Alex from Oz said:
Yes. I believe it is a system thing, and until proven otherwise LCR is what changes the behaviour of the system.
Also this means that any 'sound' or 'effect' that results is a property of the system and not a property of the cable itself, so you can say that "cables do not have a sound".
However there are those who believe that the cable itself does have a sound, or it produces a certain effect (usually a change in focus or sound stage) that they can hear. If this were the case it would be reasonable to expect that certain cables would eventually acquire a reputation based on what they sound like. And further more this sound or effect would follow the cable around in different systems. Even a body of anecdotal evidence to this effect would convince me that there something was going on.
If everyone has different opinions on the sound of a particular cable it is either in the their minds or we are back to LCR doing different things to different systems.
fredex said:
What were of interest to me in that test was that measuring into a resistive load show no differences between the input signal and what were seen on the load, using a real load changed everything even show differences on either side of the cable. Whether that 'small' differences are audible, that is the reason for this thread isn't it?
How many tests are done with real loads?
Alex from Oz said:
I agree, the redenation of cables 'measuring the same' or 'poorly designed equipment' has little to do with the fact that cables do make a difference in commercialy available systems.
The normal hi-fi listener (don't know if something like that exist 😀 ) don't walk around with a LCR meter and spectrum analyzer to buy equipment.
Another 'strange' observation I've made is that the more realistic a system sound, the easier it became to hear cable differences or is it differences that cables make.
I would disagree. A 1dB change in frequency response isn't a lot, but depending on where in the audio band, it can certainly be heard in ABX tests, despite the vagaries of loudspeakers and rooms. Take that number to 0.1dB and you'll get more agreement.
Andre Visser said:
The signal actually across the speaker terminals is the signal that moves the cones, not the signal across the length of the cable.
The thing I noticed is in Fig 6.9, the amplitude of the signals across the speaker is greater than that across the amp output. Odd? To me this suggests the plots on the right are showing speaker generated artifacts and not just the amp signal after it has travelled through the cable. The left plot show those same speaker generated signals attenuated by the cable and damped by the low output impedance of the amp, (the driving signal must also be in there)
Maybe somebody more experienced with these type of test signals would like to comment please ?
EDIT I meant Fig 6.8 full range speaker, but Fig 6.9 woofer shows the same effect.
scott wurcer said:
Um, wasn't that exactly what I've been proposing the past several days?
How many times can someone discuss how its not worth discussing anything in this goinn' nowhere thread.... and still keep coming back to post?
Fredex, surely the effects come from the speaker, thus explaining why it is larger on the speaker side, Point is you can now see differences measured on either side of the cable that were not the case with a resistive load. Now it is possible to see that different cables produce different results.
This put a big question on the normal 'measured into 8 Ohm' specifications of amplifiers.
This put a big question on the normal 'measured into 8 Ohm' specifications of amplifiers.
Steve Eddy said:
I need an editor.
I bring it up as an example only. It was not the usual AES suspects and ABX boxes trying to prove "all amplifies sound the same".
I think Mike is a sincere and intelligent guy most of the time. He has a recent fairly thoughtful blog entry covering the usual issues. He was willing to participate in that experiment which at least gives all this an air of ambiguity.
Maybe someone would like to do this very simple experiment
Mount different kinds of cables on each channel
Mount different kinds of cables on each channel
tinitus said:
I did something similar by mistake.I have packed a Philips JAN 12AX7WA tube(green letters) in the box of a Sylvania JAN 12AX7WA(again green letters)by mistake.A couple of weeks ago I have put this "pair" knowing it was a Sylvania pair.It took less than a minute to realize something strange was going on.Not so much a matter of frequency response etc...(they sound very similar anyway),but more a strange soundstage thing,mainly on the right side.I have removed the right tube to see if anything was wrong,and then I realized what I have done when packing them🙂
scott wurcer said:
Mmmm. Don't know any editors who are free at the moment. How 'bout just an Ed? I know an Ed who could use some work. He's not an editor but he's been an Ed for most of his life. That outta count for something I'd think.
You mean the Carver challenge?
Yes, it does.
And just to be clear, I wasn't defending Fremer on anything beyond his having been accused of having done things he hadn't done. I'd do that even if it were Curl. 😀
se
My apologies to all for opening a window to let some air in, but it was getting musty in here.
To contribute.
Here is why I liked the Cerwin test:
(Mostly a rehash of what Andre has already said.)
Here is what I did not like about the test report.
What I took away from that was not any definitive conclusions about cables, but that results can vary quite a bit depending on the cables and how they are used. System dependant. Notice that the report was light on the subjective side of things. That's probably a good idea.
To contribute.
Here is why I liked the Cerwin test:
(Mostly a rehash of what Andre has already said.)
- The test uses 3 different loads. A resistor, a speaker with a crossover and 1 without.
- The test uses an interest new signal and shows spectrum analysis. (more on that later)
- The second part uses different amplifiers.
- Results on different loads and with different amps show different results.
- Results on complex loads were different at different ends of the cable.
- The results on a simple resistive load seem to show little or no difference at either end of the cable.
- RFI was shown to have an effect.
- Romex seems to show the best results!
Here is what I did not like about the test report.
- No LCR measurements of the cables where shown. Thus we don't know anything about the "common" characteristics of the cables.
- It would have been nice to have at least a physical description of the 3 cables in the first test for reference.
- A 20Hz-20 KHz sweep on an LCR bridge would have been nice.
What I took away from that was not any definitive conclusions about cables, but that results can vary quite a bit depending on the cables and how they are used. System dependant. Notice that the report was light on the subjective side of things. That's probably a good idea.
multitone test signal
The test signal.
The signal used in the cable test at Cerwin labs is not the run of the mill test signal. It is a series of logarithmically spaced pure tones. This is meant to be closer to an actual musical signal than a steady state sine or swept sine, but easier to measure than noise.
The signal was not developed for testing cables; in fact it was developed to test compression drivers when the standard tests did not seem to correlate with subjective results. This is outlined in JAES document "Multitone Testing of Sound System Components—Some Results and Conclusions Part 2: Modeling and Application"
J. Audio Eng. Soc., Vol. 49, No.12, 2001 December
This signal tends to show a lot of distortion not easily seen in standard THD and IM tests.
The authors of the paper don’t claim that the signal is best of only way to test thing, quite the opposite. "…multitone application for the objective evaluation of sound quality is still far from achieving its potential."
But it does seem in interesting approach to testing and was used to good effect in the speaker cable test.
The test signal.
The signal used in the cable test at Cerwin labs is not the run of the mill test signal. It is a series of logarithmically spaced pure tones. This is meant to be closer to an actual musical signal than a steady state sine or swept sine, but easier to measure than noise.
The signal was not developed for testing cables; in fact it was developed to test compression drivers when the standard tests did not seem to correlate with subjective results. This is outlined in JAES document "Multitone Testing of Sound System Components—Some Results and Conclusions Part 2: Modeling and Application"
J. Audio Eng. Soc., Vol. 49, No.12, 2001 December
This signal tends to show a lot of distortion not easily seen in standard THD and IM tests.
The authors of the paper don’t claim that the signal is best of only way to test thing, quite the opposite. "…multitone application for the objective evaluation of sound quality is still far from achieving its potential."
But it does seem in interesting approach to testing and was used to good effect in the speaker cable test.
Re: multitone test signal
Thanks panomaniac, I was kicked many times before for complaining about single tone testing.
panomaniac said:
Thanks panomaniac, I was kicked many times before for complaining about single tone testing.
The multitone test signal is older than that. Actually its an extension of intermodulation testing, but the idea of using a whole farm of multiply unrelated frequencies is described in an AES paper on "Spectral Contamination" by Jensen in 1988 -- the paper can be obtained by request (but only by mail) from http://www.jensen-transformers.com/apps_wp.html. This was intended primarily for testing amplifiers, frequencies are arranged to minimize harmonics and IM products landing on top of each other.
(btw, if you listen to this multitone set, the idea of it being subjectively anything like music is way out there.... if you ever need to irritate someone with your stereo, this is the type of signal to use! Should anyone want to generate their own WAV files of these tone sets or any other multitone set, I can point you to some free software that will do it for you and play it through your soundcard).
Agreed that the Cerwinsky test could have gone further to determine if the cables were doing anything other than being linear networks. Putting a nonlinear source on one end and a (differently) nonlinear load on the other end of a network, why should the spectra on both ends agree?
__________
TBG1954 -- can you come up with a speaker cable that can be differentiated by ear from bog standard wire and that also be mailed back and forth for impedance cloning and further testing at both ends? I'm serious about trying to work this -- a good project to pursue this autumn.
(btw, if you listen to this multitone set, the idea of it being subjectively anything like music is way out there.... if you ever need to irritate someone with your stereo, this is the type of signal to use! Should anyone want to generate their own WAV files of these tone sets or any other multitone set, I can point you to some free software that will do it for you and play it through your soundcard).
Agreed that the Cerwinsky test could have gone further to determine if the cables were doing anything other than being linear networks. Putting a nonlinear source on one end and a (differently) nonlinear load on the other end of a network, why should the spectra on both ends agree?
__________
TBG1954 -- can you come up with a speaker cable that can be differentiated by ear from bog standard wire and that also be mailed back and forth for impedance cloning and further testing at both ends? I'm serious about trying to work this -- a good project to pursue this autumn.
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