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How do the 'non-subjectivists' choose their hi-fi systems?

Discussion in 'audio' started by Pete L, Apr 25, 2020.

  1. tuga

    tuga Legal Alien

    It's all a bit over my head to be honest.
    That paper is not free to download. I have this older Otala paper in my library:

    Transient Distortion in Transistorized Audio Power Amplifier
    Matti Otala
    lEEE TRANSACTIONS ON AUDIO AND ELECTROACOUSTICS VOL. AU-18, NO. 3 SEPTEMBER 1970

    Abstract
    This paper discusses a new kind of distortion mechanism found in transistorized audio power amplifiers. It is shown that this distortion arises from the multistage feedback loop found in most high-quality amplifiers, provided that the open-loop transient response of the power amplifier is slower than the transient response of the preamplifier. The results of the analysis are verified by measurements from a simulated power amplifier, and a number of constructional rules for eliminating this distortion are derived.
     
  2. mansr

    mansr Objectionist

    tuga likes this.
  3. h.g.

    h.g. pfm Member

    Engineers do not normally have a free hand to design low tech consumer electronics in the way implied by the marketing. The spec of a new model is likely to have most input from the sales and production teams with the engineering team largely delivering the vision of others. If you look at the CV of many of the names that get hung on home audio hardware to help with the marketing you will see they usually don't have a formal engineering background and have often come from the sales side. There's nothing wrong with this and if you talk to (real) engineers they usually have a lot of respect for their sales and production teams. This isn't a hard and fast rule though and there have certainly been one or two "proper" engineers recently that have picked up the job of becoming a celebrity to help the marketing. We live in strange times when "proper" engineers are prepared to do this!

    I have no doubt that examples can be found of amplifiers that sacrifice too much performance elsewhere to get very low THD into 8 ohm at 1 kHz figure to support sales. This doesn't mean that competent trained engineers were unaware of what was being exchanged. I haven't looked closely but the SID/TIM/TID/... stuff looks suspiciously like a marketing push to sell amplifiers on a different figure of merit. It was a bit late though because growing numbers of consumers were shifting to audiophile subjectivism and giving technical specs little weight when it came to choosing which amplifier to purchase. De-emphasising the THD at 1kHz into 8 ohms figure in the marketing was likely beneficial for the consumer though.
     
  4. DimitryZ

    DimitryZ pfm Member

    You are very skillful at avoiding a direct answer, a quality that is surely important in academia.

    However, I am pretty sure that you know that most if not all DBT protocols are severely flawed, for reasons I stated multiple times.
     
  5. tuga

    tuga Legal Alien

  6. awkwardbydesign

    awkwardbydesign Officially Awesome

    Oh Lord! I have only got to page 14 so far, and I don't understand most of that! But I have had two John Curl designed Parasound amps, and liked both of them.
     
  7. tuga

    tuga Legal Alien

    His design skills are better than his writing ones then.
     
  8. awkwardbydesign

    awkwardbydesign Officially Awesome

    No, my comprehension level is the problem. I left school at 16!
     
  9. tuga

    tuga Legal Alien

    Clarity is not his forte, though.
     
  10. tuga

    tuga Legal Alien

    At the end of his article "Some Factors In Loudspeaker Quality" (Wireless World, May 1976) BBC's H.D. Harwood (Harbeth's dad) issues the following warning:

    A/B testing

    Now the alarming fact is that A/B testing may under certain circumstances give rise to completely wrong results when comparing the sound quality of two loudspeakers.
    If pink noise is used as a convenient source, and a deep narrow crevasse produced in it, it has been shown that the effect will be almost inaudible.
    If this is listened to for, say, half a minute as if programme were being used to judge a loudspeaker, and then the crevasse is switched out so that a uniform spectrum is produced, the ear will hear a strong colouration at the frequency of the crevasse.
    It seems that there are two mechanisms at work; the conscious one ignores the crevasse but the subconscious one detects it clearly.
    When the uniform condition is suddenly heard the subconscious mechanism comes forward and points out that there is now a considerable amount more sound energy at the frequency of the crevasse, and as that condition had been accepted as satis-factory the only conclusion to be reached is that there is now an excess in this region and that the sound must now be highly coloured.
    Transferring this to loudspeakers it is implied that if one with a crevasse is first listened to then it will probably appear that one with a uniform response is coloured.

    https://www.americanradiohistory.com/UK/Wireless-World/70s/Wireless-World-1976-05.pdf
     
  11. awkwardbydesign

    awkwardbydesign Officially Awesome

    But a difference has been detected, which is the point of the test, no? A preference is another thing entirely.
     
    mansr likes this.
  12. awkwardbydesign

    awkwardbydesign Officially Awesome

    Why am I defending A/B testing? :rolleyes:
     
  13. h.g.

    h.g. pfm Member

    I find it hard to believe anything from an out-and-out audiophile like John Curl is going to be informative and I am sorry but I am not going to waste my time looking in this case. When I first came across him on a forum and knowing he was a "designer" of amplifiers I tried to get him to translate some of his "rantings" on amplifier design into conventional engineering design decisions and that was revealing.

    Having said that my speculation on the SID/TID/TIM/... stuff as marketing is speculation from someone who at the time was sufficiently disgusted with the arrival of the audiophile phenomenon (which in my intolerant youth I saw as straightforward dishonesty with everyone involved on the supply side knowingly pushing snake oil) that I jacked in a career in home audio and shifted to another form of engineering. The form of distortion is of course perfectly real it is the promotion of it at the time that is suspect plus any claims to it not been known.
     
  14. mansr

    mansr Objectionist

  15. awkwardbydesign

    awkwardbydesign Officially Awesome

    What did it reveal, though?
     
  16. awkwardbydesign

    awkwardbydesign Officially Awesome

    Darren likes this.
  17. DimitryZ

    DimitryZ pfm Member

    Same with tasting. Exposure to same flavor acclimates the palate, sudden absence appears as wrong.

    Thats the purpose of pickled ginger on a sushi plate - to refresh and "erase" the flavor memory so that subtle differenced can be enjoyed.

    To others, though, fish is fish - tastes the same.

    I bet we can show that a standard eater can not distinguish yellow fin tuna from regular tuna under strict double blund test condition. Voila - an entire cousine/art form can be declared as fake and unnecessary.
     
  18. Darren

    Darren All Business

    That is such a great blog. She seems lovely. This caught my eye:
    "It seems to be audiophiles are not only predominantly men, but middle-aged or older men, most of whom seem more opinionated than most, grumpier and more argumentative than most, and more inclined to show off."
    Obviously that doesn't apply to any of us here on PFM...... does it?
     
    Fretbuzz likes this.
  19. h.g.

    h.g. pfm Member

    It revealed his knowledge base and to some extent his character as a person. Nonetheless hats off to him for engaging interactively and exposing himself to judgements for the audiophile nonsense he peddles particularly as he is pretty thin skinned.
     
  20. awkwardbydesign

    awkwardbydesign Officially Awesome

    I took something different from your post. The clue was in the part I highlighted.
     

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