How are we using the term "sound" in this instance? Do we mean as in possibly placebo (see above), or a real physical difference?
Is the current thinking that 'no cable is the best cable'? Or that a cable "can improve the sound"?
So, they want to create a more capacitive cable because capacitance (C) varies less than inductance (L)? The only way to reach -90.000 degrees is with a purely capacitive cable, i.e. no resistance and no inductance, or some network that achieves that goal. Note that is not the goal of most transmission lines; an ideal lossless line has zero R, infinite G, and sqrt(L/C) such that the ratio of L and C determine the desired cable impedance. Optimum power transfer occurs when the line’s impedance matches the load.First, to reiterate, they seem to be concerned more about inductance than capacitance, though the patents are apparently adjusting both: The net effect of parasitic resistance normally seen in audio cables is the loss of one-half of one degree, to one and one-half degrees off the capacitance phase angle. Typical values for parasitic resistances (Rp) are usually on the order of several Mohms, though these too can be frequency dependent and vary widely. However, -89.5° is a typical non-ideal capacitance phase-angle value for an audio cable when measured at audio frequencies. Therefore, the capacitive component of high-quality audio cable normally does not vary far from the ideal within the audio frequency range. This is not the case with the inductive component, as we will see next.
ack said:Second, they calculate power factors at 100Hz and at 20kHz, which are respectively: PF = cos(5.00) = 0.996 [ack: approaching 1 - VERY poor] and PF = cos(82.199) = 0.136
Third, to answer opus's question on the test equipment they used, the white paper refers to a Hewlett-Packard 4284A Precision LC R analyzer. Under computer control, measurements were taken from 20Hz to 20kHz, with resolutions as high as 2000 points. The oscillator output level was set to 1 volt. From these measurements, the power factor was calculated and plotted. A test and measurement note: Measuring a multi-gauge audio cable is more complicated than measuring a zip-cord-type cable. In a multi-gauge cable, each gauge conductor must be measured separately and the data re-assembled mathematically. They then show plots of various cables which I won't repeat here, but it's clear that, if true, various cables would emphasize and de-emphasize certain frequencies based on the alleged power factor measurements at those frequencies. I see no further details on the tests themselves.
Fourth, on Don's question: am I talking about interconnects or speaker cables... The papers don't make the distinction, but I did replace one at a time. After replacing the interconnects I noticed a slight drop in the bass and nothing else, but it turned out the cables were not broken in. The situation with the speaker cables was more dramatic, and once they also broke in, switching between interconnects revealed a slight veiling with the old ones. Based on the fact that the Spectral amps need a lot more input current to be driven properly than most others (100mA for rated power), I _surmised_ earlier in this thread that perhaps MIT's claims are perhaps more relevant where there is plenty of voltage and current, i.e. speaker cables (and in my special case, also interconnects but to a lesser degree).
Finally, having said that, here's how I summarized to others my listening observations (and am including their response as well) of the new Matrix cables vs the older Spectral/MIT cables:
1) Very dynamic - this was the most surprising trait, as a cable is least expected to enable (or suppress) dynamics.
2) Higher resolution than the old Spectral cables - exceptionally well-defined soundstage; wow
3) Proper amplitude with every note - makes the old ones sound like they are chopping off the amplitude
4) Tight, extended, non-hifi, articulate and properly positioned in the soundstage bass - this is impressive, especially with organ, where each individual bass note has all the pitch definition I would expect to hear; but also with properly recorded bass drums
5) All of the above render an exceptional truth of timbre - simply stunning with electrostatics
Response: I could not have articulated that better, well said. I agree with each point. Your comments regarding dynamics especially stood out. I remember talking with a friend about the bass...where was it before!? It seems all the energy was there, it had to be. Somehow the cables focus that energy and it translates into significantly more/better extension.
I would love for anyone to be able to explain these observations scientifically, though I am also willing to accept that perhaps the network components' quality in the boxes of the old cables is simply lesser...
(...) Hmmm… Pretty subjective impressions and I am not quite sure what to do with them. The MIT white paper applies T-line theory at audio and claims the low inductance of most cables is a problem which they have solved with their special construction techniques. Adding series inductance will tend to emphasize bass and reduce highs, though how much change there is due to a cable is hard to say. The goal appears to be to eliminate loss, which can be achieved by reducing the resistance, and maximizing real (“active”) power through matching networks. Given the fairly fixed impedance at audio of most low-level sources and loads, and widely variant impedance of most loudspeakers, they would have to design the network to match the source and load to achieve maximum power transfer in the system. However, by using a combination of passive components, they could certainly emphasize (or e-emphasize) different frequencies that would provide a pleasing sonic result.
Here is a nice paper with simulations and actual measurements of Monster cables and generic: http://dspace.mit.edu/bitstream/handle/1721.1/46225/41567257.pdf
It has interesting measurements like THD of cables! Never thought about doing that.
I was really interested in the test set-up, not only the signal source. But already this is starting to look odd. The HP you cite is a component tester - that means it tests single port networks only. A cable is a two port network - to test a cable they'd have needed a network analyser.Third, to answer opus's question on the test equipment they used, the white paper refers to a Hewlett-Packard 4284A Precision LC R analyzer. Under computer control, measurements were taken from 20Hz to 20kHz, with resolutions as high as 2000 points.
The oscillator output level was set to 1 volt. From these measurements, the power factor was calculated and plotted. A test and measurement note: Measuring a multi-gauge audio cable is more complicated than measuring a zip-cord-type cable. In a multi-gauge cable, each gauge conductor must be measured separately and the data re-assembled mathematically.
They then show plots of various cables which I won't repeat here, but it's clear that, if true, various cables would emphasize and de-emphasize certain frequencies based on the alleged power factor measurements at those frequencies. I see no further details on the tests themselves.
Here is a nice paper with simulations and actual measurements of Monster cables and generic: http://dspace.mit.edu/bitstream/handle/1721.1/46225/41567257.pdf
Here is a nice paper with simulations and actual measurements of Monster cables and generic: http://dspace.mit.edu/bitstream/handle/1721.1/46225/41567257.pdf
It has interesting measurements like THD of cables! Never thought about doing that.
Apt holman preamp specs are easily located. http://kenrockwell.com/audio/apt/holman-preamplifier.htm
Begins with the assumption that the high end in general and and cables in particular are a rip off. Then sets out to prove it. Ignores anything contradictory.
I didn't post the paper for its conclusions. I post it since it has a lot of measurements in there.
I post it since questions were asked about frequency response of cables. He did that test plus some.The measurements are fine, made with decent kit. Just so happens though that they're the wrong ones if we'd like to explore why cables sound different.
I don't think he was lazy at all. He ran tons more tests than any other report like it that I have seen. He tested dozen plus cables. He is testing using the same analysis that we use for audio equipment in general: frequency response, phase, noise, THD, etc.So why did Mr Cooper decide to make those particular measurements and not others? I have some ideas myself but they pretty much boil down to intellectual laziness. What do others think?
...as far as cables sounding different...those that don't believe need a hearing test, given respectable gear and setup..
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