bozmillar
New member
I was thinking about this last night on the toilet, and thought I should run it by here before I come to any conclusions.
It seems that in audio signals, the impedance of the cable is completely irrelevant. According to wikipedia, transmission line equations only come into effect when the length of the wire is comparable in length to the wavelength of the transmitted signal.
"In many electric circuits, the length of the wires connecting the components can for the most part be ignored. That is, the voltage on the wire at a given time can be assumed to be the same at all points. However, when the voltage changes in a time interval comparable to the time it takes for the signal to travel down the wire, the length becomes important and the wire must be treated as a transmission line. Stated another way, the length of the wire is important when the signal includes frequency components with corresponding wavelengths comparable to or less than the length of the wire."
Assuming that we are using a copper wire and electricity flows at about 2/3 the speed of light (200,000 m/sec), the wavelength of a 30kHz signal is 6,667 meters long. So unless our cables are 4 miles long, the impedance doesn't matter. Am I the only person who didn't know this? or am I missing something?
It seems that in audio signals, the impedance of the cable is completely irrelevant. According to wikipedia, transmission line equations only come into effect when the length of the wire is comparable in length to the wavelength of the transmitted signal.
"In many electric circuits, the length of the wires connecting the components can for the most part be ignored. That is, the voltage on the wire at a given time can be assumed to be the same at all points. However, when the voltage changes in a time interval comparable to the time it takes for the signal to travel down the wire, the length becomes important and the wire must be treated as a transmission line. Stated another way, the length of the wire is important when the signal includes frequency components with corresponding wavelengths comparable to or less than the length of the wire."
Assuming that we are using a copper wire and electricity flows at about 2/3 the speed of light (200,000 m/sec), the wavelength of a 30kHz signal is 6,667 meters long. So unless our cables are 4 miles long, the impedance doesn't matter. Am I the only person who didn't know this? or am I missing something?