lumanauw said:
I agree with this and have said so many times. It's a very good premis to develop an alternative way of looking at amplification.
I mean this in a nice way.PMA said:
Judging from the many excellent performance charts you've posted you place ultra low distortion very high on the list of must haves. This does not automatically make it number one on the paretto of necessary items for accurate reproduction of recorded music; just one of the ingredients.
Just a different point of view...
I tend to agree, PMA, but 3 tones will actually give some advantage due to 'triple beat distortion'. It just gets too confusing with too many test tones. The distortion sort of grows like 'grass' between the test tones. Still, Nelson's paper is a good read, but it will be picked apart by the hear no difference people, because it is not a masters thesis. It is frustrating that we get picked and poked over relatively trivial issues in papers that engineers generate to bring out their point-of-view. Walt Jung got a paper rejected 30 years ago, for the JAES, because some professor didn't like the math. He didn't know why he didn't like the math, but being a peer reviewer for the AES, apparently didn't mean that he had to prove his criticisms. Happens the same with my efforts, as well. Tends to scare off conformists, even if they are pretty good engineers, as it might make them look bad to an employer, Dolby for instance. This actually happened in regards to Walt's rejected paper.
john curl said:
It is also frustrating to watch audio industry leaders preaching ultra low distortions, while their own commercial products are anything but (however, they "sound good").
I would also count as frustrating the confusing slide without border along engineering, GEB and voodoo.
PMA said:
Which pretty much shows you don't have the foggiest idea on how the peer review process is running, at least for important scientific journals.
It's not a "professor" that accepts or rejects a paper, but the paper is sent to 3-5 individuals that are usually selected based on their previous (on topic) contributions for the journal. The reviewers have first to choose if the paper is on the journal topic. Then the content evaluation form that each individual has to fill in has usually 4 grades "Publish immediately", "Publish after a minor revisions", "Publish after a major revision", "Reject". Only if the peers do not agree on a verdict (e.g. one says "Publish immediately" and another one says "Reject" the paper goes to a member of the scientific board, a "professor" but this happens once every decade, I guess. The evaluation reports with the grade (which also contain a detailed description of the objections) are then sent back to the author(s) and it is up to them to revise the paper according to the objections (or debate them) and resubmit. It is important to mention that the reviewers are completely anonymous for the author(s) all along the process.
So the claims that a certain "professor" rejected a particular paper submitted to a scientific journal are just :bs:, unless the journal is a piece of junk by itself, not worth of any scientific classification. Of course errors happen in the process, even famous scientists had rejected papers, there are ideas that were way ahead their time, etc... it's a fact of life. But, in general, the system is as good as democracy. Not perfect, but the best of all worlds. Because of this, a brilliant mind won't be turned off by a first rejection; it would rather understand the objections and review his work in an attempt to improve the communication, add details, further explain and justify his conclusions, etc...
If you can imagine a better process, you are free to contact the journals and speak up.
Sorry for the OT, let's go back to voodoo
dimitri said:
YOU HAVE GOT TO BE KIDDING ME????
ONE???
I didn't realize it was that bad. I've had my doubts and uncomfortable feelings regarding the AES, but that's just ridiculous.
One..pfffft.
Imagine me submitting a skin effect article which has information, test setup details, and test results which were contrary to that published by MH in '85.....guess who it would go to for review??
Cheers, John
scott wurcer said:
WHAT? I never published there, but if this is true, then the whole AES thing is a joke. Anyway, the AES web site http://www.aes.org/journal/infoauth.cfm says a different story:
Regarding conferences, there are lots of otherwise very strict journals (one that I recall is Journal of Electrochemical Society) that have a very lax policy for the bi-annual conferences. Almost everything can be sent and published in the Proceedings.
dimitri said:
Well, then the whole JAES is junk, which is a completely different topic. I'm wondering why people are still submitting their work there. There are other journals, (e.g. IEEE Transactions on Audio, Speech & Language Processing http://www.ewh.ieee.org/soc/sps/tap/edics.html) that are waiting for contributions.
Hi, PMA,
If I get 4 tones of 1khz, 2khz, 4khz, 8khz with equal amplitude, how high 16khz IMD residual will be?
Good point. Xover distortion does not happen only at 1 frequency. If an amp has it, it will happen at 150hz, 1khz, at 2khz, at 3khz, at 10khz, at 11khz, at 12khz, at all tones, worse with higher frequency. Is it possible that the IMD sum of all those that we can actually hear, but not from a single tone? I try to hear disortion with 1 tone, very difficult. I can recognize when it clips, but beyond that I cannot hear much difference.
If I get 4 tones of 1khz, 2khz, 4khz, 8khz with equal amplitude, how high 16khz IMD residual will be?
I agree. To those skilled and experienced, I think he can "predict" by looking at FFT residual of 1 tone.
Harmonics will generate harmonics, but no non-harmonically related products. You really need non harmonically related tones, and the spectral contamination tests require a lot of numbers with no IM or harmonic relationships. to create the windows to look for stuff that should no be there in the output. Crossover distortion will create these "bad" products fast but not with a pure sine wave.
This is a list of tones that meet the requirements of non harmonic etc.: 100.00 122.00 261.80 348.20 685.40 987.00 1794.40 2871.10 4697.90 6764.90 12299.20 16357.90
This is a list of tones that meet the requirements of non harmonic etc.: 100.00 122.00 261.80 348.20 685.40 987.00 1794.40 2871.10 4697.90 6764.90 12299.20 16357.90
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