Here in Canada the engineer at CBC has a cable analyser.
He performed severall tests on 12$ shielded cable and the 40 $
ones . There were no difference.
That puts and end to your inquiry.
....................................................🙂
He performed severall tests on 12$ shielded cable and the 40 $
ones . There were no difference.
That puts and end to your inquiry.
....................................................🙂
I would be interested in what the brand and model of the cable analyzer is, and probably later how the test was setup, what test signals were used, etc. Some people come up with measurable differences, some don't.CONVERGENCE said:
Being a DIY is great. If you want to experiment with cable, you can. I just got 50ft of 99.999 solid core silver wire in Teflon for RC As. I'd be extremely surprised if it did make a slightest difference in my system. As a mater of fact, I will try it in 5 different setups and let you know.
I play with cables for the looks.
Good connectors are important. Gold plaiting is important and a good dielectric can make a difference. But wire itself? I don't believe so.
Look at it this way. The demand for the better products is there. A wealthy shmak, purchasing a stereo system and wishing to impress his friends will ask for the best. Manufacturers are simply giving him what he wants.
It is a shame, then a young kid with $10an hour job is sold on this by an *** of a salesman in audio boutique. I was almost that kid except something stopped me. I was also told that the most important element in the stereo system is the CD transport.
Like anything else. Do your research.
I play with cables for the looks.
Good connectors are important. Gold plaiting is important and a good dielectric can make a difference. But wire itself? I don't believe so.
Look at it this way. The demand for the better products is there. A wealthy shmak, purchasing a stereo system and wishing to impress his friends will ask for the best. Manufacturers are simply giving him what he wants.
It is a shame, then a young kid with $10an hour job is sold on this by an *** of a salesman in audio boutique. I was almost that kid except something stopped me. I was also told that the most important element in the stereo system is the CD transport.
Like anything else. Do your research.
CONVERGENCE said:
I saw that episode of Marketplace. While I would never drop $240 on a Monster HDMI cable (15 foot for $25 at NCIX for me) that test looked poorly constructed. I swear the engineer said the source was DVD (for HDMI?) and the only thing tested was data integrity.
I've had line level interconnects make a difference, but I believe it was for obvious reasons related to the output impedance of the preamp, the RLC values of the interconnect, and the input characteristics of the amp. Absolutely nothing magic or inexplicable, and no need to invoke skin effect, single crystal metals, or any other snake oil explanations. Just slight changes in frequency response. The difference was minor. Interestingly, since I went to a tri-amped active crossover system, low level and high level interconnects seem to make no difference what-so-ever. Nor do amplifiers. Narrowing the bandwidth of any component is a good thing.
soongsc said:
I'm afraid not. Signals travel down typical co-axial cables at about two-thirds the speed of light and a mismatched cable will cause a reflection. However, audio cables are not transmission lines unless they become very long. Consider, one degree at 20kHz is 139ns, so at two thirds the speed of light you would need a cable 28 metres long to achieve a delay equivalent to one degree at 20kHz. Leaving aside whether one degree at 20kHz is even audible, domestic cables aren't 28m long.
I'm afraid not. Any time energy cannot be fully transferred, it will be reflected. Where else would you propose it to go?EC8010 said:
The point is not whether it will be reflected, it is that you won't be able to distinguish between the original and any reflection.
I'm sure some can, some can't. The last time I did measurements of speaker wiring with with amp driving speaker, and the hamonics are altered with different cable. This is the same thing that happens when measuring capacitors. I'm sure if a difference can be heard, there should be some way to relate measurements with what is hear.
Believe what you will, but transmission line theory is inappropriate to audio frequencies travelling down cables of domestic lengths. If you can hear a change by changing cables it is not due to reflections - look elsewhere for your explanation. The most likely reasons are:
Amplifier to loudspeaker:
Cable series inductance or shunt capacitance causing a change in the stability of marginally stable amplifier.
Cable (aerial) picking up RFI and injecting it into feedback loop of amplifier to be demodulated by input stage.
Cable increasing source resistance as seen by loudspeaker (and crossover, if any).
Line level to amplifier:
Capacitance loading source.
Shield resistance affecting hum (due to hum loop).
Shield affecting hum (electrostatic hum).
Twisted pair reducing hum (electromagnetic hum).
MC transformer to RIAA stage:
Capacitance upsetting transformer secondary (always put the transformer in the RIAA stage)..
Cartridge to RIAA stage:
Capacitance loading source (MM cartridges).
Shield resistance affecting hum (due to hum loop).
Shield affecting hum (electrostatic hum).
Twisted pair reducing hum (electromagnetic hum).
Amplifier to loudspeaker:
Cable series inductance or shunt capacitance causing a change in the stability of marginally stable amplifier.
Cable (aerial) picking up RFI and injecting it into feedback loop of amplifier to be demodulated by input stage.
Cable increasing source resistance as seen by loudspeaker (and crossover, if any).
Line level to amplifier:
Capacitance loading source.
Shield resistance affecting hum (due to hum loop).
Shield affecting hum (electrostatic hum).
Twisted pair reducing hum (electromagnetic hum).
MC transformer to RIAA stage:
Capacitance upsetting transformer secondary (always put the transformer in the RIAA stage)..
Cartridge to RIAA stage:
Capacitance loading source (MM cartridges).
Shield resistance affecting hum (due to hum loop).
Shield affecting hum (electrostatic hum).
Twisted pair reducing hum (electromagnetic hum).
All you have mentioned seem related with impedance characteristics, which relate with how energy is transferred and reflected back into effecting the performance of the driving electronics.
EC8010 said:
The invoking of the prop velocity of a cable is only appropriate for first pass energy. First pass energy is only the energy that can travel at that speed.
For example, if one uses a 100 ohm cable to drive an 8 ohm speaker, and uses say, 100 volts as the step function (for cleanliness of argument), that front will indeed travel at the prop velocity of the line...However, at the load, there is only 1 ampere available to the load. So after say, 139 nanoseconds, the load will have 8 volts impressed upon it, the difference of -92 volts will be reflected back to the source(reflection at a lower impedance inverts the signal). When the +92 volts (reflection at the zero impedance source) returns to the load, it hits the load, inverts again, an additional 7 and change volts appears at the load, and a -85 volt signal goes towards the source.. Eventually, it will settle down to 100 volts at the load, and the current will eventually settle down to 100/8 amperes, 12.5..And it will take approximately twice the lumped inductance/load resistance LR time constant to reach 63%.
Note that each return signal takes 139 times 2, or 278 nanoseconds. 10 transits for example, is almost 3 uSec. The amount of settling that has occurred in 10 transits is a strong function of the impedance mismatch. That is because you are trying to force the load's current demand upon the line, and that current is (for the stated example) 12.5 times that of the current that the line will transmit at it's characteristic velocity of propagation.
EC8010 said:
Well, almost..
Note that the previous discussion concerns a mismatched line/load. There is a cusp in the response plot, that is at equality. There, the 90% point is reached at exactly 139 nanoseconds.
Cheers, John
soongsc said:
Here is the sight were you can find the CBC special and view the video program.
http://www.cbc.ca/marketplace/2008/02/20/packing_the_deal/
............................................
Howdy Folks, I guess it's my turn to tiptoe through the minefield! That's ok, Im wearing my nomex suit so here goes....... Electrons don't care how much you paid for your speaker cables. All they care about is,capacitance, resistance and inductance. Boutique cables with their artisan woven, individually insulated, conductors act as capacitors, A.K.A tone controls! This is not getting an unsullied signal from the amplifier to the speakers. In addition, the added capacitence can cause some amplifiers to go unstable. Adcom fet amps are notorious in this regard. Although I love my GFA5500 to death, it would not be my first choice to drive an electrostatic speaker fed by boutique cables! Esoteric effects such as skin effect occur so high up in the radiation spectrum as to be inconsequential in audible terms. Solid core Bell wire, mechanical properties excluded, would seem to be the ideal cable from an electrical standpoint. Bottom line.........If you want tone controls, get a preamp with tone controls and save the money! PS. I'm using "El Cheapo" Monster cable but plan to try solid core in the near future.
I'm not famliar with HDMI, but if these are digital signals, as long as the bits are transferred correctly, the quality the depends on how the receiving end processes the data. This is totally different from analog signal transmission.CONVERGENCE said:
John, where do we find an audio signal or an audio amplifier that can do a 100 volt step function in 139 nanoseconds?
soongsc, HDMI is all digital, four differentially signalled channels if I'm not mistaken.
Speedskater, John's example was a hypothetical example of a 100V step function with zero rise time. 139ns was the propagation delay of the signal from one end of the cable to the other. Basically the speaker voltage steps to 8 volts when the step arrives, not 100. Then 278ns later it steps from 8 to ~15, then 278ns later it steps again, each step getting smaller, until after infitely long it reaches 100.
Speedskater, John's example was a hypothetical example of a 100V step function with zero rise time. 139ns was the propagation delay of the signal from one end of the cable to the other. Basically the speaker voltage steps to 8 volts when the step arrives, not 100. Then 278ns later it steps from 8 to ~15, then 278ns later it steps again, each step getting smaller, until after infitely long it reaches 100.
Speedskater said:
Why would we want to?
The rise time of the test signal has nothing to do with how the cable will react. The point is, there will be reflections regardless of the rise time, and those reflections eventually die down, acheiving the steady state conditions that the source is forcing on the load.
If you used a signal which had a millisecond rise time, this 139 nanosecond delay cable would settle to to under a percent or so of the actual signal three orders of magnitude faster than the waveform.. Not too many instruments are capable of seeing a clear microsecond delay on a millisecond waveform..
Personally, I'd use a mercury wetted reed to make the 100 volt step, and it has a rise time of 350 picoseconds.
My point is, in this example, using the prop velocity by itself makes one assume that the signal will be fully "arrived" at the load in 139 nanoseconds, but in actuality, it will fully arrive (to 1% or so) in a significant multiple of that transit time. Only the leading edge of the signal will make it to the load in 139 nanoseconds, and the energy in that fast transport will be entirely dependent on the cable impedance and the load impedance. For the 100 volt, 100 ohm Z, 8 ohm load example, we sent 100 watts down the line, and 8 watts showed up at 139 nano.
268 nano later, another 7.36 showed up.
Whereas, if the load was 100 ohms, then 100 watts would hit the load at 139 nano.
It's real easy to make an excel ss to see how the risetime is altered by the impedance ratio.
Cheers, John
ps..I type too slow....hey fizzard...
I've found exactly the same thing.Conrad Hoffman said:
Expensive cables are for deluded fools who prove Barnum's Law. Note most of these are non-DIYers who usually at least try to get away from the BS a little better than the Agon boutique shoppers.
EC8010's response in post 850 is correct. /discussion.
The effect of cables is dependant on the system that it is used on. If used on a system designed to be revealing, it will have quite a large influence on the sound quality.
Further it will depend on the type of music that you listen to, according to me it is worthwhile to experiment with better cable if you prefer acoustical instruments, even voice.
Finally it depends on what you expect from the system, if your aim is to retrieve every possible detail from the recording and want it to sound accurate, then the whole system has to be good, including cables.
André
Further it will depend on the type of music that you listen to, according to me it is worthwhile to experiment with better cable if you prefer acoustical instruments, even voice.
Finally it depends on what you expect from the system, if your aim is to retrieve every possible detail from the recording and want it to sound accurate, then the whole system has to be good, including cables.
André
- Status
- Not open for further replies.