| lineup |
| quote: | The idea that "so-called simple perceptions are anything but simple"
was dramatically illustrated by magician and inventor Jerry Andrus.
Based on the concept that perceptions are easily altered by expectations,
Andrus has created many optical illusions and magic tricks that fool the observer.
"Each person paints their picture of reality
with a brush dipped in the pigments of the past," he said.
With a simple demonstration using what appeared to be a deck of cards
(but which he revealed was really a thick piece of Plexiglas),
Andrus illustrated how the assumptions we make about reality,
based on years of ordinary, day-to-day experiences,
often lead us to "see" things that do not exist.
In another example of playing with expectations,
Andrus removed the glasses he had been wearing since the beginning of his talk,
admitting: "They contain no glass. I wear contacts."
Accompanied by abundant laughter and applause,
Andrus continued his performance with a number of large optical illusions
that he manipulated to produce further false perceptions. |
Most things that I hear and see are no doubt for real.
And everybody else would clearly hear and see the same thing.
But some things I hear and see,
especially at the limit at which my eyes can see and my ears can hear and beyond that,
may only be a perception, that does not exist for real.
And this perception may be real for me only.
Nobody else would see or hear the same.
A perception is not simply a signal from my ears or my eyes.
It is a product of signals from all my senses and my own mind.
I thought I heard you saying something ....
Sounds make up a thought.
Can a thought make up a sound? |
|
|
| phase_accurate |
I have never tried bi-wiring myself as I am running active so I can't comment on its effectivenes from a SUBJECTIVE point of view.
There is however an OBJECTIVE mechanism in place which is not even that complicated to understand (it is much simpler as jneutrons explanation) and I don't know about its quantitative properties either. But let's have a look how it works:
Even tough very small - the cable presents a series resistance to the speaker and forming a voltage divider with said speaker (it is actually more than just a series resistance but for this explanation this view suffices). If the load were completely linear and thus the current flowing through it proportional to the voltage across it - nothing special would happen.
But a loudspeaker ISN'T alinear load. A driver's impedance varies with escursion and thus we now get a nonlinearly-signal-dependant voltage-divider which causes IMD.
If every driver has an own cable and therefore its own unanvoidable voltage-divider there would be less nonlinear interaction. As already mentioned I don't know the quantities and there will be situations where it doesn't have any merit at all. One example would be tube amps with low DF where the output series resistance is higher than the cable resistance.
One article dealing with that (from someone who definitely is an objectivist):
http://www.resolutionmag.com/pdfs/DRAGONS/SPEAKE~1.PDF
Regards
Charles |
|
|
| Christer |
John,
I cannot see why the instantaneous power should be of much interest. What matters in most cases are voltages and currents. Voltages and currents superimpose, power doesn't (as you clearly demonstrated). however, the power is just a consequence of voltage and current. Add all voltages, add all currents, multiply and you get the power. The power is a causal effect from voltage and current (at least as far as I know), so whatever strange frequency components you get in the power function won't matter, since it won't affect the voltage and current (as long as we don't consider second-order effect like temperature dependency of resistance etc.).
I do buy Charles' explanation though. That one seems reasonable. |
|
|
| jneutron |
| quote: | Originally posted by poobah
Yeah,
Your frying secret gluons and cr$p right? |
No, you are confusing my work environment with my own personal desires.
While the quark/gluon stuff coming out of the collider here is really interesting, that is not where my interests lie.
Cheers, John |
|
|
| jneutron |
| quote: | Originally posted by phase_accurate
I have never tried bi-wiring myself as I am running active so I can't comment on its effectivenes from a SUBJECTIVE point of view.
There is however an OBJECTIVE mechanism in place which is not even that complicated to understand (it is much simpler as jneutrons explanation) and I don't know about its quantitative properties either. But let's have a look how it works:
Even tough very small - the cable presents a series resistance to the speaker and forming a voltage divider with said speaker (it is actually more than just a series resistance but for this explanation this view suffices). If the load were completely linear and thus the current flowing through it proportional to the voltage across it - nothing special would happen.
But a loudspeaker ISN'T alinear load. A driver's impedance varies with escursion and thus we now get a nonlinearly-signal-dependant voltage-divider which causes IMD.
If every driver has an own cable and therefore its own unanvoidable voltage-divider there would be less nonlinear interaction. As already mentioned I don't know the quantities and there will be situations where it doesn't have any merit at all. One example would be tube amps with low DF where the output series resistance is higher than the cable resistance.
Regards
Charles |
The complexities of the drivers and the complexities of four quadrant operation cause the math to become intractible. This is why I chose a sine plus a dc component for illustration, that is more easily understood. (KISS principal I find best for myself, as manipulation of more than 3 or 4 active variables starts getting complicated.)
My analysis was done using purely linear components for just that reason. There are far more issues involved when speakers and human hearing are added..that eventually, but not now. As you can see from the responses of others, the ramifications of even this simple analysis are not understood well.
Cheers, John |
|
|
| SY |
Charles, that's a fine and sensible article. Thanks for the link. There's a few things he didn't cover (e.g., wire as tone control), but the basics are there and well-explained.
I hate the terms "objectivist" and "subjectivist." No one can seem to define them in a useful and consistent way; getting someone to define what they mean by these is as difficult and rewarding as trying to staplegun some goat liver to sheetrock. When I hear "objectivist", I think, "Ayn Rand." |
|
|
| jneutron |
| quote: | Originally posted by Christer
John,
I cannot see why the instantaneous power should be of much interest. What matters in most cases are voltages and currents. Voltages and currents superimpose, power doesn't (as you clearly demonstrated). however, the power is just a consequence of voltage and current. Add all voltages, add all currents, multiply and you get the power. The power is a causal effect from voltage and current (at least as far as I know), so whatever strange frequency components you get in the power function won't matter, since it won't affect the voltage and current (as long as we don't consider second-order effect like temperature dependency of resistance etc.). |
Any power that is dissipated within the wire is power that is not delivered to the load. That is what matters.
There is nothing the amplifier can do to distinguish between two independent wires feeding two branches and one wire feeding two load branches. The difference in dissipation is therefore power that is not getting to the load.
The issue is of course, that we are not so inclined to consider the problem in terms of power delivered by the amp, dissipated along the way, and in the load. So, are uncomfortable with the analysis.
| quote: | Originally posted by Christer
I do buy Charles' explanation though. That one seems reasonable. |
He introduces factors which make the mathematical solution almost intractible, and that is "reasonable":confused:
Boy, what do you consider "unreasonable":confused:
Have a happy holiday..
Cheers, John |
|
|
| jneutron |
| quote: | Originally posted by SY
getting someone to define what they mean by these is as difficult and rewarding as trying to staplegun some goat liver to sheetrock. |
I'm afraid I'll have to defer to your experience on that procedure..
Man, you got some weird hobbies :eek: :eek:
Happy holidays Sy
Cheers, John |
|
|
| SY |
John: Sometimes reality makes the math intractable, but remember the drunk looking for his keys under the lamp-post...
Speaking of which, have a drink or three for me on Festivus! |
|
|
| Christer |
| quote: | Originally posted by jneutron
Any power that is dissipated within the wire is power that is not delivered to the load. That is what matters.
There is nothing the amplifier can do to distinguish between two independent wires feeding two branches and one wire feeding two load branches. The difference in dissipation is therefore power that is not getting to the load.
|
OK, I think I see the point now. In the case of one wire this extra power must cause an extra voltage drop, and since the amp is a voltage source, the resulting voltage at the loads will differ in the two cases.
However, the funny thing is, if you replace the two loads with a single load (a fullrange speaker, for instance) you will get a similar extra power component on the load itself, but there is no corresponding voltage or current to this power. Does that mean we actually have a similar effect within a load, that power is somehow wasted when we have more than one frequeny component? Now I am really getting :confused: . Have to think more about this after Xmas.
(EDIT: On second thought, I am probably just fooling myself now. So don't assume I believe in what I just wrote, but maybe I do? Hm...)
| quote: |
He introduces factors which make the mathematical solution almost intractible, and that is "reasonable":confused:
Boy, what do you consider "unreasonable":confused:
Have a happy holiday..
|
I am happy if a theory gives a qualitative explanation of a phenomenon. I am even happier if the theory also permits quantitative predictions.
Oh well, you're rigth, it's time to leave the forum for Santa now.
:santa2: :xmastree: |
|
|
| jneutron |
| quote: | Originally posted by SY
John: Sometimes reality makes the math intractable, but remember the drunk looking for his keys under the lamp-post... |
You saw me last night:confused:
All of the other parameters are confounding to the issue. The issue is the non linearity of powerloss within the wire..that nonlinearity forces a different node voltage that is now based on powerloss modulation. Once the standards for that non linear loss component have been set using this new information, the complexities of the actual drivers will go away.| quote: | Originally posted by SY
Speaking of which, have a drink or three for me on Festivus! |
Will do..
Cheers, John |
|
|
| jneutron |
| quote: | Originally posted by Christer
OK, I think I see the point now. In the case of one wire this extra power must cause an extra voltage drop, and since the amp is a voltage source, the resulting voltage at the loads will differ in the two cases.
However, the funny thing is, if you replace the two loads with a single load (a fullrange speaker, for instance) you will get a similar extra power component on the load itself, but there is no corresponding voltage or current to this power. Does that mean we actually have a similar effect within a load, that power is somehow wasted when we have more than one frequeny component? Now I am really getting :confused: . Have to think more about this after Xmas. |
For single loads, the loss in each part is of identical form.
For the single wire feeding two branches, that changes. All changes must be considered.
| quote: | Originally posted by Christer
I am happy if a theory gives a qualitative explanation of a phenomenon. I am even happier if the theory also permits quantitative predictions. |
It does. It predicts harmonic modulation products as a result of the branch structure, and the way to eliminate it.. This should be simple to measure as I detailed.
Cheers, John |
|
|
| poobah |
Hey guys,
I am buliding a huge spreadaheet right now illustrating John's theory. I am constructing it analyzing single wire behaviors rather than a bi-wire vs. single wire "showdown". Understanding the single wire effects makes the bi-wiring question more or less obvious.
The results I'm getting thus far suggest/confirm some interesting even-order distortion on the composite, sine plus DC, waveform.
I will zip/post this spreadsheet when all is done and you guys can get to shooting holes in it.
I could use some help with FFT function in EXCEL as it seems a real mess to me... The format of the output is not defined in the help files (or I can't find it)... of course, I'm supposed to know all this (but I don't). Any experts on the EXCEL FFT are invited to sound off here!
If I can't use FFT, I will fit spectra, one at a time by the Armstrong method using least sum of squares to get the fits.
Happy whatever all!
:cheers: :cheers: :cheers: :drink: :drink: :emoticon: :emoticon: :crackup: :dead: |
|
|
| jneutron |
Excellent.
I can't wait to see it on Tuesday.
Hopefully, I'll still be able to type by then..doing plumbing and wiring work monday.
Being an engineer, they will not allow me to touch anything I could hurt myself with at work (scissors, tape, paper, etc), so I have to endanger my body parts at home..
Your run of smileys is, um, consistent with my current condition..c3..
_:smash:
:dead:
Enjoy the holidays...
Cheers, John |
|
|
| poobah |
Cool,
Mske sure you use that $500/meter holophonic stuff if you're wiring your audio outlets... |
|
|
| lineup |
Regarding
Burn-in | quote: | As a general rule, take your time, and let the new components to burn-in.
A good idea could be to let the amp powered in, with a musical program,
and with the outputs loaded with proper resistors. |
A friendly advice at this forum.
From this I can conclude some of us think components in amplifiers
need to burn-in for a time.
I still dont think anything in an amplifer need to burn-in.
This is not to be mixed up with 'warming up'.
For example in Class A amplifiers takes some time
before component temperature settles at working level
and current levels get stable without too much drift. |
|
|
| serengetiplains |
| Lineup, there exist entire industries outside the audio industry that disagree with you on the matter of burn-in. |
|
|
| serengetiplains |
From the Elgar website:
| quote: | | Burn-in is at the heart of reliability in the market segments of today´s leading edge semiconductor and electronics manufacturing. |
|
|
|
| SY |
Isn't that burn-in for reliability rather than performance? For hi-rel stuff, one commonly runs devices for a time to get off the first part of the MTBF curve, i.e., a disproportionate number of failures happens early on and those failures are weeded out.
This, BTW, is the reason that extended service plans are so incredibly profitable for chain electronics stores. |
|
|
| poobah |
Right!
Google on "bathtub curve"... ;) |
|
|
| Tweeker |
| quote: | | I still dont think anything in an amplifer need to burn-in. |
Im going to disagree here somewhat. Theres one type of item in an amplifier that can be said to "burn in" without too much controversy. Electrolytic capacitors, they may reform under operating conditions.
Of course, some of the folks who really obsess over these things would rather have a sharp poke in the eye than use an electrolytic. |
|
|
| serengetiplains |
Re burn-in, another area for investigation concerns dielectrics, which can store electrical charges created during construction and handling. Capacitor and cable burn-in, so called, might in fact relate to eliminating or reducing these stored charges. Here's what Lynn Olson thinks of the matter:
| quote: | | my friend Gary Dahl has reached a breakthrough on conditioning cables and transformers - most of the coloration appears to be in the dielectrics, not the wire itself, and the dielectrics can be de-stressed by exposing them to high voltage and high frequencies for 24 hours. (100VAC and 100kHz, for example.) Our working hypothesis is that the fabrication process forces static charges into dielectrics, making them into low-quality electrets, with charges stored in the molecular structure itself. These charges appear to be relieved by a process similar to degaussing - by a lengthy exposure to high-frequency alternating fields. |
On a related note, Bob Pease has written about static charge build-up in teflon which, as the article describes, confounded the workings of certain very sensitive pieces of electronics, thus confounding the operators of that equipment who got X readings when they expected Y. You can read his article here. |
|
|
| lineup |
There might be one or several very small changes in a few components.
But they would most probably not have any possibility to effect overall performance at all.
Even if it was confirmed scientifically
that amplifiers need to burn-in to be able to deliver output
according to specifications,
I doubt I would worry and do anything different.
I would use my amplifier as normal.
And allow me to doubt, I suddenly one day ( when 'burnt-in-state' has arrived )
would notice a significant improvement in performance.
These theories and speculations are not, as far as I have seen, yet validated and documented.
For now, I have no good logical reason to buy them.
So I will wait with doing this.
:) |
|
|
| sam9 |
| quote: | | It a common problem with authors like Aczel and Elliot who claim to represent reason and science, they often throw the method out the window in regards to the characters, motivations and capabilities of those with whom they disagree. |
I have to take partial exception to this regarding Rod Elliot. Looking through the articles section of his website it's pretty clear that "argument by assertion" is generally not his style. He has put a lot of effort in to publishing experimental data behind his conclusions. If one is going to debate Rod convincingly it's a good idea to put a similar effort in to generating your own data.
It is true that when he reaches a conclusion that suggests someone is charging customers disproportionate amounts of money for equipment having an obviously minimal cost of manufacture he tends to take great offense. This is probably a sign of personal integrity as much as anything else. By contrast, I'm much more cynical by nature and get a chuckle out of some fool with more money than sense who pays thousands (of US$) for a pair of LM3886's plus assorted caps and resistors all inside a pretty box. I take a simple confirnation of BF's dictum that "A fool and his money are soon parted." (This is not a knock on the LM3886 just a recognition that one of special and remarkable virtues is that it *IS* cheaper than dirt.) |
|
|
| poobah |
Serengeti,
Please... please... please. |
|
|
| AcidOrangeJuice |
| quote: | Originally posted by widowmaker
citation:
"Tubes are great for high-powered
RF transmitters and microwave ovens
but not, at the turn of the century, for
amplifiers, preamps, or (good grief!)
digital components like CD and DVD
players."
Many deaf and stupid engineers write a lot of meaningless nonsenses... |
Could you clarify me why an engineer is "stupid or deaf" by this?
I have at least 10 years designing and building audio amplifiers without problems; and I can say to you that I agree with the author of this article.
In this point;
Could you explain me why any engineer with experience that considers the tubes (in audio amplifiers) as obsolete technology is "stupid or deaf"?
I wait for your answer. |
|
|
| analog_sa |
| quote: | Originally posted by AcidOrangeJuice
I have at least 10 years designing and building audio amplifiers without problems;
|
'Without problems'? You mean they don't burst into flames? Or they all sound amazing?
I somehow fail to believe that an outstanding amp can be designed or built 'without problems'. Unless you are simply cloning. Or your criteria is set too low. |
|
|
| pinkmouse |
:cop:
Guys, leave the personal stuff out of this discussion please. |
|
|
| gamma |
Hmmm I think "burn-in" is a reality. I'm member in a swedish hifi-forum. We had a meeting for a half year ago. Two identical tweeked DVD-player with diffrent "burn-in" time sounded diffrent. The player which was used longer sounded more open.
Besides..when I lived in gränna (a small town in sweden) a friend worked in capacitor-factory (RIFA) there. And they used a "burn- in" process which lasted for few hours. |
|
|
| rdf |
| quote: | Originally posted by sam9
I have to take partial exception to this regarding Rod Elliot. Looking through the articles section of his website it's pretty clear that "argument by assertion" is generally not his style. He has put a lot of effort in to publishing experimental data behind his conclusions. If one is going to debate Rod convincingly it's a good idea to put a similar effort in to generating your own data.
|
I'm glad it's partial sam9 because it's not really what I wrote. ;) It was in reference to the tendency of both (in Aczel's case 'tendency' is a soft word) to cast manufacturers of devices they consider ineffectual as snake-oil salesmen and charlatans. I made no comment on Elliot's methodology regarding physical devices, just people. |
|
|
| lineup |
| quote: | Originally posted by gamma
Hmmm I think "burn-in" is a reality. I'm member in a swedish hifi-forum. We had a meeting for a half year ago. Two identical tweeked DVD-player with diffrent "burn-in" time sounded diffrent. The player which was used longer sounded more open.
Besides..when I lived in gränna (a small town in sweden) a friend worked in capacitor-factory (RIFA) there. And they used a "burn- in" process which lasted for few hours. |
How much more open did it sound?
2-3 meters?
15 % ?
Twice as open?
:)
( Of course you used blind test, to exclude you all there biased eachother.
Anything else wouldnt be wise. ) |
|
|
| poobah |
| You're a good man Line-up... |
|
|
| Tweeker |
"Tubes are great for high-powered
RF transmitters and microwave ovens
but not, at the turn of the century, for
amplifiers, preamps, or (good grief!)
digital components like CD and DVD
players."
Many deaf and stupid engineers write a lot of meaningless nonsenses...
Well, even now, at the turn of the century, and nearing its own centenial, the triode is still the most linear gain device.
All of these active parts be they tubes, fets, or bjts have different character engineers can exploit to achieve their end goal. |
|
|
| serengetiplains |
| quote: | Originally posted by lineup
... to exclude you all there biased eachother. |
Come again? |
|
|
| gamma |
| quote: | Originally posted by line up
How much more open did it sound?
2-3 meters?
15 % ?
Twice as open?
|
?????????
Have you EVER noticed any diffrence between loudspeakers? ...and been able to quantify the diffrence in openness or size of soundstage?
And IF you not could quantify the diffrence...then it doesnt exist?:confused:
Edit: I had a very sceptical attitude to "burn-in"-effect before the test |
|
|
| SY |
| quote: | Originally posted by serengetiplains
Come again? |
John Broskie had some interesting things to say about that in his latest blog on tubecad.com. Ant behavior. |
|
|
| serengetiplains |
| One scientific question might be, does ant behaviour exclude the possibility that anyone, say, listening to preamps in a preamp shootout hears an audible difference between them? |
|
|
| SY |
| Nope. But it does mean that the tests of audible differences should also control for pack behavior. We really aren't consciously aware of it most of the time... |
|
|
| lineup |
| quote: | Whether the long burn-in is the result of dielectric forming,
or the quantum tunneling effect within the silver wire itself;
that remains for the scientists. |
By second thought, burn-in could have an effect, speaking silver wire.
Note: This does not automatically apply to amplifiers.
Could be because of one or both of these things:
1) Dielectric forming
2) Quantum tunneling effect
From this we see and learn that
what some people like to call Audio Lie
is in fact no lie at all.
:rolleyes: |
|
|
| poobah |
Seems to me that if we have break-in mechanisms for cables; shouldn't there also be a wear-out mechanism at play as well.
Surely someone should be able to hear when their cables are worn out. I am really surprised that the cable manufacturers haven't studied this as well and told us what to look (listen) for. |
|
|
| motherone |
| quote: | Originally posted by poobah
Seems to me that if we have break-in mechanisms for cables; shouldn't there also be a wear-out mechanism at play as well.
Surely someone should be able to hear when their cables are worn out. I am really surprised that the cable manufacturers haven't studied this as well and told us what to look (listen) for. |
Poobah,
You should "research" this and maybe use it to make some $$$ helping the marketing folks from the cable companies!
Seriously though, that one made me smile. |
|
|
| poobah |
| Thanks motherone! You watch... you just watch... somebody'll run with it. |
|
|
| motherone |
| quote: | Originally posted by poobah
Thanks motherone! You watch... you just watch... somebody'll run with it. |
Oh no, I totally am waiting to see it in an ad in stereophile 6 months from now. I can see it now:
"How old are your cables? Are you still using cables from 10 years ago? We all know the proven effects of Cable Burn-in. However, groundbreaking research by the Nostrum Cable Company has shown that continuous use of audio cables leads to detrimental effects. We have shown that due to magnetic phase shift properties caused by eddy currents in the cable, your dielectric may be migrating into your cable substrate! This leads to a collapsin of the soundstage, and greatly affects the Pace, Rhythm and Timing of your cables!"
"By using our new Cable Rejuvenator 3000, we can subject your cable to reversal of this process. The Cable Rejuvenator 3000 will recondition your cables to sound like they did right after you initially burned them in! "
"The Cable Rejuvenator 3000 utilizes quantum purification principles initially discovered by Jack Bybee. By combining Bybee's research with materials research from Shun Mook and C37, we've managed to create a device with unparalleled cable improving effects! Furthermore, if your new cables aren't broken in yet, Cable Rejuvenator with automatically find the sweet spot and break your cables in for you!"
"Cable Rejuvenator works it's magic on any cables! We include Cardas RCA connectors for Interconnects, Cardas 5-way Binding posts for speaker cables, Wattgate connectors for power cables, and even premium BNC jacks for you S/PDIF afficianados out there, and even high-grade RJ-45 jacks so that you can improve your Cat5/6/7 cables and increase your data transmission rates by up to 3%!"
"8 out of 10 audio reviewers agree that the Cable Rejuvenator is the best thing to happen to cables since Zip Cord!" |
|
|
| poobah |
You got me laughin' man. And you know you're right... my idea too...
And now I'm wondering... were I to make cables for $100 and sell them for $5,000... I guess I would break them in for my customers. Why don't these guys do this... seems like the least they could do? Or is that like getting a new car with a 1,000 miles on it and french fry grease on the back of the mirror?
;) |
|
|
| Tony |
| quote: | | Cable Rejuvenator works it's magic on any cables! |
LOLZ!!!! reminds me of the picture tube rejuvenator in the olden days! then you can actually sparks inside the tube as cobwebs between the cathode and G1 are being burned., and very effective too!:cheers: |
|
|
| motherone |
| quote: | Originally posted by poobah
You got me laughin' man. And you know you're right... my idea too...
And now I'm wondering... were I to make cables for $100 and sell them for $5,000... I guess I would break them in for my customers. Why don't these guys do this... seems like the least they could do? Or is that like getting a new car with a 1,000 miles on it and french fry grease on the back of the mirror?
;) |
Thanks.. That's a good question -- why aren't they burning them in for you?
I do think it's funny how cables that cost maybe $100-200 for a DIYer to make get resold at $5k, and everyone lauds what miracles they work. Pretty sad stuff. |
|
|
| poobah |
be vewwy vewwy kewful...
It just occured to me. Were cables sold broken in, there would no plausible reason to account for the fact that they sound the same as the cables they replaced. Weeks go by, expectations morph into observations... all is well. |
|
|
| Tone22 |
Hello all,
For my first post I'd like to donate my $0.02 worth on a subject I have a little experience with.
Cables can sound old and dull. I once forgot to take an interconnect off of a cable break-in rig I made...oh, more than a half dozen years or so ago, and it was on there for a whole day.
That doesn't sound like much but I was using a speaker level source--about 15 watts average. Normal interconnects never see that much voltage or current.
Well, I couldn't use that pair of interconnects for much of anything to do with a stereo any more--the one was so much darker sounding than the other it wasn't funny. (It was the one that was left on the break-in rig for way too long that was the dark sounding one.)
The concept of break-in is controversial in lots of areas, audio and musical. Engineers often listen with their calculators. :) |
|
|
| lineup |
CABLE COOKER[tm]
| quote: | | ... allows break-in and conditioning of interconnects, speaker cabling, and power cabling simultaneously |
The Cable Cooker[tm] speeds up burn in of signal-, speaker- and power cables.
Without making any sounds!
You should observe correct direction of cables. From input to output.
If we are to believe feedback from buyers
they are very please with results.
Note!! This is not an advertise, but an information
and food for our discussion on eventual burning in effects in audio gears. |
|
|
| AcidOrangeJuice |
| quote: | Originally posted by analog_sa
... Unless you are simply cloning. Or your criteria is set too low. |
That I know, the intention of any good forum (as here) is to debate things or different points of view as adult people.
If you are not able of this, because you are not able to control your temperament, even the point to insult, then simply, you don't debate.
The insults without justification will not help to you in your explanation, all the opposite.
| quote: | Originally posted by analog_sa
... You mean they don't burst into flames? ... |
The only thing that "burst into flames" without necessity was your temperament.
| quote: | Originally posted by analog_sa
Or they all sound amazing? |
Yes, they sound amazing.. And this has been my work for a long time; but probably, you don't understand it, because you don't have the experience.
| quote: | Originally posted by analog_sa
I somehow fail to believe that an outstanding amp can be designed or built 'without problems'. |
I'm sorry that you think of this way. |
|
|
| AcidOrangeJuice |
| quote: | Originally posted by Tweeker
Well, even now, at the turn of the century, and nearing its own centenial, the triode is still the most linear gain device. |
The transfer functions of triodes and mosfets are not very different.
Ironically; the more common single-ended class A triode amplifiers in the market have in average levels of harmonic distortion around of 10% :dead: in nominal power output. In addition, these amps. can't maintain the output voltage gain levels constant with the frequency; in other words, these amps. don't have a linear frequency response; and this is due to the fact that the triode can't maintain the voltage gain levels constant independently of the load impedance, due to the low damping factors what commonly these amps. exhibit; and this is what you call a linear device? C'mon!!
I could not consider that any amp. with high levels of distortion and a non-linear frequency response could be an Hi-Fi amplifier.
The basic concept of Hi-Fi audio is to reproduce of music signal as faithfully as this is possible, and these type of amps. are poor in this.
On the other hand, a well-designed Hi-Fi transistor audio amplifier is able to maintain a flat frequency response, independently of the load impedance. This is due to the fact of a good damping factor, very common in the transistor amps. well-designed, which many tubes amps. lack. In addition, very low levels of harmonic distortion are present in these well-designed transistor audio amps.; (less than 0.1% typical); as also an excellent signal to noise ratio, around 90db to 120db typical.
In conclusion, a well-designed transistor amp. is most similar to which would be an ideal amplifier; and by a fraction of the cost of an tube amplifier with inferior performance.
I remember an anecdote, which happened in the beginning of the 80's decade. Bob Carver, a excellent and recognized audio amplifier designer put in evidence the truth about of the myth tube amp.
In that moment, Stereophile magazine was promoting a model of tube amp. to being supposedly the top of the art of audio (of course, very expensive). Bob Carver, with the intention to demonstrate that this amp. was not nothing special invited to the audience of Stereophile magazine to a double-blind audio test, in where was compared the mystic tube amp. with a very cheap low performance transistor amp. The results were that the audience was not able to distinguish a difference between the two amplifiers.. In other words.. both sounded equal !!!
You readers, draw their own conclusions from this. ;) |
|
|
| moray james |
quote: It just occured to me. Were cables sold broken in, there would no plausible reason to account for the fact that they sound the same as the cables they replaced. Weeks go by, expectations morph into observations... all is well.
Have you never even once found a cable that you believed sounded better than what you have been using? Does this mean that you are using what ever came in the box? Have you ever changed interconnects for any other reason than one of them wore out or broke? Do you mean us to understand that all interconnects and speaker cables or power cords sound the same in your system? I ask in all sincerity as I find that I have never known that to be always the case. Or perhaps you have noticed differences but have felt that the sound was different not better?
Differences that I have heard have in some cases have been astounding while in other situations far less convincing. For the most part though I have found that good interconnects can and most often do make the difference in any given system.
I might also ask if you do or do not believe that components benefit from a burn in period?
There are obviously differences in opinions and that's fine. I would think though that long before anybody thinks to enter into a scientific study of some perplexing oddity that it was all brought about by repeated comments/observations of non scientific types. So I have difficulty with the attitude toward non scientific comments presented on this forum. Would it not be just as easy for the non scientific observers to call the scientists to task to explain everything since science has all the answers? That obviously is not the case nor is it a reasonable posture. I feel though sometimes that that is the kind of stance that those with a degree or two may infact be taking. I was under the impression that it was science's tact to take the high road. If you can prove yourself correct and even if you cannot you can hold onto your beliefs but I sence there are at times some smug attitudes. That comment can apply to both sides of the debate and it helps neither side.
I hope that we can discover what is going on as that then becomes a win win situation. Otherwise we end up with a group on either side of a fence pointing and calling out at the other side while nothing changes. This can't go on forever can it? Regards Moray James. |
|
|
| Cal Weldon |
| quote: | Originally posted by moray james
This can't go on forever can it? |
Forever for now. |
|
|
| poobah |
Moray,
Would you agree that if there is a break-in mechanism, which indicates a tangible physical change on some level, that there might also be a wear-out mechanism based on a continuation of the same, or other, physical changes? We have one report of a wear-out mechanism.
My question would be, if there are indeed changes taking place in a conductor, why have these changes only shown themselves in audio and not in other fields that demand greater accuracy? It is often the exceptions, rather than the norms, that expose hidden truths.
I suspect that any legitimate testing done in the name of resolving these issues would be summarily dismissed because the test probes for the instruments might not have been broken in properly.
:xeye: |
|
|
| moray james |
A cap can form and if you leave it long enough it can to some degree get itself unformed. Cables can burn in or charge up so why not the reverse. I would suspect the dielectrics are at the root of things in a cable.
Now how about answering those questions? I might also add to the list. Did you ever believe that all amps sound the same because they measured the same?
In most areas there are many who do a fine job at what they do however a select few for what ever reasons excell far beyond the norm. Does that make them wrong because statistics say they are just an odd group outside of the norm?
The human brain is as good as it gets on this planet and nothing can touch it yet. The ear/brain combination is a wonderous thing. Show me a machine that can match the brain. This is really getting to be a bit of a drag. New year comming up there is time yet. Regards Moray James. |
|
|
| Tone22 |
Hello all,
Engineers LIKE to listen with their calculators. OK. That's fine. Here goes another $0.02...
Now, distortion is a concept that is supposed to help designers to make a better sounding what ever. The key word is "supposed-to."
"If it sounds good and measures good, it is good. If it sounds good and measures bad, you are measuring the wrong thing."
A quote from the chief engineer of H. H. Scott, many many moons ago.
Double blind audio tests are invalid. Unfortunate but true. They use a multi-stimulus approach. Traditional double blind tests use a single stimulus--only.
Audio is not a single stimulus. 3-D qualities, image specificity, midrange tonal quality, bass tonal quality, HF tonal quality, image size, overall tone, etc. There are a vast array of things to pick out and listen to with music. You get to pick only one for the subject matter of a properly handled audio double blind test--no one does though. "Better" is not specific, it is vague. The multi-stimulus approach alone renders any audio double blind test invalid.
Double blind audio tests are done in strange settings (to the participants) with unfamiliar equipment, and often with unfamiliar music. How do you know when something is more to your liking? When you've lived with it in your situation. This is another reason double blind audio tests are invalid.
The sound of the power changes so you can't use wall power. Batteries are a must. Anyone use them for the entire system, or any part of them--I doubt it.
Everything in the room is part of the sound of that system. People move around. Things come and go and no one "thinks" this is a problem... More reasons why current double blind tests for audio are fatally flawed.
Measurements are a tool, not the art. :) |
|
|
| Christer |
| quote: | Originally posted by gamma
Hmmm I think "burn-in" is a reality. I'm member in a swedish hifi-forum. We had a meeting for a half year ago. Two identical tweeked DVD-player with diffrent "burn-in" time sounded diffrent. The player which was used longer sounded more open.
|
So, do you mean this test was done in the way I suggested earlier in this thread?
| quote: |
Besides..when I lived in gränna (a small town in sweden) a friend worked in capacitor-factory (RIFA) there. And they used a "burn- in" process which lasted for few hours. |
I strongly suspect this referred either to the forming process, which is a necessary step in the manufacturing, or to a burn-in phase for reliability reasons, which is commonly done with many components to reduce early failures. AFAIK, RIFA do not manufacture any capacitors intended specifically for audio use, so we can rule out that they burn in any capacitors to supposedly sound better. They do specialize in high-reliability, long-life capacitors though, so burning in for reliability purposes is to be expected. |
|
|
| lineup |
| quote: | | Double blind audio tests are invalid. Unfortunate but true. |
The usual argument to avoid the dreaded blind test.
Beause deep inside most those who say they can hear
they know they might hear nothing.
If they were sure, they wouldnt be so hostile to blind test.
They would have nothing to fear from a test.
They are afraid to know the truth.
It really is a pity.
Because we should not believe in illusions and take them for real.
It is to deceive your self.
Within medical industry, to test medicin they use blindtests.
They have at least two groups.
One get sugar pills and one get the medicin.
It would hardly be great for results
if telling each group what type of pills they have got. |
|
|
| SY |
As I've said over and over, we routinely do just this kind of controlled tasting in the wine business. No excuses about blind tests, you either can get a difference or you can't.
The main issue with controlled testing in audio is that it's a pain to set up and do properly, and that's not as entertaining as speculating about phonon-meson resonances in cable dielectrics. |
|
|
| lineup |
| quote: | Originally posted by SY
... is that it's a pain to set up
... and do properly,
... and that's not as entertaining |
SY
this is excuse number 2, 13 and 41
from the Audiophile listener's handbook
How to Avoid Taking Blindtests
:clown: |
|
|
| ctviggen |
| I try to do blind testing on myself whenever I can. I'll have my fiancee change between two items and have me tell her which is best. |
|
|
| rdf |
No lineup, the problem with a great many double-blind tests is they're structured like the AES-sponsored one described below:
http://stereophile.com/asweseeit/107/
That was the 91 AES Convention in New York. My brother, who at the time was a lead audio designer for Nortel and made a living from structured audio testing, attended a similar demonstration at a late-Eighties AES conference in Toronto with one of his peers. They found the methodology so unprofessional and flawed as to leave mid-point to go harmonica shopping instead.
This discussion would be better served if posts like yours dealt more with the test proof you so adamantly believe exists instead of ad hominem and unprofessional characterizations of personalities. Unless of course you want to present proof it's your field of speciality and show the research.
Frankly I'm dismayed the moderators didn't step in during the last five pages or so. |
|
|
| phase_accurate |
To distract from validity-of-testing-issues I made a SPICE model for the bi-wiring case and it does indeed show differences in nonlinear distortion.
Although they are very small with my model. Furthermore I don't know how much the typical signal-dependant impedance fluctuation of a driver is in reality.
I will post the schematic and FFT as soon as I have time. Maybe in the meantime someone comes up with real-life figures of aforementioned nonlinearity so I can set the parameters of my model accordingly.
Regards
Charles |
|
|
| gamma |
| quote: | Originally posted by Christer
So, do you mean this test was done in the way I suggested earlier in this thread? |
Do you mean this?
| quote: | | Take two identical, brand new pieces of equipment, that are supposed to benefit from burn in. Listen to them and confirm you can't hear any difference. Then burn in one of the pieces, but not the other one. After that, perform a DBT. |
honestly: No it wasnt a blind test at all - but "to my defence" I can say I were VERY sceptical to "burn-in-effect" before the test. |
|
|
| jneutron |
| quote: | Originally posted by phase_accurate
To distract from validity-of-testing-issues I made a SPICE model for the bi-wiring case and it does indeed show differences in nonlinear distortion.
Although they are very small with my model. Furthermore I don't know how much the typical signal-dependant impedance fluctuation of a driver is in reality.
I will post the schematic and FFT as soon as I have time. Maybe in the meantime someone comes up with real-life figures of aforementioned nonlinearity so I can set the parameters of my model accordingly.
Regards
Charles |
Assume the wire run is #12, the length is ten feet, using two neutrik speakons.
The round trip wire resistance is 2.02 milliohms per foot times 20, or 40.40 milliohms.
The connector has 3 milliohm contact resistance guaranteed, total of 12 milliohms.
Assume the woofer driver impedance has a minimum of 4 ohms, the tweeter 8.
Assume the power required of the woofer is about ten times that of the tweeter. For a 1 amp peak tweeter signal, the woofer will draw up to 4.(close to the square root of 10).
So you will have a cable resistance total of 52 milliohms, and the simulation will look for the difference between one ampere sine across 52 milliohms, and that one ampere riding on a 4 ampere DC current across that 52 milliohms.
I do not have typical binding post resistance values..
Cheers, John |
|
|
| Christer |
Gamma,
Yes, that is what I meant. So OK, you didn't do a blind test. However, the other important thing is if you did listening tests before to convince yourselves that you couldn't hear any difference before burning in one of the units. That is necessary to esatblish that the perceived difference can be attributed to the burning in with reasonably certainty. |
|
|
| phase_accurate |
Hi John
I can take these of course. I actually took 50 mOhms for a "common" cable and two times 100 mOhms for the bi-wiring case.
I took same signal levels for both LF and HF. Your choice is more life-like and would even show more influence on the tweeter.
What I am still unsure about is the amount of driver non-linearity involved.
As you might have recognized I am not trying to prove your theory but mine (I am that selfish sometimes).
Regards
Charles |
|
|
| jneutron |
| quote: | Originally posted by phase_accurate
Hi John
I can take these of course. I actually took 50 mOhms for a "common" cable and two times 100 mOhms for the bi-wiring case.
I took same signal levels for both LF and HF. Your choice is more life-like and would even show more influence on the tweeter.
What I am still unsure about is the amount of driver non-linearity involved.
As you might have recognized I am not trying to prove your theory but mine (I am that selfish sometimes).
Regards
Charles |
That's just fine..all the info is useful.
I used 52 mohm as the "best case" setup.
Try with a #16, 5.15 mohm per foot, total 100 milliohms.
I recommend this simulation:
Two branches fed from a zero impedance voltage source, the source a 5K sine at 8 volts.
output 1...a 100 milli resistor feeding an 8 ohm load through a capacitor of appropriate value.
output 2...an identical circuit to the first, with a small adder. Pull a DC current from the cap-resistor node to ground using an ideal infinite impedance current sink. (on second thought, I gotta think about that a little, there may be something funny in doing it this way, you may need to include an arbitrarily large inductor to keep the hf out of the sink.).
Difference the outputs. That is the distortion.
You could just as easily use an inductor with 4 ohm load in circuit 2, and add the dc voltage to the voltage source.
I agree that driver non linearity is of concern...but who cares about that if the signal being presented to it is already non linear??
I learned long ago, if a large complex analog system is not performing correctly, the first thing done is to make sure the power supply is operating within tolerance...otherwise, troubleshooting the circuitry that uses that supply is useless.
Cheers, John |
|
|
| serengetiplains |
| quote: | Originally posted by SY
As I've said over and over, we routinely do just this kind of controlled tasting in the wine business. No excuses about blind tests, you either can get a difference or you can't.
The main issue with controlled testing in audio is that it's a pain to set up and do properly, and that's not as entertaining as speculating about phonon-meson resonances in cable dielectrics. |
SY, am I to take from this that you think our taste and hearing senses respond similarly to blind testing? It would seem to me almost an evolutionary imperative that the taste sense be able very quickly to differentiate subtle differences, as those differences could carry ramifications for one's health---no small matter in the evolutionary mix. I cannot think of a similar rationale for hearing. In my own personal experience of listening for audible differences, I require as much as several hours to hear some of the more subtle differences, which sometimes appear to me as a subtle grating that might hit me on musical peaks etc. Give me two wines and I can tell A from B within 5 seconds. I don't see these processes as closely comparable. |
|
|
| jneutron |
| quote: | Originally posted by serengetiplains
SY, am I to take from this that you think our taste and hearing senses respond similarly to blind testing? It would seem to me almost an evolutionary imperative that the taste sense be able very quickly to differentiate subtle differences, as those differences could carry ramifications for one's health---no small matter in the evolutionary mix. I cannot think of a similar rationale for hearing. In my own personal experience of listening for audible differences, I require as much as several hours to hear some of the more subtle differences, which sometimes appear to me as a subtle grating that might hit me on musical peaks etc. Give me two wines and I can tell A from B within 5 seconds. I don't see these processes as closely comparable. |
Differentiate the same wine from the same vineyard from two consecutive years, or from the same year using wine from new oak or 5 year old oak, or made from different vendors using oak from different locals.
Heck, even I can see through that argument.
Cheers, John |
|
|
| poobah |
Hey Neutron,
Your theory re biwiring has as much to do with fidelity over a single wire as it does the merits of bi-wiring. How 'about a new thread as this thread contains many other (9?) contentious and distracting issues?
There is something weird about all this... it seems to foul up superposition. |
|
|
| serengetiplains |
John, I'm not simply throwing up arguments, as you perhaps imply---I'm looking for an adult conversation---but giving my experience. My wine tasting sensitivity (nothing you would know about) is at a high level so, yes, new oak, 5 year oak, easy to discern; wine from two consecutive years, even easier ... and all and any within the first taste.
Essential to one's taste or hearing sensitivity is the length of time one has given attention to developing that sensitivity---no overnight Robert Parkers. For my part, I have noticed a difference in my taste and hearing sensitivities and have perceived, as I intimated previously, a difference between the time required to discern audible subtleties. I say "audible subtleties" well aware that, with increasing time between listening sessions, factors enter in to confound the objectivity of the comparison such that "subtleties" I might claim to hear might not exist. I'm personally unaware of a solution for that problem, but I'm far from convinced that every audible difference that can be heard can be perceived within the same time frame. Video is of course a different animal altogether as not only are our eyes very fast to perceive very small differences, a true A/B test can be performed simultaneously. Wine and audio comparisons are unlike video comparisons in this regard. |
|
|
| jneutron |
| quote: | Originally posted by poobah
Hey Neutron,
Your theory re biwiring has as much to do with fidelity over a single wire as it does the merits of bi-wiring. How 'about a new thread as this thread contains many other (9?) contentious and distracting issues?
There is something weird about all this... it seems to foul up superposition. |
Yes, a new thread is warranted. There is too much noise on this channel as the origional poster covered so many different topics..
And, yes, it would appear that if my theory and analysis holds up, it does in fact demostrate a violation of superposition. If that is the case, then the theory of superposition needs to be either corrected or abandoned. I believe it would most likely be modified to fit branch issues. But I'm discussing this with a few of my collegues, they are pretty smart. One in particular is used to my goofball ideas, but listens. As on occasion, I am correct..
I have broken laws before, but never with intent to do so.:bawling:
I ran the analysis using 4 amps dc and 1 amp ac into both a 50 milliohm (10 feet of #12) and a 300 milliohm wire run (30 feet of #16)..the numbers are staggering in the 300 milliohm run.
If my analysis is correct...I'm gonna have fun..
Cheers, John |
|
|
| jneutron |
| quote: | Originally posted by serengetiplains
John, I'm not simply throwing up arguments, as you perhaps imply.... |
I was not implying that, it was more like an unstated accusation..it would seem that I owe you an apology...Sorry..| quote: | Originally posted by serengetiplains
My wine tasting sensitivity (nothing you would know about) is at a high level |
Your statement is accurate at two levels..I know nothing about your abilities, and do not have that ability..I can, however, tell a red wine from a white...eyes open, of course.;)
Cheers, John |
|
|
| poobah |
I am with ya John,
I have followed along with the math and see the weirdness myself... I started running sims but decided to persue a purely math approach. We should be able to prove it all one way or the other... |
|
|
| SY |
| quote: | Originally posted by serengetiplains
SY, am I to take from this that you think our taste and hearing senses respond similarly to blind testing? ...
Give me two wines and I can tell A from B within 5 seconds. I don't see these processes as closely comparable. |
It's not so easy when you're trying to determine the potential organoleptic consequences of printing the cork with ink from Vendor A versus Vendor B... Yet these sorts of things are life and death decisions for my company, and there's no way we or our customers would accept anything less than proper blind tests.
There are analogies between different sorts of sensory testing. In my last job, I did haptics, now I do organoleptics. Different senses, yet all of the human biases and need to eliminate them to get to what's real are still the same. My friends who do optical stuff tell me the same thing.
BTW, I've tasted with Parker and I'm a lot less impressed than you are! ;) ;) ;) |
|
|
| serengetiplains |
SY, I agree, and Parker's not to me the be-all of wine tasters; I used him as an accessible example. I prefer the Brits, myself. Have you seen Mondo Vino? Interesting perspective on Parker and his Mondavi/Napa links etc. Ah, the world is corrupt.
Wine tasting seems to me more amenable to A/B testing, and for that reason alone should be used in the wine industry. I can listen to music for hours at one sitting. I typically can't drink wine for hours at one sitting. Nor can I compare what ears and taste buds might perceive (assuming, as regards the latter, I'm still conscious) after several hours' respective indulgence.
I'm suggesting that, in music, that which grates on one's hearing (or brain) after two days/months/years might not be (is not IME) perceptible in 10-20 minutes' A/B. But 10-20 minutes is a more than adequate amount of time to perceive the true quality of a wine. If this is indeed true, and if long-term irritations do figure in audio satisfaction, as IME they importantly do, A/B testing shows its limitations. |
|
|
| serengetiplains |
| quote: | Originally posted by jneutron
I was not implying that, it was more like an unstated accusation..it would seem that I owe you an apology...Sorry.. |
Accepted and appreciated, John. I wish I had engineering skills, but alas do not, and I appreciate what an engineering perspective brings to the audio arts. I am not, however, equally crippled as regards a scientific understanding generally, as science is about the only thing I read in my spare time. |
|
|
| AcidOrangeJuice |
| quote: | Originally posted by rdf
No lineup, the problem with a great many double-blind tests is they're structured like the AES-sponsored one described below:
http://stereophile.com/asweseeit/107/
That was the 91 AES Convention in New York. My brother, who at the time was a lead audio designer for Nortel and made a living from structured audio testing, attended a similar demonstration at a late-Eighties AES conference in Toronto with one of his peers. They found the methodology so unprofessional and flawed as to leave mid-point to go harmonica shopping instead.
This discussion would be better served if posts like yours dealt more with the test proof you so adamantly believe exists instead of ad hominem and unprofessional characterizations of personalities. Unless of course you want to present proof it's your field of speciality and show the research.
Frankly I'm dismayed the moderators didn't step in during the last five pages or so. |
I disagree with you at all.
Stereophile is a magazine which obtains many money with the sponsors of speaker cables and power cables. The doctrine the Stereophile is: the most expensive equipment is the best!!.
As the DBT are a latent danger for the vendors of snake oil; I doubt very seriously that Stereophile (who sponsors many of these mystics products of doubtful credibility) could have a position in favor of the DBT.
That if is a fact proven and verified is that DBT, when are done well, are a powerful tool in order to verify if really an AUDIBLE difference exists.
As a proof, DBT are used almost daily in order to improve and to fix perceptual lossy audio codecs (as mp3 or vorbis for example) and this has worked successful. For example, LAME mp3 encoder (which is one of the best mp3 encoders available in this moment) has been improved (with extensive DBT tests with many people) even the point that with specific settings, recommended by the developers, you can obtain transparency (transparency is the term used to define the point which doesn't exist perceivable audible differences between the original source audio file and the mp3 encoded file).
Due to the nature nonpredictable of lossy audio compresion algorithms is not possible to use measuring instruments commonly used in electronic design. These are perceptual audio codecs algorithms, and, that I know, the only effective way in order to improve is with DBT tests.
Even the same creators of the mp3 format (Fraunhofer scientist institute in Germany) have said this. Without the DBT tests used extensively there, had been impossible to develop efficient audio lossy encoders.
In my own experience, I have used DBT tests with the intention to improve mp3 encoders too, and I have been able to see that this really works, until finding very subtle differences.
It's true that to develop a DBT tests in hardware is more difficult, but nonimpossible. If your brother could not develop a hardware DBT test is because the circumstances did not allow it; but this is not a fault of the DBT test methodology. Another people, as for example Bob Carver, have been able to do this successful. |
|
|
| lineup |
I see many situations where a blind test is the only alternative
to find out what is a real sound difference and an imaginary illusion.
This is not unique for audio.
Blind tests is the only instrument to get knowledge
in many other areas.
Question is why many refuse to recognize this test method within audio.
When it is a valid way to investigate things,
and used to verify scientific works.
If you do not know your own mind, you do not know much,
because your mind is the filter of reality around you. |
|
|
| AcidOrangeJuice |
| quote: | Originally posted by lineup
... Question is why many refuse to recognize this test method within audio ... |
Because many vendors of snake oil in audio had been without work.
It's very suspect when any person rejects a DBT. For me, this is a signal which the person has something to hide. |
|
|
| serengetiplains |
| quote: | Originally posted by lineup
If you do not know your own mind, you do not know much,
because your mind is the filter of reality around you. |
Lineup, if your mind is the filter of reality as you suggest, there then exists no reality but that which the filter in your mind says is reality, which "reality" can only therefore but reflect that filter, and nothing else. But what, then, is meant by "reality"?
I think it germane, when speaking to the issue of A/B testing, to ask just what level of subtlety that testing reasonably might be expected to identify. If important elements of an audio signal fall below that threshold, A/B testing is useless respecting those elements. |
|
|
| phase_accurate |
O.K. Here it is:
The two drivers are R1 and R2. The nonlinear resistance of the drivers is formed by the multipliers and voltage sources. The gain of the voltage sources is set such that the resistance nonlinearity is approx +-3% @ 1 Volt peak. As mentioned before I don't know what the actual nonlinearity with real drivers is (any hints or tips ?).
The drivers are crossed over with an LR2 @ 1 kHz. The nonlinearity of a real-life crossover is neglected but it can be assumed that it would only make matters worse.
Keep in mind that this model can only take the mutual influence on the electrical side into account. So I "generously" omitted the nonlinear transfer from voltage to sound pressure which can make matters worse or better. The same accounts for the acoustic summation of the signals.
The arrangement is fed with 1 Volt peak @ 500 Hz and the with 0.25 Volts (i.e. 12 dB less) @ 2kHz. Single- and bi- wiring can be changed by changeing the values of R3 to R4.
I will post the simulation results in subsequent posts.
Regards
Charles |
|
|
| phase_accurate |
This is the simulation for the single-wire case
The interesting part is the signal levels at 500 Hz 1 kHz and 2 kHz:
Woofer Tweeter
500 Hz 1.255 V 317 mV
1 kHz 22.9 mV 2.08 mV
2 kHz 77.2 mV 312 mV
Sidenote: As one can see - the tweeter will generate harmonics of the woofer signal as well. |
|
|
| phase_accurate |
This is the simulation for the bi-wiring case. We now have two wires with 100 mOhms each - instead of once 50 mOhms.
Woofer Tweeter
500 Hz 1.24 V 320 mV
1 kHz 22 mV 1.5 mV
2 kHz 77.9 mV 309 mV
We can see a 25 % reduction of the 1 kHz content "accross the tweeter leads". Though any other voltage changes much less than that.
So there must be at least subtle differences between single-and bi- wiring that are more than just frequency-response irregularities. This mechanisms might also be another argument for AMPS with a (reasonably !) high DF.
Conclusion: If one doesn't use multi-billion-$ cables* this tweak might be a reasonable one to try out. Not for me though - I am a step ahead by running active. :cool:
Regards
Charles
* If you SELL said cables then this tweak is always reasonable. :devilr:
Edit: Tried to make the tables with the values more legible but my changes don't have the same effect on the editor window than they do with the "real" view. |
|
|
| darkfenriz |
Hey
back to topic
I think how many make their living from these lies or truths being still unanswered.
Today buying an audio equipmnt. is like answering 'philosophical' questions and answering yourself what you believe in. |
|
|
| gmarsh |
Read the article, haven't read the 19 page thread, but i'll add my opinion:
Cables: I've actually worked with one particular 'high end' speaker cable that had zobel networks and other things built into a 'mystery box'... this was after one of my amplifier designs went unstable with it attached. I wouldn't go as far as to say all speaker cables sound the same, but I'll certainly say that you're safer buying lamp cord.
Tube amps and LP's: Tube amps have that distinct warm, even-order-harmonic sound. LPs can sound awful, especially when you're using a cheap turntable. For accurate audio reproduction, they're both terrible! But I grew up listening to my dad's LPs through a tube amp and I *love* that sound, despite the scratches and pops and harmonics and all that other stuff...
Burn-in lie: A properly designed piece of modern, digital/solid-state audio equipment won't burn in. But speakers age - spiders and surrounds get softer with more use, I've seen this first-hand in thiele-small measurements of speakers, and it can create big changes in sound. So full systems do "burn in", but I wouldn't finger the CD player or amplifier as the culprit...
Golden ear lie: Unfortunately, years of audio equipment design and DSP hardware/code work have left me with a trained ear for distortion. Golden ears do exist, and I'm ashamed to say I'm one of them. |
|
|
| jneutron |
| quote: | Originally posted by phase_accurate
This is the simulation for the single-wire case
The interesting part is the signal levels at 500 Hz 1 kHz and 2 kHz:
Woofer Tweeter
500 Hz 1.255 V 317 mV
1 kHz 22.9 mV 2.08 mV
2 kHz 77.2 mV 312 mV
Sidenote: As one can see - the tweeter will generate harmonics of the woofer signal as well. |
To keep the math at a reasonably low level, I used DC for the confounding signal. That prevented the product of two sines, as the power at the cable R is (A + B)2 or (A2 + B2 plus 2 AB)....the voltage drop across the cable R then has a sqr(2AB) built in, hence the sidebands.
Using the multipliers in the simulation introduces square (or 2 omega) components which blur the issue of harmonic distortion caused by the cable resistance itself. Would it be possible for you to run this simulation with pure load resistances, and at 4 amps lows/1 amp highs as I proposed?..After all, this mechanism works as current squared, I think higher power levels will cause more non linear grief...thank you in advance.
| quote: | Originally posted by phase_accurate
Woofer Tweeter
500 Hz 1.24 V 320 mV
1 kHz 22 mV 1.5 mV
2 kHz 77.9 mV 309 mV
We can see a 25 % reduction of the 1 kHz content "accross the tweeter leads". Though any other voltage changes much less than that.
So there must be at least subtle differences between single-and bi- wiring that are more than just frequency-response irregularities. This mechanisms might also be another argument for AMPS with a (reasonably !) high DF. |
Or, an output impedance that can be set negative to zero the wires out? Or, pulling the feedback from a second set of speaker terminals, ones which tap in at the nodes of the crossover network.| quote: | Originally posted by phase_accurate
Conclusion: If one doesn't use multi-billion-$ cables* this tweak might be a reasonable one to try out. Not for me though - I am a step ahead by running active.. |
By trying power levels consistent with reasonable listening, the non linearity may be far more important. If so, this analysis may require establishing a different set of guidelines for wire guage, based on the speaker's multiplicity, single, two way, three way, etc.
Thanks for the effort.
Cheers, John |
|
|
| phase_accurate |
Hi John
I will do it tomorrow.
Regards
Charles |
|
|
| jneutron |
| quote: | Originally posted by phase_accurate
Hi John
I will do it tomorrow.
Regards
Charles |
I'll start a new thread to cull this analysis topic away from this one. Please post it there.
Thanks, John |
|
|
| rdf |
| quote: | Originally posted by AcidOrangeJuice
That if is a fact proven and verified is that DBT, when are done well....
It's true that to develop a DBT tests in hardware is more difficult, but nonimpossible. If your brother could not develop a hardware DBT test is because the circumstances did not allow it; but this is not a fault of the DBT test methodology. Another people, as for example Bob Carver, have been able to do this successful. |
That's my point AOJ, the DBTs done by the AES which I've been able to find used very poor methodology. I anticipated the Stereophile link would be subjected to the criticism they lied to sell product so for independent confirmation I used the example presented by my brother. I don't understand how you arrived at the conclusion he structured DBT's for consumer audio or had met with failure. His background is in telephony and if you've ever used a Norstar or Venture you've | | | |
