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  1. j_j

    High Resolution Audio: Does It Matter?

    In the modern day, it's trivial. And for the test Bob described, you'd be better off with yet another filter, that one starting to cut off at 25kHz and finishing at 32kHz. Shorter, no possible interference in the time domain based on current understandings of cochlear dynamics. Filter created...
  2. j_j

    Does Phase Distortion/Shift Matter in Audio? (no*)

    I use allpass sequences to get better SNR and a more accurate impulse response, but I set up DUT on the edge of my deck which is 12' up. I put the mike 2' in front of it. 20 seconds of "flying saucer" noises and I have a first reflection at about 19 to 21 milliseconds, depending on how high...
  3. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    I believe you're mildly mistaken on the "back of the room" comment. They most certainly affect sensation, but I don't think "back of the room is the same" was my point, rather that delayed reflections like that can mess up articulation. I'm not in agreement with the "early reflections" crowd...
  4. j_j

    Does Phase Distortion/Shift Matter in Audio? (no*)

    Indeed, "no way to interpret the results" because the result of '0' makes the transform singular (information is lost) unless you stick to complex domain. Which is a whole other ball of wax. The issue at pi creates another issue, in that this creates patterning in half-band filters used for...
  5. j_j

    Does Phase Distortion/Shift Matter in Audio? (no*)

    First, "sliding the signal back and forth" adds a phase shift to every frequency of phi = 2 * pi * f * t, where phi is the phase shift in radians, f is the frequency in Hz, and t is the time in seconds. This shows that you only get a phase shift of "pi" at ONE FREQUENCY, so sliding the waveform...
  6. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    And, very importantly,how the miked material, however it was captured, is actually inserted into the final master. I have much to say and demonstrate on that point, but I am presently unable to do so.
  7. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    I wonder if I have any photos of "Harvey the Head" from BTL, it used to sit on a shelf in my lab. I'm pretty sure Lucent has disappeared it.
  8. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    I have to say there's a few more using good methods that are not generally (yet) available, but one ***MUST*** stay away from the "encoded versions". There is a host of disasters lurking there. It would be (yes, we have one) a codec that can do a lot better job, of course with more bits, but...
  9. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    ATMOS is primarily a loudspeaker format, I'm disturbingly well aware of it, and of how it creates some very unhappy results when used in the "most heavily coded" variety. Atmos (the actual physical format) can be created in any one of a large number of ways. It's HOW it's created, and how well...
  10. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    I think the question is purely semantic. I'm too old for scotch except in tiny quantities, but a good CMS would do. But, frankly, my argument is that whatever gestalt you want to create must have the necessary cues present to create it. Preference can be involved, or not, but there must be...
  11. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    Oh, my opinion on Quad failing was very simple, it didn't provide enough gain in actual experience to be worth it, on top of various recording and playback issues. The "one seat only" was also a problem that limited the market. The "one seat only" was due to bad production methods, but I'm not...
  12. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    A modern understanding is that the interference between two signals, l and r, with coherent signal, interact with the HRTF's of the listener to produce a midrange dip as well as some time domain confusion, which masks the time domain distance cues for moderate (not near field or far field)...
  13. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    A lot of unnecessary argumentation and seemingly sham nonsense removed. Having someone apparently familiar with USENET has to know that it evolved from "netnews" and based on MOST of the content in all audio groups, "nutnews" is most certainly a reasonable description, and certainly not a rare...
  14. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    That's not what I asked for, I asked for the nutnews citation, as you well know. You've asserted that I am completely opposed to Heyser's work, which is flat-out false, although since he did not have a couple of decades of learning about the auditory system in hand, I rather think I have reason...
  15. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    Well, I would like to see exactly what parts of that I disagreed with. For some parts of the system, there is "absolute sound", in the electronic sense, in particular. However, even way back then, I will point out perceptual coding was a real thing (dating back to 1983/84) and the need was...
  16. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    No, the white board and the camera on me went into a switcher. It was not a background replacement. Trust me on this, I was, after all, there. There were a couple of cameras, a direct feed from my laptop, and a camera that sometimes got me and the screen for the local people in it, and...
  17. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    Well, to your first question, some IM signals at higher frequencies can lead to products right at the ear canal resonance, which makes them annoyingly audible. While this is not always a problem, it's a very real problem for some kinds of percussion and bells. To the ladder? I really don't...
  18. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    Plot the ERROR SPECTRUM and compare it, using the response of the rest of your system past that device, to the actual absolute threshold. There are a lot of amplifiers that still choke on tricky loads. There are a lot of devices that have bad noise rejection. A pure ThD rating at 1kHz and...
  19. j_j

    Announcement. AES Presentation on “What is Accuracy” by our very own member @j_j_ or James D. (jj) Johnston - Chief Scientist - Immersion Networks

    Recording is available now there. Report will appear in a week, take or give, at www.aes.org/sections/pnw
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