Insulation

The electrical behavior of the dielectric (insulating material) is especially important in low level cables. Dielectric involvement (the way in which a particular material absorbs and releases energy), is a major source of distortion in a low level cable. Dielectric constant, the most often quoted specification for insulating material, is actually not very helpful in understanding the audible attributes of different materials. The coefficient of absorption value is more relevant, and the dissipation factor and the velocity of propagation are even more useful.

Air is the ideal “insulation”, so the best cables use as much air as possible. Solid materials all affect the signal, and are best chosen for the nature of their distortion, for having a lack of discernible character. “Low loss” is not itself important, as the little bit that is lost is not heard.

The energy that is stored and then released back into the conductor is out of phase. This will either rob intelligibility (be dull) or add irritation (be bright). Which material is used and how it is applied will dramatically affect the performance of a low-level cable.