I have a EE degree what are yours? From the the way you balk at any mathamatical proof I would guess very little. Because I go to higher authority I am wrong? You sound like a lawyer (a bad one). Any way we are talking about Dr Leserf and his proof (yes PROOF). A cable only has resistance, and reactance, its not that complicated. Have you looked thru the rest of his audio website, he knows how to measure (when he has to) as well as do the math, he's a real physicist: observation (measurements) is used to support theory.
Is the only proof you will accept subjective?
I honestly don't understand the suggestion SY is acting in an inconsistent manner, his recommendation of the JJ appears to me in line with the context of almost everything he's posted here. The few deviations are at the level of human fallibility. I obviously have strong issues with the quality of the research he claims closes the topic of device audibility but few here, if any, outdo him in technical consistency.
cbdb, you're not the only one in this forum with a BAScEE. Widen your perspective. BTW, your synopsis misses Leserf's notes on screening, component interaction and non-linear contact effects. If you peruse the forums, SY has written of personal experience with cable effects that escape Leserf's breakdown. Granted, those effects also had solid engineering explanations, but it's also true strong engineering mindsets are willing to consider cable effects that would have been relegated to the category of floobie-dust 20 years ago.
cbdb, you're not the only one in this forum with a BAScEE. Widen your perspective. BTW, your synopsis misses Leserf's notes on screening, component interaction and non-linear contact effects. If you peruse the forums, SY has written of personal experience with cable effects that escape Leserf's breakdown. Granted, those effects also had solid engineering explanations, but it's also true strong engineering mindsets are willing to consider cable effects that would have been relegated to the category of floobie-dust 20 years ago.
SY said:
There is a problem here which is that measures of linearity are not linear. That is, which is more linear, a tube with 20% 2nd harmonic distortion, or one with 1% 17th harmonic distortion? A strong argument can be made for both sides. However, research indicates that the brain will throw out the 2nd harmonics (meaning you actually don't hear them) and actually amplify the 17th. This means that the entire system consisting of amplifier, the speaker, and the brain needs to be considered. Measurements taken at the amplifier output, or even the speaker output, leave out a critical portion of the listening system. Instead, measurements taken at the brain stem, for instance, can show where linearity actually lies. SY suggests that this sort of thing might be an "effects box". However, this is simply a short sighted, and relatively poor, measurement technique optimized for one thing over another with no real basis in reality.
At any rate, to the best of my knowledge, SY has not defined what he means by linear.
As to whether power cords matter, it's about the more ridiculous thing I've ever heard.
Becuase as he shows they are easy to overcome. (you dont need $6K wire). Sure if you use 30 meters of 24 gauge wire to power your speakers, or badly designed amps, or rusty conectors, the wire will effect the sound, but thats a no brainer.
dsavitsk said:
Interesting paper, not the least for proposing a relationship between certain forms of auditory acuity and training. Something to read at lunch, thx!
Absolutely stunning!
I happen to know SY, and his methods to some degree. So far he has been consistent. I am wondering why people are taking pot shots at him.
Now, as for tubes. They are simply devices that react with the circuit they are in. That circuit in combination with the active device (tube in this case) will have a transfer function. The amount of distortion will be dependent on both how well that circuit was designed to a particular tube (I sure hope it's designed to use a "bogey" tube of that type number!!), and how well that particular tube matches the design center for the type. How "good" a tube type is depends entirely how well one sample matches another, and freedom from defects such as microphonics, etc.
Now, what is important about what I just posted there? Every effect s measurable for one. So I'll point out the important bits
1. The equipment is designed correctly for lowest distortion and reasonable tube life. (definition of "properly", or expected traits)
2. The circuit has been designed for the published tube type specifications, the target being a "bogey", or average tube of that type number.
3. The tube used in a test does conform reasonably closely with the expected "bogey" type of that number. (otherwise it's a different tube type)
4. The tube is as free as can be expected from the effects of vibration on it's elements. (it's not microphonic - within reason)
5. There are no other defects in the cathode coating, vacuum or gases that may cause other noise to be present. (like hissing or crackling).
Every single thing I've mentioned is a measurable quantity and may be checked by anyone with the equipment and knowledge to do so. That would constitute my definition of the best tube to use.
Branding of tubes do not reflect the factory they were built in. Often you can find a Mullard actually made by Philips. They are traded as factory capacities and demand varies.
Does that sate your desire for information mach1? Your entire hangup with SY's tube preference is entirely O.T. anyway.
Many other differences can be measured as well. Those measured differences may be small, or tied to another effect. I have measured differences in amplifiers for changes in capacitor type (not brand name), just as I have measured problems due to a capacitor's size. Big caps can both radiate or pick up signals from other parts of a circuit. So, let's drop the capacitor hunt and focus on "power cords" for a change.
I have not, to date, ever heard or been able to measure any difference between power cords on different equipment. That is assuming you are using one heavy enough for the job. The same goes for those silly and dangerous cords made up and hard wired by various charlatans. I have measured differences on power supply performance due to the use of some power conditioners. They simply provided better regulation because the design of the product was poor. On well designed equipment, there was no differences measured or heard.
-Chris
I happen to know SY, and his methods to some degree. So far he has been consistent. I am wondering why people are taking pot shots at him.
Now, as for tubes. They are simply devices that react with the circuit they are in. That circuit in combination with the active device (tube in this case) will have a transfer function. The amount of distortion will be dependent on both how well that circuit was designed to a particular tube (I sure hope it's designed to use a "bogey" tube of that type number!!), and how well that particular tube matches the design center for the type. How "good" a tube type is depends entirely how well one sample matches another, and freedom from defects such as microphonics, etc.
Now, what is important about what I just posted there? Every effect s measurable for one. So I'll point out the important bits
1. The equipment is designed correctly for lowest distortion and reasonable tube life. (definition of "properly", or expected traits)
2. The circuit has been designed for the published tube type specifications, the target being a "bogey", or average tube of that type number.
3. The tube used in a test does conform reasonably closely with the expected "bogey" type of that number. (otherwise it's a different tube type)
4. The tube is as free as can be expected from the effects of vibration on it's elements. (it's not microphonic - within reason)
5. There are no other defects in the cathode coating, vacuum or gases that may cause other noise to be present. (like hissing or crackling).
Every single thing I've mentioned is a measurable quantity and may be checked by anyone with the equipment and knowledge to do so. That would constitute my definition of the best tube to use.
Branding of tubes do not reflect the factory they were built in. Often you can find a Mullard actually made by Philips. They are traded as factory capacities and demand varies.
Does that sate your desire for information mach1? Your entire hangup with SY's tube preference is entirely O.T. anyway.
Many other differences can be measured as well. Those measured differences may be small, or tied to another effect. I have measured differences in amplifiers for changes in capacitor type (not brand name), just as I have measured problems due to a capacitor's size. Big caps can both radiate or pick up signals from other parts of a circuit. So, let's drop the capacitor hunt and focus on "power cords" for a change.
I have not, to date, ever heard or been able to measure any difference between power cords on different equipment. That is assuming you are using one heavy enough for the job. The same goes for those silly and dangerous cords made up and hard wired by various charlatans. I have measured differences on power supply performance due to the use of some power conditioners. They simply provided better regulation because the design of the product was poor. On well designed equipment, there was no differences measured or heard.
-Chris
My college education was in mechanical engineering and mathematics, so none of the science in this debate escapes me nor do I disbelieve it. The argument in question is whether there is an audible difference in cables (and now 12AT7s) and can cable design affect a positive improvement in perceived sound quality despite no measurable difference of conventional properties. Published results from properly conducted double blind testing would go a long way in helping this debate along but so far there is little to be had. I will say this one more time:There is no proof available favoring either side of this debate. Anectdotal evidence is not proof nor are scientific hypotheses, and neither is logical argument. As for Professor Leserf's notes on audio, they are mostly casual and rudimentary (good for you) and contribute little to the literature.
John
tubelab.com said:
If I can hear the difference, it must. The Rogers branded Mullards that were in my amp had audible distortion. I replaced them with Westinghouse tubes and viola, no more audible distortion, even thou they share very similar construction. A distortion spectrum test of different 12AU7's and variants would be very interesting.
Jeff
You do hear them, they change the timbre of the sound. (Anyone who has designed synthisizer sounds will know this) Most instruments have various combinations of even and odd harmonics and these combinations change with factors like direction and loudness. I just finished making 1khz sound files with small amounts (-40db) of 2nd to 7th harmonics individualy added and 1 file of all odd and 1 of all even . I would like to share if someone can tell me how to post short audio files. (there 5 sec 16bit 48k wave files abouy 500k large). Hear for yourselves.
rdf said:
By the way, here is a list of selected publications from the same lab. Lots of good stuff: http://www.soc.northwestern.edu/brainvolts/publications.php
cbdb said:
Email it on my address, and I will post a link.
One more exercise: to make the 2'nd order distortion instead of just a 2'nd order harmonic, so the louder is the signal the more it is distorted.
I spent many hours of experimenting when designed analog synthesizers and effect pedals. And indeed, the higher is the loudness of acoustical instruments, the richer they are on harmonics.
One classical instrument that produces almost odd harmonics of wide specter is clarinet. Flute produces almost sine wave. In order to synthesize piano each string needs to have different contents of harmonics. Strings produce much more complex signals than just a fundamental and harmonics, but using simple synthesis that involves as well phase modulations of 3 synthesized waveforms changing when decay perception may be fooled well enough.
cbdb said:
You are correct, I was slightly exaggerating. It seems to be that consonant sounds cause the creation of additional consonant sounds structures in the brain, and dissonant ones cause the creation if more dissonant ones. The brain does a lot of manipulation, even at the brain stem level, and this is just beginning to be understood. Indeed, the way the brain responds to sound is a function of how ones brain has been trained.
cbdb said:
Here are some popular sites that people use for posting needledrops:
mediafire
zshare
download.yousendit
sendspace
Jeff
The brain is also able to form the (what would normally be subsonic) fundamental of tone if given the (audible) second and third harmonic.
John
John
cbdb said:
Good luck!
You may post me a raw bass guitar record so I can show you how it sounds through my Waybeyond bass guitar rig.
Hi John,
Actually, the effect you are referring to pertains to normally audible frequencies that are missing when played through a "frequency constrained" system (read: crap). Those overtones that shouldn't exist are the result of a speaker "frequency doubling" and are normally distorted.
However, you are quite correct in saying that the brain is more than capable of filling in missing information. In fact, we can hear entire sounds that did not occur simply because we expected them to. Pretty neat trick.
Consider one fact though. When looking for evidence in a crime investigation, the least reliable information is an eye witness account according to police investigators. This fact gets proved again and again every day.
I'm not saying that human observation is worthless, because it isn't. I'm only saying that we have to be extremely careful about what we accept as fact without some other kind of evidence to back things up.
-Chris 😉
Or an Audio Control sub harmonic box to create the (never existed) tone.
Actually, the effect you are referring to pertains to normally audible frequencies that are missing when played through a "frequency constrained" system (read: crap). Those overtones that shouldn't exist are the result of a speaker "frequency doubling" and are normally distorted.
However, you are quite correct in saying that the brain is more than capable of filling in missing information. In fact, we can hear entire sounds that did not occur simply because we expected them to. Pretty neat trick.
Consider one fact though. When looking for evidence in a crime investigation, the least reliable information is an eye witness account according to police investigators. This fact gets proved again and again every day.
I'm not saying that human observation is worthless, because it isn't. I'm only saying that we have to be extremely careful about what we accept as fact without some other kind of evidence to back things up.
-Chris 😉
jlsem said:
Oh?
Perhaps one should then firstly define truth - because the truth about truth sometimes appears to be a quite untrue playing field - amazing though that seems.
The quote follows I think after SY's summary of his tests (which, by the way, agrees with what others of us have found). You neatly mention 'scientific hypotheses' and 'logical argument'; why not scientific facts?. This is where I stop short and am asking for your particular definition of thruth. Not to humour you ... but if 'logical argument' does not eventually arrive at the same destination than 'truth', I have an empirical difficulty (provided of course that logical argument does not get derailed by untruths - def: matters at loggerheads with established facts).
To continue: When one uses properly calibrated equipment to measure performance of a tube/whatever (as we are assuming here), how in [unpleasant word] can that not be accepted as proof?? Therefore your words above mystifies my. SY has explained in his relevant first post how he went about reaching his findings, yet he is challenged more than once on those?!
In general:
I also find it humorous that subjectivists insist on 'I have heard it, therefore it must be so (Oh? - one or several 'observations' by a single person, and he is challenging dogma??) - yet recognised scientific measurements are questioned on far greater wispy threads of uninformed doubt than invades 'anecdotal evidence', as Jlsem has correctly stated above.
There are mainly two reasons why this sort of argument will never be 'solved', as stated by some:
1. Because it has already been solved,
2. ...with further discussion now mostly for the benefit of the either genuinely not-knowing doubters (with some hope of success), or those too stubborn/arrogant/self-centered to accept anything not in agreement with their entrenched convictions.
We did an interesting experiment in an anatomy/physiology class. There was some sort of special design that our teacher handed out that contained a dot somewhere on it. The experiment involved staring at a certain area of the design and varying the distance from the paper to the eye. At some point, the dot would disappear. It never occurred to me before that I had a blind spot in each eye before then.
You are mad if you think that your senses are the best way to get the truth. You have to use your brain, too. (not you Chris, I mean the all-inclusive 'you')
http://en.wikipedia.org/wiki/Blind_spot_(vision)
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