I never read any of his brickwall stuff.
David did some good work where he uses a third speaker as a reference to compare the placement of an image caused by two other speakers. In this way, the sweetspot and therefore head placement becomes less of an issue.
As I recall, in one of his papers he used that setup to show the variance between the pan sine law and position of the image as a function of frequency.
jn
Got a link to this 'proof', JC. Is it like the 'proof' you posted about zillion V/us slew?
When will you try Blowtorch on Ron's primitive test to show how it outperforms evil 4558?
Are you going to publish your results of the Hirata test on Blowtorch you conducted last Fri.? Surely they can't show anything you're ashamed to tell us?
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As I stated, the KISS principle is invoked...keep it simple, stupid.. (meaning me of course)...
edit: btw, you are correct, I normalized L and C...I hate that metric system...
I have not chosen that.
What I have chosen is an infinitely fast rise time step (relatively speaking, twas actually 350 pSec), and them watched how the load current rises vs time. When the load current rises to 80% in 10 uSec under a given line to load mismatch, yet rises to 100% in 350 pSec when line matches load and is consistent with the model, tis good enough.
The issue of capacitive reactance is only a concern at the amp's open loop unity gain frequency. If the cable appears too capacitive before that frequency is reached, it can reduce the phase margin below a nice number, toasting something..
jn
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Jneutron,
I happen to agree with most of what you are saying and feel that some of what is being said here is being taken out of context. Who is to say what realism in music is unless we are talking about simple acoustical instruments only? When we add in an electric guitar or any other electronic music what is the reference? It really comes down to the individual who is making the sound and the recording engineers interpretation of that sound and how he lays down the tracks. I am not saying that someone can't have an awful ear for sound and makes a lousy recording, but I think that the majority of trained engineers usually aren't tone deaf.
Now where this variation in impedance is supposed to be coming from that is allowing for a 10% difference in speaker to speaker values is a bit concerning to me. I do build speakers from scratch from the frame to the cone and have my own motor design and I am wondering where that much variation is coming from? I know I test more than a single unit when I am looking at the electrical responses of my devices and I have never seen that kind of variation. Something just doesn't add up to me. The difference between the moving mass from one device to another is at most a couple of mg. per device at most. And the machining tolerances are such that I doubt that you could measure more than a 0.001" difference between motor assemblies in tolerance. Now if we are talking about musical signal differences between two channels of recorded sound I can understand that, even in a so called mono signal. But 10 percentage difference between two identical devices under the identical test conditions I would be pretty upset myself. Perhaps I am reading to much into that statement, or perhaps that is the quality of speakers that you have tested. Perhaps this is the difference between using a paper cone and the composite material that I use in my cone production. Humidity and other factors do not change my cone material so that may be another factor in this discussion.
I happen to agree with most of what you are saying and feel that some of what is being said here is being taken out of context. Who is to say what realism in music is unless we are talking about simple acoustical instruments only? When we add in an electric guitar or any other electronic music what is the reference? It really comes down to the individual who is making the sound and the recording engineers interpretation of that sound and how he lays down the tracks. I am not saying that someone can't have an awful ear for sound and makes a lousy recording, but I think that the majority of trained engineers usually aren't tone deaf.
Now where this variation in impedance is supposed to be coming from that is allowing for a 10% difference in speaker to speaker values is a bit concerning to me. I do build speakers from scratch from the frame to the cone and have my own motor design and I am wondering where that much variation is coming from? I know I test more than a single unit when I am looking at the electrical responses of my devices and I have never seen that kind of variation. Something just doesn't add up to me. The difference between the moving mass from one device to another is at most a couple of mg. per device at most. And the machining tolerances are such that I doubt that you could measure more than a 0.001" difference between motor assemblies in tolerance. Now if we are talking about musical signal differences between two channels of recorded sound I can understand that, even in a so called mono signal. But 10 percentage difference between two identical devices under the identical test conditions I would be pretty upset myself. Perhaps I am reading to much into that statement, or perhaps that is the quality of speakers that you have tested. Perhaps this is the difference between using a paper cone and the composite material that I use in my cone production. Humidity and other factors do not change my cone material so that may be another factor in this discussion.
Sorry, the context is indeed confusing.
I was speaking of a driver's response to varying stimulus. To wit:
When a larger speaker is measured using a sine at 2Khz, for example, the Ls and Rs will be independent of the air mass the cone is involved with, and dependent mostly on the interaction of the magnetic flux of the VC and the magnetic circuit. More like holding the VC fixed within the gap so it cannot move.
Now, while measuring the Ls and RS of the system at 2Khz, move the VC within the gap at a 20 or 50 hz rate. You are now changing the gap flux in a strangely different way. What is the new 2Khz Ls and Rs?
I've pondered how to best measure this, but it would seem you are in a better position to do so. I do not have access to a speaker which has zero magnetic field, so any motion I impart to the measured VC will create a voltage which confounds my inductance meter.
Use two speakers bolted face to face. One complete with fully magnetized magnet, the second with an un-magnetized alinco or neo..keep the reluctance the same...
Measure the dummy inductance at 2Khz. Then drive the good speaker with a LF, 20 or 50, whatever, such that the dummy VC has motion within it's gap.
What does the dummy VC show for Ls/Rs?
edit: Actually, I'm sure any meter out there will be confounded by a time varying inductance and resistance, mine takes a few seconds to show 20 and 50 hz results..it would be better to toss a non inductive cvr in series with the dummy VC and look at the V/I response of the VC using an x/y scope setup.
jn
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Did i wrote that ? What allows-you to assert such things (with some kind of condescending attitude) ?
I'm interested about what you call *realism* when i produced records. And was payed for that ability and talent to create that kind of make believe. Dot.
When it is about reproduction, i want fidelity. Carbon copy. Not at all the same thing.
But of course, i'm blind, deaf and stupid and not enough experienced, after an all live dedicated to music and electronic for audio reproduction, to judge what is a good system, and what is not.
You are *the only one*. Congratulations.
Yes Jneutron, when i was talking about 0 ->150 Ohms impedance mountain curves, i was thinking of wire+ordinary enclosure, seen by the amp.
There seems to have developed a big discussion from the fact that I suggested that CAT6 or CAT6 screened cabled with all colors commoned & all whites commoned actually makes a pretty good speaker cable - especially for those on a tight budget.
I wonder of all the people who have commented how many have actually tried it ?
If you did, you might be pleasantly surprised.
It costs about $1 / meter and after a reasonable run in period they can sound pretty darn good.
I've no doubt that there are cables that may sound better out there but I would seriously doubt you will find anything that offers better value for money.
One day I will experiment to see what I can find that sounds better but I'm frightened to think how much I may have to pay.
p.s. CAT6 sounds better that CAT5 so I would not bother with CAT5
I wonder of all the people who have commented how many have actually tried it ?
If you did, you might be pleasantly surprised.
It costs about $1 / meter and after a reasonable run in period they can sound pretty darn good.
I've no doubt that there are cables that may sound better out there but I would seriously doubt you will find anything that offers better value for money.
One day I will experiment to see what I can find that sounds better but I'm frightened to think how much I may have to pay.
p.s. CAT6 sounds better that CAT5 so I would not bother with CAT5
REAL WORLD? I’m (pleasantly) surprised
http://www.klippel.de/uploads/media/Loudspeaker_Nonlinearities%E2%80%93Causes_Parameters_Symptoms_01.pdf
http://www.alcatel-lucent.com/bstj/vol14-1935/articles/bstj14-1-159.pdf
jn thanks for that:
As long as the coil moves and as long as cone acoustic load varies, impedance changes (add also back EMF).
So, for the first paragraph, you can not measure (edit: make any meaningful measurement of) inductance and resistance, unless you brake the coil.
For the second sentence of second paragraph, yes.
George
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Thanks for that Kindhornman.
One thing the audiophiles (i more and more hate their certitudes) doesn't understand, talking about bad recordings, it is how many of the records are done.
Near pure creation.
Musicians comes one after the others in a more and more little studio, and engineers try to create a realistic make believe the where all playing together in a big hall stage.
So they depend on the reproduction system of the studio they are working in, as it is their only reference.
Any defect of the studio listening chain (and they are a lot) will distort their work in an unexpected way.
Right now, i'm listening to a nice country and western record. Everything is very well except drums. The engineer had pushed-up the medium on the snare drum a little too high.
I'm sure the all drum kit sounded fantastic in the studio.
I'm sure too the studio's enclosures where a little too generous in basses with a lack of dynamic he tried to compensate.
Now, chose between two systems in a shop, the one witch will reproduce those drums without this defect: you had chosen a bad system.
Who talk about "realism" ?
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The point is this.
I have ABSOLUTELY NO PROBLEM with Golden Pinnae stuff including Unobtainium hand carved by Virgins on a product where there are few cost constraints PROVIDED ...
... the Golden Pinnae stuff PERFORMS AT LEAST AS WELL as cheapo stuff.
JC will now provide 'proof' that Blowtorch has exemplary performance on the Hirata tests he did last Fri.
Then he will show that Blowtorch beats 4558 on Ron Quan's supa dupa test. Some gurus have said these tests are really important.
Are you sure he was doing any Hirata test last Friday? My understanding was he was provoking others to make the test as their homework
Possibly.
Indeed. I said nothing about adding anything to the signal.
I didn't say and I didn't mean "ultimate soundstage or performance".
I spoke only of the sense of realism of the music.
I know that not many people are interested in it, I do.
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