These are mainly offered for speaker cables and power cables. Their operating principle is a combination of reducing
You can easily try this for yourself by making supports from cardboard or a similar material. I also use this principle for interconnects to keep sufficient distance from metal surfaces and power cables. About 5 cm above the floor should be enough.
Some power-cable manufacturers fit conspicuous blocks around their cables. These are clip-on ferrites designed to stop radio-frequency interference from travelling along the cable, and they can bring a noticeable improvement. They can be added without opening or soldering the cable and cost only a few euros from electronics suppliers. Here is an example from Reichelt. This is certainly worth trying. One high-end power-cable manufacturer uses not just one but several, depending on the model and price range.
Ground loops, and conductor loops in general, are unfortunately not treated as the major subject they should be in high-end audio. They prevent a system from playing freely and reproducing fine detail. Spatial depth is only partly perceptible and the loudspeakers never quite disappear. The subject is difficult for beginners to understand, and even experienced listeners struggle to locate these duplicated connections. Conductor loops most commonly arise through the protective-earth contacts of two devices, but they also occur in widespread RCA and XLR connections, where left and right channels each have a ground conductor, and even inside expensive equipment whose ground potential was not arranged in a star topology. Let us begin with the basics: a voltage is induced in every conductor exposed to a changing magnetic field, creating an electric field. If the ends of that conductor are joined to form a loop, an equalising current flows. Since every conductor has resistance, this current causes a voltage drop according to Ohm's law. That voltage drop can mix with the music signal and degrade it. ... to be continued ...