protos said:
On the production floor where I work, we use ultrasonic welders to melt plastics together..the units operate at 25Khz, in the 500 to 2 Kw range.
When they are operated, I can detect it..I can't hear the signal itself, but somehow sense it..
I think (but I'm not sure) that the hearing mechanism responsible for the agc function of the human hearing response is fooled into turning down by the intensity of the u/s..so I think that all the other background noise seems to reduce in volume..even though the u/s signal is inaudible, it seems to affect hearing the other stuff..
Cheers, John
I have always been shocked that the difference in sound between power cords is more apparent (even to inexperienced listeners) than the differences between speaker/interconnect wire. Yes, it goes against any intuition and conditioning and yes, i don't really like it but it is clearly audible on practically any kind of equipment - cd, amps, synchronous turntables (with no regeneration).
It will be really surprising if one's ears have sufficient resolution to distinguish between speaker cables but not between power cables.
It will be really surprising if one's ears have sufficient resolution to distinguish between speaker cables but not between power cables.
protos said:
It's a classical argument because it's been shown beyond doubt that humans may perceive differences even when none exist (and I don't mean differences that can't be measured, I mean there were simply no changes made). And that until that possibility is ruled out, there will always be ambiguity as to exactly why someone perceived some difference.
What I've never been able to quite understand is why this possibility is so rarely even considered even as a possibility. Whenever some number of people purport to perceive differences with regard to a certain issue, it's almost always automatically assumed to be due to some physical cause.
It's one thing to not care what the actual cause may be and just go with whatever works, which is pretty much what I do. But if one is truly interested in what the actual cause may be, being in denial of very real possibilities isn't going to get you that answer.
se
Here's a recent article that ought to relevant:
http://www.nytimes.com/2003/10/26/magazine/26BRAINS.html
A neuroscientist compared regions of brain activity in blind and non-blind taste tests. In blind taste tests, the activity was mainly in regions responsible for sensory input. In the non-blind tests, it was in regions responsible for higher level cognition.
Anbody got any spare MRI time?
http://www.nytimes.com/2003/10/26/magazine/26BRAINS.html
A neuroscientist compared regions of brain activity in blind and non-blind taste tests. In blind taste tests, the activity was mainly in regions responsible for sensory input. In the non-blind tests, it was in regions responsible for higher level cognition.
Anbody got any spare MRI time?
It's DEJA VU all over again
You have got to be sh***ing me! I thought trolling was prohibited @ here.
A pointless thread with almost literarlly the same title appeared in this forum about 2.5 years ago back when there barely was Fred. Even with all different people the discussion lead nowhere, except maybe the sin bin for someone.
I am surprised that no one noticed.
You have got to be sh***ing me! I thought trolling was prohibited @ here.
A pointless thread with almost literarlly the same title appeared in this forum about 2.5 years ago back when there barely was Fred. Even with all different people the discussion lead nowhere, except maybe the sin bin for someone.
I am surprised that no one noticed.
grataku said:
I'm sorry...I'm relatively new here..
The fact that I have to assert that powercords can make a difference indicates to me that the issues which are relevant to powercord based "distortions"have not been discussed here..
PSRR and noise rejection are not what I refer to..nor crystal grains, nor skinning, nor inductance, nor dielectric material, nor dielectric color, nor stranding, nor silver, nor copper.
Cheers, John
PS..on occasion, somebody outside the interest group may bring a new understanding to a topic..I consider myself as (up to recently), an outsider to this group...and I do not "troll"..nor, do I have any intention of injecting "pointless" information.
Christer said:
No. And, I took no offense, even if I were the target..
What I take exception to is the statement "A pointless thread ".
Since I have stated that the premise is supported by e/m theory, and is testable with equipment, it is obvious that he did not read fully the posts..just reacted with a knee jerk. If he had read fully, he would have called me to task on how it is possible that I believe it can be measured....Since he did not..he obviously did not read..
And, I agree...strong accusations should be prefaced with direction..
Cheers, John
Power Cord break in
I've got a story for all of you. A critic let me borrow one of these power cords that had this cylinder on it to slide it up and down the power cord to "tune it" for best sound. Well I did a little experimentation and found that if I connected it to my pre amp and put this cylinder in the middle of the line cord, I would get grossly distorted bass. Hmmmmmm.
I brought the thing into work and put it on the HP LCR meter and did not find anything unusual until I started to measure the phase of the current when the cylinder was in different places. I observed that when the cylinder was at either end of the line cord that the phase of the current was at -7 deg. When the cylinder was placed in the middle of line cord the phase of the current went up to -25 deg.
I consulted with some of the other engineers I was working with at the time and we all agreed that this was the result of magnetic field.
Vans Evers, the "designer" of the line cord did not want to discuss this issue. The critic who let me borrow it wanted to believe it was something else, and I was thoroughly ****ed off that idiots would promote magnetic field when most responsible designers are trying to limit this because of such things as distortion.
In any case; if you want your power cord to break in, follow my grandmothers advice and soak it in kosher chicken fat overnite.
I've got a story for all of you. A critic let me borrow one of these power cords that had this cylinder on it to slide it up and down the power cord to "tune it" for best sound. Well I did a little experimentation and found that if I connected it to my pre amp and put this cylinder in the middle of the line cord, I would get grossly distorted bass. Hmmmmmm.
I brought the thing into work and put it on the HP LCR meter and did not find anything unusual until I started to measure the phase of the current when the cylinder was in different places. I observed that when the cylinder was at either end of the line cord that the phase of the current was at -7 deg. When the cylinder was placed in the middle of line cord the phase of the current went up to -25 deg.
I consulted with some of the other engineers I was working with at the time and we all agreed that this was the result of magnetic field.
Vans Evers, the "designer" of the line cord did not want to discuss this issue. The critic who let me borrow it wanted to believe it was something else, and I was thoroughly ****ed off that idiots would promote magnetic field when most responsible designers are trying to limit this because of such things as distortion.
In any case; if you want your power cord to break in, follow my grandmothers advice and soak it in kosher chicken fat overnite.
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