Star-quad has a real benefit and I use it when that benefit is tangible. Canare has been making professional star-quad speaker cables continuously for nearly 50 years.
No one is saying anybody else has to use it, so I do not understand your expressed outrage.
No one is saying anybody else has to use it, so I do not understand your expressed outrage.
My point is that you omitted the specifics.
There is for speaker cable.
This is an interesting thing.
I have been giving assistance to beamline scientists at work related to noise intrusion into their picovolt measuring systems. They were complaining that the motion control system was causing system noise when the system was turned on, not even moving the steppers but just turning the system on.
I pointed out that the motor drive was a pwm system running 19khz, with a 2Khz position update rate, with 48 volt spikes to charge the inductance of the stepper coils for high acceleration/velocity capability.
The motor coils have a capacitance to the motor frame, and any frame currents from that capacitance has to return to the drive amplifier, and will do so via the framework of the experimental apparatus. I detailed how to provide a low impedance frame ground going back to the amplifier to keep current from going through the experiment.
I never thought about the speaker coil to frame capacitance as an issue, but am fighting this specific battle in the workplace. Hence I found this comment interesting.
Jn
I've been using star quad speaker cable for the last 20 years for 2 reasons
1. It was free
2. Handy for bi-wiring if you want to.
Unless it corrodes can't see me buying any more speaker cable in the future.
Can't see how that would happen in a speaker though. Speakers are generally (but not always) made of insulating material and not grounded so the only way back to the drive amplifier is via the cable. Kirchoff should be happy?
This would be like a steel chassis in the speaker and the phono stage/mic preamp bolted to that chassis?
So, out of curiosity, where is the system you refer to? So I can try and find some information specific to it? 🙂
Here is one way to think about the problem: The impedance at the terminals of a transmission line is resistive for a lossless line. Let's assume the lines in the problems are lossless, at least for now. The impedance at the terminals will look like the characteristic impedance until such time as reflections from impedance discontinuities along the line propagate back to the terminals. In this case there is only one discontinuity, either a short or an open at the end of the line.
Okay. At t=0 when the switch is closed and before any line reflections return, the circuit is equivalent to a switch, a battery, a light bulb, and two resistors all in series. Depending on things like the battery voltage, the resistance values, and the bulb characteristics, the bulb may or may not emit light when the switch is closed. Let's say for the sake of argument that it produces a dim glow, meaning it is lit up.
During that initial period of time, it doesn't matter of the lines are open or shorted at the ends. The bulb sees the exact same series resistance in either case.
Now let's consider what happens later. Energy does not travel down the lines at C, the velocity of light in free space. The propagation velocity of a wavefront in a transmission line is generally less that C. So if the lossless line is one light year in length, it will be more than two years before we get a return reflection telling us if the lines are open or shorted. How the lines settle after a few reflections is hopefully obvious by now. If not, maybe time to review TDR principles.
...As an aside, on the topic of speaker wire, jonhmath is right about star quad. Its not fad, some people are just claiming it is. That some of those people commonly tend to be overconfident in their views does not mean they are right. Overconfidence is a feeling, much like an emotion, nothing more.
Last edited:
Perhaps you need to re-read the article more carefully. The sole purpose of the three visible steered arrays is for sound reinforcement to the chamber. The steered arrays for the gallery are not in the chamber or even visible, they are hidden flush mounted in the ceiling of the gallery.
You are entirely correct, speakers will not have a parasitic path. I've not seen any analysis of the capacitive aspect of the VC to frame, so also do not know where the vc L/C would resonate, nor if it would matter.
jn
The steered system you have been talking about, of course... For example, post #52.
I've been talking about steered arrays in general in several posts. In #52 I referred to one where the directionality was completely screwed up by cross-coupling between incorrectly paired conductors in the multi-core speaker cables. That installation was the parliament house in Darwin, which coincidently happened to be the system I linked to in #72 as an example of the kind of system with steered arrays I was talking about. The Darwin system is one of the smaller systems in this class, for example larger steered array systems are installed in parliament houses in Wellington New Zealand, and Canberra and Sydney Australia.
The article was published in an industry magazine for general consumption. I'm not sure why you think it should have been written to satisfy your personal curiosities. I know about the Darwin system because I worked as an electroacoustic consultant for the company that designed it, although it was not specifically a project that I was involved in.
I did a google search and found a paper on the development of the type of loudspeaker used in the Darwin parliament. I have not yet read this paper, however it is available for your reading pleasure here:
Hybrid Line Arrays - A Viable Alternative
Hi Bill,
that is perfectly reasonable, and I have no complains about what you have said. I would do the same. However, I can't recommend this wire to anyone setting up a normal system. I'm not certain I would even when biamping. I have had to terminate it a few times, and while not a massive issue it is just more of a pain. The added expense of this product generally makes the decision given it offers no benefits to the normal speaker cable run.
Also the local arrangement is both a capacitor, and an antenna at the same time. There's a few ways energy can get to the lightbulb without mattering if the extremities are shorted or open, right when the switch is flipped.