John,
Since a speaker is essentially a linear electric motor it works only if the voltage and current vary creating a magnetic field analogue to the waveform - hence the current is alternating according to frequency of the signal.
The voltage at the amp output varies from + to - and as such is AC.
AC doesn,t just apply to power cords, but also to the input of speakers. Ever do the poraity check on speakers? One applies a 9 volt cell (DC) to the terminals and watches in which direction the cone moves and stops. The cone moves back and forth in sympathy with the varying voltage and therefore the voltage must alternate between + and - for the cone to respond to the frequency changes.
That is why direction on AC current carrying lines makes no difference, since the current is always reversing itself with the frequency.
Salut, Bob P.
Since a speaker is essentially a linear electric motor it works only if the voltage and current vary creating a magnetic field analogue to the waveform - hence the current is alternating according to frequency of the signal.
The voltage at the amp output varies from + to - and as such is AC.
AC doesn,t just apply to power cords, but also to the input of speakers. Ever do the poraity check on speakers? One applies a 9 volt cell (DC) to the terminals and watches in which direction the cone moves and stops. The cone moves back and forth in sympathy with the varying voltage and therefore the voltage must alternate between + and - for the cone to respond to the frequency changes.
That is why direction on AC current carrying lines makes no difference, since the current is always reversing itself with the frequency.
Salut, Bob P.