From Nigel Harper
Talk of directional cables always makes me see the and Feedback’s mention is no exception (27 January). In order for any coil-driven speaker to produce sound it has to push the cone out – and then pull it back by an equal amount.
So the current that drives the speaker is alternating: there is no such thing as a “negative” or “positive” connection. We have red and black connectors on speakers only to make sure that both speakers are connected “in phase” so they push and pull at the same time, and the air pressure waves generated don’t cancel each other out.
Any asymmetry in this push-and-pull process would mean that the loudspeakers would very quickly “bottom-out”, inducing distorted sound as a result of cumulative travel in the direction of supposed directional bias.
Windsor, Berkshire, UK
