12 AWG Speaker Wire with an Impedance of 100Ω - 150Ω

[RickB]

I just thought of the AES/EBU standard used in digital devices, it's a 110 Ohm balanced type connection:

AES3 and AES3id - Short and Long Distances​

AES3 uses 110 ohm shielded twisted pair (STP) cable with XLR connectors up to a distance of 100 meters. AES3id uses 75 ohm coaxial cable and BNC connectors for up to 1,000 meters. "Unbalanced" coax is better for long distances than "balanced" twisted pairs.

********************************************************************************

Aes Ebu​

2018-04-05 By WikiAdmin Leave a Comment

The digital audio standard frequently called AES/EBU, officially known as AES3, is used for carrying digital audio signals between various devices. It was developed by the Audio Engineering Society (AES) and the European Broadcasting Union (EBU) and first published in 1985, later revised in 1992 and 2003. Both AES and EBU versions of the standard exist. Several different physical connectors are also defined as part of the overall group of standards. A related system, S/PDIF, was developed essentially as a consumer version of AES/EBU, using connectors more commonly found in the consumer market.

Hardware connections​

The AES3 standard parallels part 4 of the international standard IEC 60958. Of the physical interconnection types defined by IEC 60958, three are in common use:

• IEC 60958 Type I Balanced – 3-conductor, 110-ohm twisted pair cabling with an XLR connector, used in professional installations (AES3 standard)
• IEC 60958 Type II Unbalanced – 2-conductor, 75-ohm coaxial cable with an RCA connector, used in consumer audio
• IEC 60958 Type II Optical – optical fiber, usually plastic but occasionally glass, with an F05 connector, also used in consumer audio

 

[Capitol C]

As I said before, "You might think so, but no, the impedance of parallel conductors is largely frequency independent."
Impedance of an inductor or capacitor is related to frequency, like in speaker coils and crossovers, but not when it comes transmission line, as a TL is essentially a series of inductances and capacitances. At audio frequencies this barely matters as the wave lengths of the audio signal are very long compared to the wire run, in this application it's more about DC resistance. At radio frequencies it matters because you can have several complete cycles of a signal on the TL simultaneously, going to a load. Here's a calculator that can be used to estimate the impedance of a variety of transmission line arrangements: https://www.mantaro.com/resources/impedance-calculator.htm
Here's a decent video about the topic of transmission line impedance:

I need the strength of aluminum is actually desirable in my application since the wire will be under some tension and aluminum might limit the stretching. Also, at the frequencies I'm using it for, current travels on the surface of the wire, known as the "skin effect". Audio frequencies as so low, again, compared to the line length in most applications, that speaker wire can be treated more like a DC application.

Spot on!