for Short Runs
In many scenarios, the benefits of using shielded cables do not justify the additional cost and complexity for short runs or environments with minimal interference. Shielding provides protection against interference, but for setups where this is not a significant concern, the extra cost is unnecessary.
Ground Loop Issues
Shielded cables can create ground loops if not properly grounded, leading to the introduction of hum or noise into the audio signal. A ground loop occurs when two devices are connected through an earth point, and the ground levels are at different points, thereby creating a path for a signal to flow as a hum. Passive speakers are not typically grounded, making it impossible for a ground loop to form. Therefore, shielding cables specifically for grounding purposes is not necessary for audio systems.
The Antenna Effect of Shielded Cables
A more minor but noteworthy issue is the potential for the shielded cable to act as an aerial/antenna. In a grounded cable, the shield is effectively a long wire grounded at one end. This can lead to the cable acting as an antenna, either receiving or radiating electromagnetic interference (EMI). Given that the purpose of shielding is to reduce interference, having a component of your system that can act as an antenna seems counterproductive.
Cases Where Shielding May Be Needed
The only situation where shielded speaker cables might be necessary is when they are running next to more sensitive low-voltage cables for long distances. In this case, proper bonding at both ends ensures that the speaker signals do not bleed onto adjacent low-voltage cables. However, if the shielding is not effectively addressing this issue, it might as well be considered unnecessary or even harmful to the system.
In conclusion, while shielded speaker cables can be beneficial in certain environments, they are not always the best choice. The decision ultimately depends on the specific application and the potential downsides mentioned. For audio setups with minimal interference and short runs, unshielded cables might be a more practical and cost-effective solution.