How common is it for cheap store bought speaker cable (zip cord) to cause problem due to amp and speaker specs?
The characteristic impedance of a cable is the point where the capacitive energy and the inductive energy within the cable are equal. Zip is typically 120 to 150 ohms, depending on insulation and conductor spacing.
If I put a 100 ohm load on a 100 ohm RFZ cable, and want 1 ampere into the load from a DC supply, I use 100 volts. The energy stored in the wire due to current (the inductance of the wire) will equal the energy stored in the wire due to voltage (the capacitance of the wire).
If I put a 10 ohm load on the wire and push one ampere, it requires 10 volts. So the inductive energy stored in the wire is exactly the same as before, but the capacitive storage is much lower, by a factor of 100.
If you instead, vary the RFZ and keep the same load, and plot the inductive and capacitive energy storage vs line impedance, you see three things First, the inductive storage goes up as the line impedance increases. Second, the capacitive storage goes up as the line impedance decreases. Third, the summation of both energy storage mechanisms is a minimum when the line equals the load. There is a plot of this in my gallery here.
inductive and capacitive tradeoff with cable impedance and load - My Photo Gallery
When the cable RFZ matches the load, the cable stores less energy, so the amp spends more of it's effort on the speaker and less on the cable. IOW, more control over the load. This may be important when the load is a Nefariously Non Linear Load (NNLL), I intend on copyrighting that acronym. A voice coil with current moving in a gap is NOT a linear load at other frequencies when acceleration and velocity are involved.
I say may, because nobody has done the experiment I detailed yet on a speaker. It was only a few months ago that I realized that IMD testing of a speaker while varying the RFZ of the cable might just be able to see the smoking gun, and IMD is a test already well established. I detailed this to amirm back then, and gave him a few months to try the test on an Isolda.
No joy yet, no word. So, I bring it out for all to read and try.
jn
If I put a 100 ohm load on a 100 ohm RFZ cable, and want 1 ampere into the load from a DC supply, I use 100 volts. The energy stored in the wire due to current (the inductance of the wire) will equal the energy stored in the wire due to voltage (the capacitance of the wire).
If I put a 10 ohm load on the wire and push one ampere, it requires 10 volts. So the inductive energy stored in the wire is exactly the same as before, but the capacitive storage is much lower, by a factor of 100.
If you instead, vary the RFZ and keep the same load, and plot the inductive and capacitive energy storage vs line impedance, you see three things First, the inductive storage goes up as the line impedance increases. Second, the capacitive storage goes up as the line impedance decreases. Third, the summation of both energy storage mechanisms is a minimum when the line equals the load. There is a plot of this in my gallery here.
inductive and capacitive tradeoff with cable impedance and load - My Photo Gallery
When the cable RFZ matches the load, the cable stores less energy, so the amp spends more of it's effort on the speaker and less on the cable. IOW, more control over the load. This may be important when the load is a Nefariously Non Linear Load (NNLL), I intend on copyrighting that acronym. A voice coil with current moving in a gap is NOT a linear load at other frequencies when acceleration and velocity are involved.
I say may, because nobody has done the experiment I detailed yet on a speaker. It was only a few months ago that I realized that IMD testing of a speaker while varying the RFZ of the cable might just be able to see the smoking gun, and IMD is a test already well established. I detailed this to amirm back then, and gave him a few months to try the test on an Isolda.
No joy yet, no word. So, I bring it out for all to read and try.
jn
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So, someone copies Czinger 21C car shape, blood pressure monitor pump and charge that kind of money. I think you can build a kit sports car at that price.I would consider audible hum an audibly OBVIOUS flaw.
More to the point of the thread, if one device (amp/cable/speaker, and presuming a cable is so aberrant to make a couple dB difference - it would have to be a real monster ... ) sounds a little brighter than another, perhaps the response of one above 5kHz is one or two dB higher or lower than the other, it's an audible difference, but many people would have a hard time telling which one is flat and which one has a modified frequency response, even though this is easily measured.
I'm as hard-core an objectivist as anyone, but I have to wonder if you read his whole post. Some things you have to be deaf to not identify in a short hearing.
Well you know me (maybe) I'm always game for this sort of thing. I might be able to do something before I decamp to the mountains this summer.
Will we need any special amplifiers or speakers? We want to do the zip cord experiment? I own no fancy speaker cables at the moment, so testing those is out.
Wouldn't altered frequency response swamp just about anything else? If the cable causes amplifier oscillations that could easily be audible, but might be lumped in with frequency response differences. Amp instability is really a separate issue IMO.
There are sound outputs so different that they become easily audible and can definitely show in measurements. What he typically claims is based on subjective evaluation and then he hides when asked for details.
Not if frequency response was the same, or if it was intentionally being ignored. I can understand spoken words whether they are said at a high pitch, with a raspy sound, very low bass, etc. If I am listening for words then why would I care about frequency (except maybe for spoken Chinese which is pitch sensitive).
Pretty much.
Easily. Depends on spec., but you could build, say, four Westfield XIs for that with plenty of change or a choice of bigger jobs if you feel so inclined.
Nothing special. Just 4 lengths of zip. All 4 in parallel to one speaker will duplicate the Isolda inductance and RFZ, and when you split them, inductance and RFZ will rise dramatically.
Is your plan to use measurement equipment?
jn
Measurement equipment? What's that? Can't I just listen?
LOL, just kidding. I have just the basic sound card and FFT software, an L-C meter and that's about it. No longer own an oscilloscope. But certainly I can run FFT of dual tones on speaker cable.
How long should the cable be?
LOL, just kidding. I have just the basic sound card and FFT software, an L-C meter and that's about it. No longer own an oscilloscope. But certainly I can run FFT of dual tones on speaker cable.
How long should the cable be?
Long enough to get to the speaker.😀
maybe 20 feet?
If you want to listen, connect both speakers to one amplifier channel using 8 lengths of zip. Listen in sweet spot to verify all of the image is centered. Then split all the zip from one speaker, leave the other intact.
Listen to determine if all of the image content is still centered. You are not doing a head in vice thing, you are using your ears to see if any relative motion shows up between sounds that should be centered.
If part of the content shifts relative to other parts of the content.....
jn
maybe 20 feet?
If you want to listen, connect both speakers to one amplifier channel using 8 lengths of zip. Listen in sweet spot to verify all of the image is centered. Then split all the zip from one speaker, leave the other intact.
Listen to determine if all of the image content is still centered. You are not doing a head in vice thing, you are using your ears to see if any relative motion shows up between sounds that should be centered.
If part of the content shifts relative to other parts of the content.....
jn
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OK will try. 
The shifting image could simply be the result of different FR of the cables. That can be imitated with EQ, I've done.
The shifting image could simply be the result of different FR of the cables. That can be imitated with EQ, I've done.
Shift can be time or FR. But FR would mean drastic alteration, I believe the cable test envisioned cannot alter FR up to the human threshold.
If you wish to do both tests, do the listening test first, it needs 8 intact zips. then do the IMDD test using the unsplit zips.
jn
If you wish to do both tests, do the listening test first, it needs 8 intact zips. then do the IMDD test using the unsplit zips.
jn
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Sure I dodged your question. Why would you even ask it? Why did you not ask Hans the same question?
Your question and my answer are totally irrelevant in a thread about speaker cables.
FWIW, I don't do DAC's. I don't post about Dacs. I last bought a dac in 1998. I sold that same dac in 2000, and bought a one box player.
I did ask in the AK4499 thread if anyone was familiar with the new generation of Marantz sacd players and how they handle the quad dsd data.
Your quoted post leads me to believe you have me confused with someone else.
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