You can't measure a simple wire? What hope is there for you then? How's that for irony?
Flat frequency response would seem to be a great way to know huh?
No obscure phase changes.
Can you not tell when the bass or midrange or treble is depressed or elevated in a speaker? Same rules apply.
Now go out and find me a cable that doesn't sound neutral and measure it.
Come back and talk about irony when you can make your point objectively.
If you use a lot of this...............then everything will sound different after a while.
More irony .....
Your the one with the put up , not me, so how are you going to determine how a cable sound without golden ears , explain ....
What you are proposing will simply determine the time of flight out and back, and the reflection coefficients. Both of these are easily calculated, and I'm sure that's exactly what you would end up measuring.
The concept is basically determining how fast the load will be at the current which the amplifier is attempting to produce. If you have a 10 ohm load with a 100 ohm cable for example, and you have the amp step 100 volts, how long will it take for the load to achieve 10 amperes?
For ZL =10, ZS=100
The reflection coefficient is ZL-ZS / ZL+ZS. (10 - 100)/(110). -90/110 = -.8181
The transmission coefficient is 2 ZL / ZL+ZS.
2 * (10) /110. 20/110 = .1818
Let's assume 50 nanosecond long line.
at 50 nano, the leading edge hits, the load voltage rises to 18.18 volts and 1.818 amperes, and -81.81 volts reflects toward the source.
at 100 nano, the entire line has a voltage of 100 - 81.8, or 18.18 volts, exactly what the load sees..so at time t=100 nano, a CVR at the source will see 1.818 amperes.
By using the cvr current, you can see exactly how fast the load is settling to final value, but remember that it will be exactly one transit time delayed.
At 100 nano, the source will reflect the 81 volts towards the load, and the line will again be 100 volts...that 81 will hit the load at 150, and the same transmission and reflection coefficients will apply, so every 100 nano's, the load current will rise an additional 18% of the difference between the final voltage and where it stands.
Also, you don't need a particularly fast step rise, although I'd probably use 250 picoseconds...you can use anything like ten or 20 nano if you want to see clearly, or half a micro if you're not nuts like me.
Once you have a setup running with a simple zip cord, replace the load with anything from 1 to 1000 ohms. If you've done it right, you will find that when the resistor matches the line, the settling time will be a direct copy of the risetime of the step.
sigh...I hope I typed correctly...
edit. to answer your question, the settling time is really a measure of how quickly the line "fills up" with energy (load<line). Until the line has "filled", the load current will not be what the source wanted.
You can use the exact same setup with sine output, and the cvr will measure the time difference between the stimulus and the load current. And, as a check, when you match the termination, there should be almost zero delay between the current and the voltage at the source.
jn
Last edited:
Achieving this has nothing to do with the source material, or the speaker type, it's about the integrity of the system as a whole. Meaning, the level of certain types of distortion are below significant audibility. The vast majority of systems, irrespective of spec's or cost, don't address this sufficiently, hence never approach the required level of audible quality.
It's not about the size, it's about the quality! This means that the images of the musical elements don't become bigger, rather they become clearer, more sharply defined - they appear absolutely rock solid as "things" in the soundscape - another simple analogy, you look at a sports crowd on mediocre TV, it's just a blur of colour; on a professional quality monitor, each face becomes discernable, you can see the movement of the head, the emotion of the person is apparent, just watching the behaviour of a single individual in that huge crowd now becomes "interesting" ...
Hahhh! I've been aiming to do that for years, it's the long term goal - hard yakka, unfortunately.build it and show them frank, go ahead ........
The simple truth is the slightest interference effects, anomalies in the environment, can be enough to pull the quality down from the required plateau. All the aspects that matter have to be made extremely robust, to be engineered such that they are able to shrug off adverse influences in all typical environments - and this is very frustrating, because a lot of the time you don't really understand what the true, and full, nature of the interactions are, you're stumbling around in the dark.
The end goal is a portable system, that can be plunked down anywhere, and will achieve what I talk of, every time. Still not there yet, but hopefully one day ...
Sigh..what a blasé statement..
I'm an engineer...If I want blasé, I'll try to aquire a personality..It is important to attack ALL aspects of the system. I do what I can.
We certainly do not disagree, but I focus on some aspects that are insufficiently controlled.
jn
Stepped on???
Scott, I have a block of aluminum 6 inches by 8 inches by 4, maybe you can hog it out??
jn
Its saves me worrying about cables
Why worry about cables? Unless you have no slightest idea on how to make a good sounding system.
The big mess with audio is they don't know what to achieve. The consequence of the mistake is then they will try to adjust anything in the chain to "balance" the sound, to adjust to their taste.
As long as you don't choose the cheapest (that doesn't make sense) you should be fine. My worst experience was with an old movie projector. It came with Teflon insulated coaxial. It sounded very fatiguing. Tried to break it in but didn't change and I gave it up.
Of course it's "blasé", but it's still the root cause of most system "problems" - and this is ignored, well, about 99% of the time. If I hear an expensive system sounding "dreadful" my mind starts to tick off immediately, about half a dozen things that "need to be sorted out" - so that at least decent music can be listened to ...Sigh..what a blasé statement..
It is important to attack ALL aspects of the system. I do what I can.
So, the 'fact' bears repeating, again and again ...
You're aware of the weakest link "theory", aren't you? Check speaker, it is more than just insufficiently controlled. Fix it and everything else is fine
Can you elaborate? If it is fixable I will try to find the cable. It was quite long for a movie cable (it should be in one of those big boxes)
Basically, test if stabilising the cable, or altering the environment it's in alters the audible behaviour. Say, try using a length, where in one situation it's free to flop around, and a second where you go to great lengths to damp, lock down the cable material so it can't move, or freely vibrate, at all.
People here will start chuckling, but try comparing when the cable material is resting on other materials along its length, as compared with hanging in the air. I know, this goes against the sense of the first test - I never said this was easy! If you try this, be 100% scrupulous in how you go about it - near enough is not good enough!!
Try changing the humidity around the cable, could do something silly like wrapping wet material around it along its length - which I have never done - but doing something extreme like this may 'prove', or indicate something, either way ...
People here will start chuckling, but try comparing when the cable material is resting on other materials along its length, as compared with hanging in the air. I know, this goes against the sense of the first test - I never said this was easy! If you try this, be 100% scrupulous in how you go about it - near enough is not good enough!!
Try changing the humidity around the cable, could do something silly like wrapping wet material around it along its length - which I have never done - but doing something extreme like this may 'prove', or indicate something, either way ...
One would expect with sensitive enough equipment difference in capacitance with regards to the floor could be measured.
You would have to try it on a suspended wooden floor as well as a basement floor, or other floor in direct contact with the ground.
The capacitive coupling should be greater in the second scenario.
This is were a shielded cable such as RG-8 mentioned a few pages back in that article should do well.
You would have to try it on a suspended wooden floor as well as a basement floor, or other floor in direct contact with the ground.
The capacitive coupling should be greater in the second scenario.
This is were a shielded cable such as RG-8 mentioned a few pages back in that article should do well.
Stepped on???
Scott, I have a block of aluminum 6 inches by 8 inches by 4, maybe you can hog it out??
jn
To clarify the "case" was made out of and old cut and bent ST-70 cage. It folded crushing everything flat. The parts have all been saved.
Paul join the fray, must have heard about JC's wilson step up ........
Building a new Music Room Part 7 - YouTube
I wonder if Paul's using any AD745's...?
Doubt it. Ultimate irony Paul's speakers were part of the best setup I ever heard, the one I mentioned as the only time the bass was right. Old school technology to boot. The system was all big $$ valve with a Goldmund reference and precious Koetsu cart. The guy listened to nothing but LSC's and Living Presence both in complete collections up to 5 deep on many. I guess I got out just enough.
One night he said, "Is Harry Pearson losing his mind" as he put on "Autobahn".
Hmmm... I prefer to buy a new one or use what I have on hand which work fine out of the box without any special treatment.
And that's the "problem" with me. Many people try to find out technical explanation why cables sound different. I don't have interest to find out. For me technical skill is required to get to the good sound. Once the good sound can be achieved, I don't care with the Physics. If I try to find out, may be I can do better at that. But why? What for?
Interestingly enough, I heard the Australian equivalent of that system nearly 30 years ago, about the only difference was that the electronics were all Audio Research. The vinyl cuts were very impressive, certainly demonstrated what the format was capable of.
Unfortunately the CD side of it used the "discard what may be unpleasant" creed, so half of the music on my test disks completely vanished when they were played ...
Last edited:
- Status
- Not open for further replies.