But since you are making a Helix XLR cable, would it be possible to try that cable as the AES EBU cable to see if it works?
Unfortunately I have not had the opportunity to explore every possible use for the Helix Geometry.
I found this basic explanation of high frequency transmission problems online...
At high frequencies (people use to say RF for Radio Frequencies) all cables behave (or misbehave) as transmission lines.I do know that a Helix Interconnect cable used for analogue purposes can also be used as a SPDIF cable without using a 75 Ohm RCA plug and it performs extremely well - i.e. better than most purpose built 75 Ohm cables.
Get a long pipe and talk into it, that’s a transmission line. If it is long enough, you’ll hear some echo coming back from the other end. That’s a problem.
Whenever you send some stuff in a transmission line it will always travel at a certain velocity (the speed of sound in the case of you talking in a pipe, the speed of light modulo impedance, dielectric constant etc, in a cable).
So, if your signal is fast enough, that this propagation effects are not negligible anymore, you’ll say it’s a transmission line, and you have to treat it like this. It is not something difficult, just a part of your design.
For instance take a SATA cable. If you send some low frequency signals in it, it’s a cable. If you send 3 billion bits per second in it, it’s a transmission line, since there are several bits in the cable at any given time. Of course you’ll want to minimize echoes if you wanna use that to transmit some useful information.
So if you put a resistor at the end of the cable, which has a certain value, you will get optimal damping and optimal transfer of power : all the power that flows in the transmission line will end up in the resistor instead of bouncing back to the source and messing everything. The value of this resistor is your characteristic transmission line impedance. It can be calculated (depending on geometry etc) or it can be measured.
- Perhaps it’s the Helix Geometry that overcomes some issue in a standard 75 Ohm cable
The Helix Geometry is very different from that of a "standard cable" - so does it suffer from the same reflection issues - or is the highest frequency it can handle without any issues, high enough to handle those supported by a 110 ohm AES EBU connection without any problems?
I would try it - What’s the worst that can happen? - it sounds bad?
But then again - it might not :-)
If you do try it, please post your observations. I like to understand the limitations of the Helix Geometry as well as its good points.
Sorry I could not be of more help - Steve