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Old 30th December 2011, 10:20 PM   #401
Pano is offline Pano  United States
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Quote:
Originally Posted by Steve Eddy View Post
But of course didn't land there until '69.
I figured someone might mention that. FWIW, The Soviets landed on the moon ten years earlier, in 1959 (unmanned). I don't own any late 50's Russian recordings, wonder how they sound?
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Old 30th December 2011, 10:22 PM   #402
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Does feedback 'cancel' delay or does it OVERCOME delay? Think it through, DF96.
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Old 30th December 2011, 10:26 PM   #403
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The Soviets really were first in many instances. They just could not keep it up, perhaps because we could throw much more money at the challenge. However, this extra money is why I learned so much, so early in my design experience.
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Old 30th December 2011, 10:29 PM   #404
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Feedback acts, in effect, as a complementary filter as it supplies (at the input) approximately the signal you need to get the required output. Anyone who understands control theory will tell you that controlling a loop with a single-pole LP filter or an integrator is easy, but a loop with a genuine time delay is much harder.

I'm not sure whether you would want to call this cancellation or overcoming but the effect is the same. You can't cancel/overcome a genuine time delay without using a time machine. I don't think any audio website is yet offering a room temperature time machine.
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Old 30th December 2011, 10:33 PM   #405
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Think it through again, as what happens at the input stage, in order to compensate for the low open loop bandwidth. What happens? What changes in feedback voltage appear?
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Old 30th December 2011, 10:36 PM   #406
tvrgeek is offline tvrgeek  United States
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As long as they don't forget to convert kilometers into miles

So, we have audio amps with incredible bandwidth, stable on loads that are stupid, DF that is no more than a couple inches of wire, THD, IM, TIM, SID, "LBJ took the IRT down to 4th street USA...." * and yet, there is something that may be known, but I can't point to, that causes some amps to accentuate/create something in reproduction of a trumpet that does not occur live that makes my wife's teeth grate. Considering all the terrible things that happen to a signal from mic to speaker, it baffles me that this last stage has something audible. I guess we just don't know.

I am going to propose to the local dealer that when they have a small Halo out of the box, I being my amps, speakers, "bad" music and my good wife to see if whatever it is has been beaten into submission. It is a relevant datapoint to say it is solved even if we don't know which of thousands of issues solved it. That would be the outcome I expect. Of course, we learn more when the outcome is not what we expect.

Still, I will play with my old junk and see if I can change it. My parts are still not here. ARRRRG. Anyway, I cut out the MDF for a set of speakers for my Nephew. Crossover is modeled as a starting point and a plan for what finishing technique I will try on this set. When all else fails, there's nothing like making sawdust. I will then troll Amazon for a used book or two as referenced. Books may not have the answers, but the good ones have the questions.

* To the young whipersnappers out there and the international readers, my reference is to the 60's musical "Hair" a song titled "Initials."
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Old 30th December 2011, 10:51 PM   #407
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Hey tvrgeek,

I keep thinking about all the combinations of stuff that we use. This speaker1 sounds great with that amp1 but with amp2 it sucks while amp2 sounds great with speaker2... if the amp is not designed to drive something specific, it really is a craps shoot.

Can there really be one amp to rule them all? i doubt it.

good luck,
revb.
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Old 30th December 2011, 10:59 PM   #408
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Quote:
Originally Posted by john curl View Post
The Soviets really were first in many instances. They just could not keep it up, perhaps because we could throw much more money at the challenge. However, this extra money is why I learned so much, so early in my design experience.
Soviets had what they called "Scientifically Planned Economy", or what we call now, "Global Economy", when it is possible to throw resources where they are needed for a break-through. American capitalism then was more effective, since people really owned businesses, calculated own money adjusting all decisions to the reality. If money is "theirs" (Central Bank in Soviet Union, or Reserve Bank in Global Economy), things are quite different...

Edit: Tvrgeek, add to your challenge one more thing: Denon AVR-591. It is very cheap amp, but sounds better than many boutique designs. I was surprised when heard it first: i bought it as a donor for it's Audissey DSP, but use almost an year as-is.
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Last edited by Wavebourn; 30th December 2011 at 11:04 PM.
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Old 30th December 2011, 11:29 PM   #409
SY is offline SY  United States
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Quote:
Originally Posted by Wavebourn View Post
Excellent by "standard measurements", or excellent by clearness of sound?
I didn't know they were mutually exclusive.
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Old 30th December 2011, 11:31 PM   #410
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There are not mutually exclusive. That they don't seem to be mutually inclusive is the topic of thread.
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