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In Reply to: RE: Slew rate, TIM hogwwash posted by Paul Eizik on July 11, 2017 at 16:02:29
But you still don't acknowledge the engineering problems I raised that clearly contradict Otala's claim that this is audible with program material. Ahh, but did he even say that? I do agree it might be audible with test signals but then that's not real program material we listen to.
Just more "appeal to authority". Typical audiophile response when presented with real engineering problems that dispel their beliefs..
Follow Ups:
I think I see where you're going with this, you are intending to write a JAES paper and you are testing some of the ideas out here. Here's some suggestions to clean up the argument:
To say something is hogwash is to say it's useless and should be thrown away, so drop the hogwash and just say that. You would be expected to provide at least some rudimentary test results, so just have some buddies over for beers and test them. If you add some TIM to a musical selection you are adding energy to the signal and thus effectively raising gain, and that's an old Hi fi salesman trick to turn the volume up a bit to make the thing you are trying to sell sound better. With this you can probably get some people to actually prefer the TIM'd examples, and Otala did note that some of the test subjects did. It's also fairly easy to prove that people are guessing during audio tests if you make them guess, so do rapid switching among orchestral recordings with both loud and quiet passages. After awhile they won't even know what ocean they're in.
You have criticized Dennis and Jeff for promoting speculative and unsubstantiated theories, and you also leave yourself open for criticism in this regard if you don't provide something a bit more concrete. Lisa Randall once said to me when I asked her a question about Loop Quantum Gravity that "It's just a theory", though she did admit she respected the author of LQG. So far you just have an interesting theory, but the ear is the final arbiter in all things audio to paraphrase Olson. And it wouldn't hurt for you to make some appeals to authority too.
BTW Otals did say that the 0.003% TIM was clearly audible to the six golden ears on musical selections, but he noted that they could only hear a difference, but not identify which version had the TIM added. That alone would seem to open an area to study. Also Otala did use square waves as you stated, but he also used triangle waves in some of the tests too.
We're pull'n for ya!
Paul
"You have criticized Dennis and Jeff for promoting speculative and unsubstantiated theories, and you also leave yourself open for criticism in this regard if you don't provide something a bit more concrete. Lisa Randall once said to me when I asked her a question about Loop Quantum Gravity that "It's just a theory", though she did admit she respected the author of LQG. So far you just have an interesting theory, but the ear is the final arbiter in all things audio to paraphrase Olson. And it wouldn't hurt for you to make some appeals to authority too."Stupid analogy! I have provided evidence based on simple physics why TIM is not an issue with acoustically produced sound. You have yet to comment on the theory I have presented. All we hear is "Otala says, Otala says".
As for listening tests, first of all 6 out of 83 is hardly a convincing sampling. We also don't know the controls present or how these tests were conducted. ABT, DBT? "I'm going to play some TIM for you, tell me if you hear it?" Yes some classic audiophile tests were that unprofessional.
You also fail to separate the technical facts of TIM versus the final effects on the systems as a whole. Sure it can be simulated, but does it present an issue in real world audio reproduction? Basic atmospheric and mechanical physics says it can't.
Ok so you don't like TIM being called hogwash. Perhaps you are right in that TIM is real and can be demonstrated - with test equipment. But what is hogwash is that we can hear TIM with modern audio amplifiers designed with late 70s / early 80s technologies.
I'm tired of hearing your monotonous references to 40 year old research papers - OK, 39 years old in fact. Show me how an acoustically produced square wave rise time within the human hearing range can exceed the path delay of a typical DC coupled audio amplifier. Show me a microphone that can capture such an event even if out atmosphere would allow such a pressure wave to propagate in the fist place?
Again show me the math that supports TIM audibility! I know a test generator can do it. But what about real music, sound effects, and speech?
P.S. "If you add some TIM to a musical selection you are adding energy to the signal and thus effectively raising gain"
This is not totally correct either. You are thinking solely of harmonic distortion. IM distortion does not follow the same rules. Look up Bessel functions.
Edits: 07/12/17
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